Author Archives: mark.hunt

August 6th

Hi All,

As we enter our 10th week of pretty continuous hot and dry weather, we have a change on the way as correctly predicted last Monday with some cooler and unsettled weather on the cards. That’s precisely what awaits me in Alaska with some pretty significant low pressure systems doing the rounds and plenty of bears across the river from the camp feeding on Wild Blueberries apparently. Should be interesting……

It is a change that won’t be welcome news for farmers maintaining crops like this and as I noted the dust clouds rising over The Welland Valley yesterday whilst out walking, I sensed urgency in their work. Like our industry, they have had a very challenging year, cold winter, wet and cold spring, driest, hottest summer, you know the thing. For sure it is already causing an impact as you see cows and sheep being fed hay in the fields because the grass growth is insufficient for grazing. I ground up an ear in my hand from the wheat field on the right and the grains were really small, lots of screenings this year and for sure lower yields of grain and straw, so we will see this in our pockets when bread and milk prices rise.Their industry is already incurring significant extra costs and will likely lose money on poor yields, but what of ours ?

It made me think about the effect of this years weather on our industry over the course of the year, for sure a loss of rounds and revenue early on with the wet spring and winter snow closures. Since then it’s surely been good from that perspective with less issues regarding playability, less cutting, more watering, less disease pressure (less humidity), poor Poa growth, more seedheads, good bent growth, I could go on… It is ‘swings and roundabouts’  on our side of the fence.

All in all though has a long run of dry and hot weather been negative do you think ?

I wonder if we will carry some sort of legacy into the autumn with a grass plant that’s been on the back foot for such a long time and I also wonder in a year of extremes, what the autumn will bring weather-wise ?

Will we sign off 2018 with the warmest, wettest autumn ?, lets hope not and no I haven’t a clue at the moment.

General Weather Situation

So we start the week as we finished it with another hot, dry day for England and Wales on Monday. We have low pressure sitting north-west of the U.K and the above Meteoblue image shows the typical demarcation line when it comes to cloud and rainfall of late with Ireland, Scotland and north-west England ‘enjoying’ thicker cloud cover and cooler temperatures. So a cool and showery day for Scotland with some light rain, mainly across the west, Ireland pretty dry but cool under that thicker cloud front and England and Wales set for another extremely hot day. I expect temperatures again in the high twenties, low thirties today with a gentle wind from the west, increasing in the afternoon as convection sets in. High teens for Ireland and Scotland.

Onto Tuesday and a very similar picture with the thicker cloud base and rain following the same pattern as Monday. Maybe more chance of some rain across the north-west of England and east of Scotland for a time on Tuesday morning, but this fizzles out to leave just thick cloud cover. A dry, cloudy day with perhaps some breaks in the cloud for Ireland during the afternoon but rain will push into the west just before midnight. For England, a re-run of Monday, hot, dry and sticky but already the impact of that cooler air pushing in from the west will be felt across Wales with temperatures down in the low twenties for the day. For England we will see similar temperatures to Monday but there’s a risk of moisture pushing in over The Channel into the south-east and east of England and this could trigger off some thunderstorms possibly. This threat of thunderstorms may extend up into The Midlands but we will see.

Wednesday sees a rain front pass across Ireland overnight so by dawn it’ll be departing Leinster most probably. This rain front will push eastwards into The South West, West Wales and the west of Scotland through the morning intensifying as it crosses land mass. Further south this rain won’t make much more progress inland confining itself to Wales, The North West, The South West and Scotland. So England is set for a sunny day with hazy sunshine but much lower temperatures than Monday and Tuesday, down in the low twenties with a freshening westerly wind. That drop in temperatures will be felt everywhere with Ireland and Scotland now in the mid-teens, Wales and England, high teens to low twenties and significantly for the latter, much cooler nights to make sleeping more bearable.

Thursday sees a similar picture with rain fronts stacking off the west coast of Ireland and through the day these will make slow progress across the country, initially affecting West Munster, Connacht and Donegal during the morning but pushing inland later in the afternoon. For the U.K, we will also see rain across western coasts during the afternoon affecting an area from South Wales upwards. So England looks to stay dry on Thursday with again some sunshine and cloud and little in the way of rain away from western coasts. Scotland looks to have some pretty wet weather across the west and this will stay confined to the coast till the afternoon when it’ll move inland. Similar temperatures for all areas to Wednesday, mid-teens for Ireland and Scotland and high teens, low twenties for Wales and England. A fresh westerly wind again in situ.

So we close out the week on Friday with another very unsettled day, particularly across the west with some rain across Ireland, The South West of England and Scotland from the off. This rain could push into The North West and northern England through the course of the day and move along the south coast of England later in the afternoon into The South East on Friday evening. I’d say more risk of showers moving inland on Friday accompanied by a strong westerly wind but saying that many areas will stay dry and see some sunshine. Similar temperatures to the rest of the week with that strong to moderate westerly wind bringing a much fresher feel to the weather.

The outlook for the weekend isn’t great really unless you are fed up with irrigating and trying to keep your garden and lawn alive that is at home 🙂 So a heavy front of rain is set to push across Ireland and Scotland on Saturday crossing into The South West and Wales during the late morning pushing thick cloud before it. So the 2nd part of Saturday will see heavier rain for the west of the U.K moving inland as it does so with Ireland and Scotland hanging onto that rain for most of the day. (maybe lighter across the west of Ireland). That rain is set to cross the U.K overnight into Sunday with more rain likely through the day further inland across England a.m. with Ireland and Scotland missing the worst. Strong westerly / south-westerly winds likely over the weekend associated with that rain system and these will ramp up through Saturday before dying down through Sunday as the low passes through. Similar temperatures across the weekend to the 2nd half of the week.

Weather Outlook

So with the onset of unsettled and cooler conditions for the 2nd half of this week and weekend is this a fixed change or just a flip of a coin that will flip back to the hot and dry side next week ?

Well it looks like the latter from where I am sitting with the cooler front set to stay till mid-week next week before high pressure re-asserts itself from the west though not with the same level of heat as we have seen this week. I think after next weekend we will see a sunshine and showers scenario for the start of next week, more in the west and north rain-wise and staying cool with the winds more northerly if anything. Wednesday next week looks interesting and possibly another front of heavy rain pushing down across Ireland and into the rest of the U.K before high pressure spins us back onto a drier and warmer outlook.

Grass Agronomics

Ok since it’s my first blog of August we will do our normal look back at July GDD from a stats perspective.

GDD Comparison – Thame Location

Not surprisingly perhaps for a measurement that averages maximum and minimum air temperature, that our GDD figure for July 2018 was the highest we have ever recorded at 434, that’s 10% higher than any other July. Of course it doesn’t mean that we have recorded record growth because other factors will have come into play, namely moisture limiting growth and also the maximum air temperature being too high for the growth of some plant species, namely Poa annua, more on that later.

So the cumulative for the year looks not bad really and courtesy of July’s heat, 2018 is no longer a poor partner to the other years as it was before. In fact 2018 sits only just behind 2017 now as the highest GDD year cumulative July, what’s the betting that it doesn’t finish up as the warmest 2nd half of the year ever maybe ?

GDD Comparison – UK Locations

Ok let’s look at the GDD stats for the U.K and Ireland, accepting the fact that my weather station spends some of the time in full sunshine, so I get an ‘enhanced GDD’ figure.

Market Harborough is a lot of things but it isn’t the sunshine capital of the U.K, I think that title belongs to Eastbourne or somewhere similar. Incidentally my esteemed colleague Andy Russell hails from Eastbourne. It is rumoured that he only lives there because everybody else is older and that makes him feel young. (Luckily he never reads this far in my blog so I’m safe with this assertion :))

So pretty high GDD’s as commented earlier and you can see the difference a cooler airstream makes when we look at the Fife total and the Irish locations below. Rainfall-wise it’s a case of the ‘haves and have nots’ as commented in previous blogs with mid-teens for the month pretty standard and the higher totals for York and Okehampton courtesy of more rainfall during that cool and wet period at the end of July.

GDD Comparison – Irish Locations

Above are the stats for the various Irish locations and you can see the effect of a cooler westerly air stream that kicked in periodically during July across Ireland and is still in place today (same applies to Scotland). That said July 2018 will go down as a very good month from an Irish summer perspective and follows on from a very dry June where temperatures were very good but not as high as July.

Cumulative E.T Stress – Summer 2018

First off, I have updated the E.T vs. rainfall stats from The Oxfordshire (cheers Sean) so we can see how we are tracking. Now I know for the north and west (as per Meteoblue graphic model) you’ve had more rain and so this is largely immaterial but for England and Wales, the drought continues.

First up don’t they look very different graphs !

So if we look at the above stats taking the two-month period from June 1st to July 31st, in 2017 our soil moisture deficit was -113.9mm and in 2018 it is -225.1mm, a gnats whisker under double the moisture loss this year than last. Consider also that we have had some very hot days since and I think the E.T loss will be > -250mm over the last 9 weeks, that’s 10″ of rain equivalent !

That’s the result of 132.7mm of total E.T loss in July 2018 vs. 103.7mm in July 2017 for this location, an average of 4.3mm E.T loss per day. Of course it’s rained less this year as well with 16.4mm of rain in July 2018 vs. 62.2mm in July 2017.

Just while we are on the subject of stats from The Oxfordshire, the average maximum air temperature for July 2016 was 23°C, for 2017 it was 23°C and for 2018, 26.0°C. So the average maximum air temperature was +3°C, that doesn’t sound very significant does it but it is.

Consequences of prolonged E.T stress.

Growth Patterns

Well we know that during July in particular, the maximum air temperature has exceeded the limit for growth of Poa annua. Now it’s pretty tricky to find definitive data regarding what the ‘top out’ temperature for Poa annua is and maybe a little irrelevant because presumably a Poa annua biotype growing in the U.S will be different from one growing in say Dublin.

If I picked a figure I’d say that anything above 27°C has Poa annua on the back foot and whilst it won’t stop growing totally, there will be a marked drop off in growth rate. So I’ve plotted out the maximum air temperatures for the Thame and Dublin locations and looked at how this potentially could have affected Poa annua growth.

I’ve blocked up the days in red where the temperature was either close to or exceeded 27°C and you can clearly see the difference between the two locations. Now Thame is by no means the highest air temperature U.K location, so I’d say the stats for Surrey would have been even more significant. You can see the difference for the Irish location in that although they have had a very good June / July (depending on your perspective), the effect of maximum temperature on Poa growth was much less suppressive.

So during July at the Thame location, we have 18 days out of 31 when Poa annua was potentially growth-limited by maximum air temperature. It should also be said that if your surfaces have a higher organic matter content, they will have heated up quicker and so the effect would be even more significant.

I would also expect that if I ran the Growth Potential stats for July I’d see a reduction in G.P on these days. One of the big benefits of using G.P vs. GDD is that the equation takes into account the optimum temperature for cool season grass growth and produces a lower figure at higher air temperatures. This serves as a very good indicator of plant stress.

This feature of G.P is highlighted in the Meteoturf module this week with a lowered G.P for Monday and Tuesday courtesy of the high air temperatures and then an increasing G.P as the cooler air arrives mid-week. (see below)

What could be the consequences of this reduced growth potential ?

Organic matter production

Well less growth means less organic matter production for one and less nutrient use as well because the Poa plant isn’t developing new shoots, existing effectively in shut-down mode. It is also worth pointing out that with the high temperatures Poa annua switches over to survival-mode and that’s why we have seen another seedhead flush at the end of July / early August on fine turf.

From a practical perspective it would also mean less requirement for vertical aeration (verticutting) and topdressing (because there’s less growth to dilute). I always remember the sadly late Dr. James Beard commenting that a clubs maintenance schedule should not be fixed year on year in terms of aeration frequency, type of aeration, nitrogen input and in particular topdressing. It follows that in a growing year, there’s more requirement to keep organic matter under control by aeration and topdressing, whereas in this type of summer, that requirement must surely be less ?

August Aeration, root development and overseeding

Always a controversial subject for sure but one worth visiting….

Another consequence of the sustained temperatures will be a loss of rooting as the plant ‘sacrifices’ surface roots vs. deeper roots (if it has them). Now this last observation is purely anecdotal because I haven’t pulled plugs lately but I would expect root development to be pretty limited during extended periods of high air and surface organic matter temperature.

If this is the case then I think one of the benefits of August renovation is surely restoring some of that root deficit provided it coincides with cooler conditions. Another benefit is speed of germination if you are also using the opportunity to overseed as part of the aeration process. I put down some ryegrass seed on Thursday night and noted it had popped yesterday afternoon, that’s 3 1/2 days !. I presume bentgrass overseeding carried out at the moment would show a similar speed of germination.

Rainfall flush

Another comment that I have picked up repeatedly over the last week or so is the degree of growth flush experienced at the end of July once the rain arrived. Now I theorised about this last week in terms of N input in rainfall and possibly a pH effect as well.

Dr. Micah Woods kindly put me straight on the topic of rainfall pH, in that the pH of carbonic acid (CO2 + H2O) at equilibrium is around 5.6. Typically though I measure rainfall pH levels higher than this (depending on the type of rainfall and its source) so I can only surmise that the reaction between CO2 and H2O doesn’t reach full equilibrium and / or possibly other atmospheric constituents of rainfall are affecting the pH ?

And Fairy Rings….

Another consequence of the rainfall at the end of July was enhanced activity of the Fairy Ring fungus and a change in the ‘behaviour’ of the ring. So the feedback has been of Fairy Rings sitting there through July but becoming very active once we had rainfall. As we know, that rainfall was followed by some very high temperatures and in some cases, this has caused a loss of grass cover / bleaching effect around the circumference of the ring.

Why is this occurring ?

Well I think that the Fairy Ring fungi becomes more active with the advent of rainfall and elevated humidity and this activity extends to a higher fungal growth rate. The image above shows the effect of active Fairy Ring mycelium on moisture repellency in that more fungal mycelium = greater hydrophobicity.

So the areas became more water-repellent and then shortly after, air temperatures and E.T rates increased markedly, so the localised requirement for moisture increased dramatically. These areas are harder to wet up and so unless you were applying a good quality surfactant (with good organic matter wetting abilities) and irrigation close to the above sequence of events, you’re likely to see plant stress and potential grass cover loss. I think the above process happens very quickly by the way.

There has also been some research to suggest that a build up of ammonium / ammonia as a consequence of the Fairy Ring fungus converting organic nitrogen to nitrate nitrogen can be toxic to the grass plant. I would have thought that in hot conditions it would more likely be ammonia gas toxicity due to volatilisation. For this reason, light aeration to vent surfaces is beneficial as will be the application of a soil surfactant with Azoxystrobin and a biostimulant prior to the onset of rainfall (like later this week perhaps)

……………………………………………………

Ok that’s it for me today and for the next few weeks, I have to finish off my in-tray, tie a few flies, chuck my stuff together and ship out to AK. I hope the weather (and the bears) play ball (mental reminder not to watch The Revenant again on the in-flight movie!) and I look forward to catching you on the flip side late August.

All the best…

Mark Hunt

 

 

 

 

 

July 30th

Hi All,

Friday marked quite a transition  meteorologically-speaking, with some of the hottest temperatures I’ve seen on my weather station and car thermometer. At times we hit 36.5°C during Friday afternoon but the signs were already there that we were due a dramatic weather breakdown.

Returning from a mini-break in France, as we began our descent over northern France, I snapped this beautiful Anvil cloud or Cumulonimbus incus to give it its latin name. (Apparently the incus is an anvil-shaped bone in your middle ear, don’t you know, to further yours and my education this Monday morning :))

An anvil cloud originates from a thunderstorm and signifies the potential presence of hail, rain, thunder and some really strong updraft winds that my dad used to tell me are strong enough to break up a glider. Sure enough over the course of the weekend we saw some dramatic footage of hail, thunder and lightning, the arrival of rain and some pretty strong winds. Another thing I noticed from the plane was the thick band of smog / air pollution sitting over London, so those dissipating winds were welcome.

Of course again some areas got more than others with the east of the country, the north-west and Scotland getting dumped on. This radar image taken on Saturday evening shows the main pulse of rain moving across the east of the country though fortunately we saw a nice 10.5mm of rain over the last 3 days.

By Christ I think I wore out the rain radar link on my phone such was my desperation for some meaningful rainfall across Market Harborough. I caught myself repeating the words I hear so many times from you chaps…”The thing is here Mark, the rain just goes around us…..”

Yeah right…..

10mm odd is nowhere close to what we need but that and the lovely drop in temperature from the mid-thirties to the mid-teens had me scrambling to find another layer of clothing, such was the length of time since I needed it last…

So how are we set for this week, is that it rainfall-wise and is the heat that we know is set to build again looking long, medium or short-term ?

Image courtesy of NetWeather.tv

General Weather Situation

Well, it isn’t totally it for rainfall as we kick off Monday because this rain radar snap taken at 07.20 a.m. shows a raft of showers moving north-east across the U.K and Ireland. So definitely a day of sunshine and showers to kick off the week with the heaviest moving across the east and north-west of Ireland, north-west of England and East Anglia possibly. Winds will be moderate and from the south-west and temperatures will range from a high of 17°C over Ireland and Scotland to 23-24°C for southern England, in other words a nice day really.

Tuesday sees a new band of rain push into the west of Ireland but this one is much more likely to be north and west-orientated as we start to say goodbye to the low pressure that brought us such relief over the weekend. So rain likely from early doors in the west of Ireland but all the time the orientation of that rain is heading north and east into north-west Scotland by late morning. Further south we may just see some rain overnight and through the early hours for the far south-east of England but otherwise a dry, sunny day with varying amounts of cloud. The wind will be moderate and more westerly and temperatures similar to Monday.

Wednesday sees that low pressure still pushing in some thick cloud across mid / north Wales, the north-west and Ireland with some of it thick enough to generate light rain. We will also see some persistent rain across north-west Scotland, right from the off. Through the morning we will see temperatures rise as the cloud cover breaks but for Ireland the early afternoon will bring in some rain as well across the north, west and south. Elsewhere the cloud will build and keep the temperatures similar to the first part of the week, high teens across Scotland and Ireland and mid-twenties across the south of England.

Thursday sees that low pressure firmly pushed away to the north and this will allow heat to build from the continent so temperatures on the up with heat arriving in the shape of mid to high twenties across the south of England. It won’t be a totally dry day though because we will see a thick band of rain push over Ireland and into West Wales, The North West and Scotland through the morning with some locally heavy downpours likely. The demarcation line will be from The Severn Estuary to The Wash with thicker cloud and rain north of this and clear skies and higher temperatures to the south. Ireland looks to have a pretty grim day with thick cloud and rain throughout the day and the same for Scotland, The North West and Wales though South Wales may miss the worst of it. Much lighter winds on Thursday and more southerly in orientation turning northerly on Friday on their way to easterly for the weekend.

Friday sees a very similar picture with a thick front of cloud covering Ireland, Wales, The North West and Scotland. Again that cloud will be thick enough to bring some rain in places in the affected areas. Below this band of cloud we will see the sun break through and push temperatures up into the high twenties across The Midlands and south of England and East Anglia. As we progress through the afternoon, the thicker cloud layer will start to dissipate across the west and north to give more in the way of sunshine and better temperatures though Ireland may only clear in some north and western areas. Light westerly / north-westerly winds for the end of the week.

The upcoming weekend looks pretty nice really with high pressure in charge and warm, dry conditions and cloud cover burning off through both days. (I say nice, it’s not my nice, I like wind and rain for fishing 🙂 )

Temperatures up into the high twenties can be expected across the south of England but I reckon the warmest areas will be South Wales and The South West with the possibility of hitting thirty degrees here. This heat though comes with the threat of thunderstorms on both days as we approach late afternoon / early evening. Ireland will see some of this heat as well especially on Sunday with temperatures in the mid-twenties but they’ll be rain around as well, particularly across the west. Scotland will have a cooler side of the coin, still thoroughly pleasant though with some rain over the north and west on Sunday.

Weather Outlook

So with high temperatures forecast for this weekend, are we looking at another long dry spell across August or is the outlook less certain ?

Image courtesy of Unisys Weather

Above is the projection from Unisys Weather for next Thursday (10 days time) and as you can see we have a low pressure pushing down across the U.K bring cooler temps and no doubt rain as well. So looking to next week I think we will take the weekend heat into the start of next week but right from the off we may see the beginnings of a breakdown across the west of Ireland as the low pushes in. The settled conditions will probably persist further east through Tuesday but all the time we will see more unsettled conditions come into the west and move slowly eastwards so I expect by late Tuesday / early Wednesday we will see cooler temperatures and a more unsettled picture across the U.K and Ireland.

The usual caveat applies, that of the low winning the day vs. the resident high pressure so please don’t shout if I’m wrong. For the 2nd half of next week it looks like strong westerly winds and unsettled sunshine and shower conditions. Not great if you are on your summer holidays but I don’t think it’ll be a permanent switch with high pressure possibly following on from this.

Agronomic Notes

Ok, so we have had a really extended dry spell, my weather station recorded 57 days since the last meaningful rainfall fell across Leicestershire on the 30th May with only 1.8mm recorded in June and the same in July though that might have been because I hand-watered my rain gauge trying to keep my newly planted garden alive !!

The weekend didn’t just bring rain, it also brought humidity and that means we are likely to be seeing a peak in disease activity as we go through this week rcarrying over from the weekend.

You can see the effect on humidity and temperature on the stats from my Netatmo Weather Station below….

It’s likely that your turf could potentially show a number of pathogens over the coming days if it isn’t already. The good news is with warmer and drier conditions coming this week, we should see some of these disappear as quickly as they come, though as usual with everything in life, there will be exceptions.

It is likely that pathogens like Microdochium nivale may persist across the geographical areas that will experience thicker cloud, rainfall and high humidity through this week, so that’s Ireland, Wales, The North West and Scotland in particular. Where we see drier and more settled conditions I think it’ll fade as quick as it came in.

I think as we approach August and in some areas carry over humidity / rainfall we will see increased pressure from Dollar Spot as well.

Anthracnose Foliar Blight

One of the pathogens that is likely to be more visible is Anthracnose Foliar Blight which has had nearly two months to sit within the grass plant as a biotroph (resting state within the plant). I received a good few reports of activity over the last 3-4 weeks and I expect this will increase as the arrival of rain stimulates growth, especially on greens.

The appearance and growth of grass after summer rain is always far better than after irrigation, part due I think to the presence of nitrogen in stormy summer rain and part to the pH of the water, with many mains water supplies in the U.K and Ireland, high in pH and bicarbonate. Rain typically falls as a weak acid (Carbonic formed from a reaction between H2O and CO2) at a pH of 6.7, but can be much lower depending on its source.

I’ve already had a number of reports of a growth flush on greens after the rainfall and what we may see associated with it, is an increase in Anthracnose Foliar Blight activity. This occurs because the newly stimulated grass plant tries to grow with a compromised shoot and root system and cannot uptake sufficient water and nutrient through damaged structures. The grass plants photosynthetic capacity is also affected with Foliar Blight.

So if you are looking at something like the above, what’s the best way forward ?

First off we should consider if applying a fungicide will benefit us ?

In my humble opinion I think the only benefit of applying a fungicide with active Anthracnose Foliar Blight is to ring-fence the currently healthy plants. I say this because we need to understand that the stage of disease present in the affected plants is already far too late to be corrected by a fungicide application. Once you see the above symptoms on turf, you’d also see blackening on the base, crown and leaves (sometimes) of the affected plants if you looked closer.

The blackening is attributable to structures called Acervuli, which are the fruiting bodies for this pathogen and produce asexual spores. These spores are raised aloft so-to-speak on hair-like structures called Setae and are then transported away from the affected plant to begin the cycle again.

So in plain English when we see symptoms of this disease on the turf surface it has already gone through its whole life cycle and that’s why fungicidal applications won’t correct the visible symptoms. There is therefore no effective chemical curative control of Anthracnose, whatever the rep that comes down your driveway says. Everything has to be aimed at preventing this occurring in the first place.

Another feature of this disease that I have noticed is its ability to look like it is increasing even when you have applied a fungicide and have ticked all of the BMP boxes. This is I think because within your grass sward they’ll be plants not yet showing leaf symptoms but with the pathogen present and so they’re already on their way to checking out.

So what’s to be done ?

Well I think the best course of action is to carry out renovation and introduce new seed to the affected areas to try and regain sward integrity. I know some people state that they ‘like’ Anthracnose because it takes out Poa annua but the same people should be mindful that unless you establish another grass species in the voids created by this disease, the only thing you’ll be staring at in the late autumn is the ultra-invasive, clumpy, annual Poa biotype, which is arguably a worse grass plant than the perennial Poa it replaced 🙁

Nutrition-wise you should still be aiming for the Rutgers baseline levels of 3.6% N and 2.0% K but often a light-rate, granular fertiliser accompanying the renovation and overseeding does no harm at all in pulling the surface together and creating an integrated sward.

Remember also that all the research shows that acidifying nutrient-sources tend to favour Anthracnose development and that more basic fertilisers like potassium nitrate do not, the exact opposite to Microdochium nivale. So for this reason think about your choice of granular fertiliser if you decide to go down that path.

If you’ve managed to come through 2 months of stress with surfaces that are currently unblemished, then you are due a pat on the back, but remember summer isn’t over yet 🙂

Ok, that’s it for this week, next week’s blog will cover my usual monthly summary for our hottest July on record and it will be the last for a few weeks as I depart for my Alaskan fix of all things wilderness, no Wifi and no phone network 🙂

All the best.

Mark Hunt

 

July 23rd – Mini Blog

 

Hi All,

As I sit here in the beautiful Cevenne area of France watching Swallow Tail and White Admirals float around the hotel garden and the odd Griffin Vulture soar effortlessly above me I wonder how come they have such diversity of nature here and we do not. Obviously they have a lot fewer people and this area of France is characterised by Le Causse, consisting of limestone canyons and ancient grassland with little intensive agriculture so nature has a much better chance to survive and prosper. Their climate is also conducive with hot summers and the odd frequent thunderstorm to keep things ticking and looking green.

Looking green wasn’t in my mind as I gazed down on the parched landscape of Cambridgeshire from the Ryanair flight. Accepted that it is harvest time but all the same most of any grassland looks toasted.

Also available in green

Of course some of us got a good dollop of rain on Friday and early Saturday as a band of showers moved diagonally down across the U.K.

It was though sadly a case of the ‘haves and the have-nots ‘ because whereas just down the road picked up 30mm of rain, we had a passing shower that didn’t even register on the weather station other than to pick the humidity up for a short time. So so bloody frustrating.

Now most of this rain will run straight off drought-affected areas because the surface is pretty hydrophobic now and it’ll take weeks of steady rainfall to wet up the profile again, but it sure was welcome for the areas that got it. For the areas that didn’t, it’s business as usual I am afraid with the calendar flipping towards the 9 week mark without meaningful rainfall. taking us into uncharted territory for some.

General Weather Situation

So as this is a mini-blog and the time for me to start walking in the mountains approaches I’ll summarise the week we have in store.

The low pressure which we really needed to sink south to end our sustained hot spell will stay off the north-west coast of Scotland and that’ll mean we don’t get the breakdown to cooler and unsettled conditions further south I am afraid. The demarcation line with cooler weather to the north will lie from North Wales across to The Humber and hot, dry conditions further south.

Monday sees a weak rain front already crossing the north-west of Ireland, The Isle of Man and pushing up into south-west Scotland and the Northern Lakes. There’s a chance of some light rain prevailing into west and north Wales overnight but I can’t see it making progress inland so warm and dry weather is set to continue down south. The slight saving grace this week will be more in the way of cloud cover further south so less direct sun hours and a bit more shade, nevertheless it’ll be small compensation with temperatures touching 30°C or higher in the south of England and nights remaining hot. (Oh to be a fan salesman at the moment :))

The cooler and fresher weather this week will I am afraid stay further north and west as Scotland and Ireland sees high teens and maybe just touching the low twenties on occasion. For these areas expect to see rain pushing through on Wednesday night / Thursday for Ireland and Thursday night / Friday for Scotland.

There is a chance that we will see rain push into the south coast on Thursday night and this may extend northwards into The Midlands and north of England through the course of Friday in the shape of thunderstorms and snap showers but let’s wait and see if it comes to pass. So hot and dry for this week across The South West, Wales and England with heat building through the week and then a potential breakdown to cooler weather on Friday  and the weekend with temperatures dropping to the low twenties.

Weather Outlook

If you look at the image above which is a projection for the 2nd of August (and so carries with it a good deal of uncertainty) you can see we are set in a similar pattern to this week in that the west and north will enjoy cooler and more unsettled conditions but the south and south-east remains dry. So I think we will see a similar pattern to the last week, heat building and then a breakdown with some thunderstorms further south and then cooler and fresher weather for a time before heat builds again. Hard work if you miss that rain 🙁

Agronomic Notes

Continuing E.T Stress

Above is the graph up until yesterday from The Oxfordshire at Thame. You may just make out they got a sneaky 6.8mm of rain on Friday night (you kept that quiet Sean :)) but nevertheless the E.T loss is just below 200mm since the start of the dry spell, that’s 8″ in old money and one heck of a lot of water to replace.

A lot of facilities are starting to look nervously at their water reserves and make decisions on frequency and amount of irrigation available for turfed areas with tees dropping down to every other day and many courses that have fairway irrigation now opting not to use it in order to prioritise greens.

Watch your Growth Potential for signs of increased plant stress

Now you are probably sitting there thinking I don’t need to look at a chart Mark because my turf is already telling me it’s stressed but your projected G.P forecast provides some clues about how much stress the plant is under.

Looking at the Meteoturf forecast for this week we can see a suppression effect on the Growth Potential from Monday to Thursday inclusive before the arrival of cooler weather drops the stress and increases the growth. So this means for this location, Market Harborough by the way, we can expect high levels of stress this week before some respite at the weekend.

During these periods of high temperatures and elevated stress, less is definitely more. This applies to many things including irrigation (it’s quite possible to over-water as well as under-water during hot dry spells) and any turf maintenance must be thought about carefully. Switching to solid rollers on greens mowers to reduce turf stress (if budgets allow) is a very practical way of helping the grass plant out.

USGA Record

We don’t have to reinvent the wheel either as our American cousins have managed high temperature turfgrass stress for years and we can learn from them. To this end The USGA Green Section Record is a vital and so so useful source of information, you can subscribe free here

Can’t remember the last time we saw a dew like that

I picked up a couple of gems in the latest USGA record this week , one pertaining to just this subject area from the north-east of the USA where heat has arrived after a wet and cold start to the spring (sound familiar by any chance ?) and the other talking about using boomless sprayers on hard to reach areas like bunker banks.

You can read about stress management during high temperatures here and also about boomless sprayers here

Timely PGR applications are now showing their worth on outfield areas

Now PGR applications on outfield areas aren’t understandably on most peoples radar with the current conditions because the weather across central and southern areas is working as one big PGR and turf is stressed. I mention it though because it does strike me how well some turf areas are holding up that had a high rate of PGR at the end of May. Lucky timing maybe but if trends continue in terms of a warmer climate (and every sign is that they will) then this is something that we may look to build into programs going forward.

Anthracnose Foliar Blight

For areas that did receive rain and therefore humidity at the end of last week I expect to see an increase in the prevalence of this turf pathogen. Dollar Spot as well will make an appearance as both diseases are stress-related. Already I have had a number of Anthracnose Foliar Blight reports from around the country so it is definitely a cause for concern…..

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Ok that’s it for this week, a quick Café au Lait and it is on with the walking boots 🙂

All the best for those of you still enduring the heat and lack of water, fingers crossed for another end of week breakdown.

Mark Hunt

July 16th

Hi All,

After another scorching weekend, things are due to settle down a bit heat-wise as we see a slow breakdown in the weather. Some areas saw their first rain on Friday evening for 7-8 weeks with torrential downpours across London depositing 50mm in just 2 hours. Elsewhere we have seen rain across Ireland, the north-west of England and Scotland with a vertical band of rain slowly moving across the west side of the country this morning. (It looks like St David’s, Pembrokeshire is getting a proper hammering as I type this at 09.42)

Central and eastern areas though remain parched.

The big question for many will be “Will I see any rain this week ?” and the answer of course will depend on your location. The areas most likely to receive rain this week will be in the north and west and so the south and especially The Midlands may see little more than the odd shower I am afraid. That said the end of the week probably holds the best chance of some sneaky un-forecastable rain for the south of England.

We will see a lot more cloud than of late across the U.K and that’ll help the job temperature-wise with some cooler nights to boot but the breakdown will be slower than first thought because the low pressure is staying up north.

Not every plant dislikes the current weather though, I’ve walked through this Maize crop every week since it was late-planted in the spring and can’t believe how fast it is growing…

General Weather Situation

So we start Monday we that band of rain (/) moving across country and currently affecting the west side of the U.K stretching up from Cornwall through West Wales, up to the north-west of England and east of Scotland. It is a narrow band though and that means it is likely to fizzle out before reaching central and eastern areas which is a pity. As that rain tries to move east it’ll push some cloud up before it and that cloud will keep the temperatures 4-5°C lower than yesterday for The Midlands. Ireland will also see those showers cross-country through the day after a similar day yesterday and much cooler temperatures, down in the high teens. Further south away from the effects of that rain front we will see another hot day I’m afraid with temperatures pushing up into the high twenties. Winds will be light and westerly / north-westerly.

Onto Tuesday and that departing rain front will leave some thicker cloud across the east coast of England and in general we will see a cloudier, cooler day with temperatures down in the low twenties due to the wind aspect and cloud cover. There’s a risk of some showers across the north-west and north-east of England and may be a snap one further south. Ireland looks to have a similar day with any showers confined to Donegal and the north-west. So cooler than of late with Ireland and Scotland in the high teens and low twenties further south courtesy of that north-west wind.

Wednesday sees that north-westerly wind drop and swing more westerly so temperatures will rise again towards the mid-twenties in the south of England. Still plenty of cloud around, some of it quite thick again across the east of the country with Wales and the west coast perhaps seeing the best chance of the sun. Ireland looks to stay cloudy all day but dry. Similar temperatures for Ireland and Scotland in the high teens through to mid-twenties for central and southern areas.

Thursday sees the wind do a full 180° swing down south to blow lightly from the south-east and that’s one of the reasons why any rain later in the week will struggle to affect the south of England. Up north we will see that north-westerly wind push back in, light to moderate and that’ll swing cloud cover across the U.K and Ireland with temperatures dropping a degree or so across Scotland and Ireland as a result. So warmer where you get that wind direction change across central and southern England with temperatures once more in the mid-twenties, cooler further west where you keep that north-westerly air stream.

Closing out the week on Friday we see a rain front push into north-west Ireland / south-west Scotland overnight and this will move in  south-easterly direction across Ireland pushing thick cloud before it. Now currently the odds are that this rain front will not make much progress into Wales and the north of England but it’s been changing on a daily basis so we’ll see. Ireland and Scotland look to be dull with plenty of rain for Ireland but further south it’ll be hotter because the wind will push from the south, so a hot dry day with temperatures in the mid to high twenties to finish off the week across the south of England.

So what’s the outlook for next weekend ?

Well a lot depends on where the winds coming from but currently the odds are that the wind will swing round to the west / north-west across all areas and that’ll push in a cooler, fresher air stream across all areas dropping the temperature significantly on Saturday with high teens likely across all areas. A real north / west / south divide on Saturday with Ireland, Scotland, the north-west and north-east still sitting under that thick cloud so cool and dull here vs. hazy sunshine and cloud further south. Sunday sees warmer air from that close-by, Atlantic high pressure push in over Ireland and the west raising temperatures up to the low twenties for Ireland and Scotland and mid-twenties further south.

Weather Outlook

So next week looks to start warm enough after a hot Sunday but if we are to see a real breakdown of this continued dry spell for many, next week will be the clincher. That’s because we have a deep low pressure sitting north-west of the U.K that through next week is projected to sink down and introduce cooler and more unsettled conditions through the week, starting with the north and west on Monday / Tuesday and then extending south to all parts later in the week. This transition is key because if it occurs it’ll introduce a westerly air stream which will end the blocking action of the Atlantic high and allow low pressure systems to feed in.

Now I know when we are going through this process it is a bit like waiting for a delayed train, every time you look at the timing board it’s delayed a little bit more so you wonder whether it will ever turn up.

Honestly-speaking,  this could be the case here, we could have a re-run of this week with the low pressure staying further north and only bringing cooler weather / rain to the north and west, whilst the south and east bakes. Part of the problem is that we are sitting here in the middle of July so we still have heat potential to come, whereas in 1976, this process occurred in late August. I could counter that by saying the run of August weather we have had of late would point towards a greater likelihood of unsettled conditions than heat. Time will tell.

Agronomic Notes

Dormant Turf

Pic courtesy of West Lancashire Golf Club

So in some areas we are into week 8 now without appreciable rain and the effects of continual E.T stress are plain to see.

Above is a pic from the north-west of England, an area normally associated with anything but a shortage of rainfall. This course got 15mm of rain late last week and I think I’m right in saying it is raining there now.  It will however be a while before the grass comes out of dormancy and begins to respond to the change in moisture status and fresher conditions. Brown grass like this is at its very simplistic, exhibiting nitrogen deficiency, because with extremely low levels of soil moisture the grass plant is unable to uptake nitrogen and so sacrifices its leaves to protect the part of the plant that ultimately determines its fate, the crown.

The crown is where it all goes on in the grass plant because it is here where cells divide into root or shoot cells and during spells of prolonged drought this is the area that the grass plant prioritises. So when you are looking at an area of turf like the one above an obvious question springs to mind “Is this turf dead or is it dormant ?”

The survival of the grass plant crown is not only a function of moisture availability, its place within the turf canopy is key and that’s where things like surplus organic matter come in to play. Areas of turf that contain excessive organic matter will cause the crown to be elevated above the soil layer and resident within the surface organic matter layer. This in itself drastically lowers the ability of the plant to survive. Firstly organic matter heats up far quicker than soil and so areas of thatch will literally bake off, dehydrating the crown and killing the plant. An elevated crown is also prone to damage by wear and tear being situated above the soil layer so turf that is dormant with an elevated crown will show more wear damage and soon take on a black appearance as the grass begins to degrade.

Image courtesy of Bruce Clarke Rutgers University

More of a golf green scenario for many but the level of topdressing integrated within the profile will also dictate the grass plants ability to withstand this type of prolonged heat and ultimately survive. I’ve used this picture before but you can clearly see how the crown of the grass plants (in this case Poa but it applies to any species really) on the right are sitting down in the rootzone and so protected from the worst of the summer heat and wear and tear to boot. The plants on the left taken from an area which has received little topdressing are elevated and right in the firing line unfortunately.

So one thing you may notice is that your thatchiest areas on the golf course / sports pitch, etc won’t recover once rainfall re-commences and this is because the crown has died and is starting to degrade. The images above show a healthy white grass plant crown above compared to a tan-coloured crown that is starting to degrade. (in fact you can see fungal hyphae on the crown)

So should you apply fertiliser to drought-stressed turf ?

It may seem a daft question but in some instances (domestic lawn care for example) this one comes up a lot. It really depends on the type of fertiliser because depending on how much rain falls when the drought breaks, you could make the situation worse my desiccating the plant further as moisture is drawn out of the plant towards the fertiliser.

The amount of desiccation is dependent on the osmolarity of the applied fertiliser (whether it be liquid or granule) and this is a function of the salt index of the fertiliser. (the lower the salt index, the lower the osmotic draw from the plant)

If we have plenty of rain then this won’t be an issue but the smart money is on waiting for moisture levels in the rootzone to re-establish and the grass plant to begin growing again before applying fertiliser.

E.T Stress – Where are we now ?

At the end of June I put together two graphics comparing 2018 y.t.d with 2017 in terms of rainfall, Demand E.T and soil moisture deficit.

Two weeks on I thought I’d re-visit this to see how we are doing…

So in the above graph from 2017 you can see we had a period during June for about 16 days when no rainfall was forthcoming, we then got rainfall on the 27th. It went hot and dry again and E.T ramped up but on the 12th July we got rain again, that’s a gap of 14 days. So in terms of crown hydration the grass plant kept getting a little water every fortnight to keep it healthy and viable.

Overall the theoretical moisture deficit from June 1st, 2017 to July 15th, 2017 was -116.1mm

Compare that with the scenario below for this year ;

Quite a different shaped graph with no rainfall since June 1st and consequently an ever-increasing theoretical soil moisture deficit, now at 177.4mm up until the 15th July, 2018, that’s over 7″ in old money.

As mentioned before this cumulative plant stress is likely to result in some plants in less than optimal conditions checking out depending on their crown and of course root status.

Coming back to the beginning of this blog, the reason that maize is still looking good is because it has a very deep root system and so finds it easier to maintain plant moisture status. The same is true of grass plants but of course the functionality of the root system is dependent upon so many other factors aside from just plant species.

I once saw an autumn over-sown Fescue / Rye fairway go under drought stress the following summer and I expected to see the Fescue survive and the Ryegrass check out. When I visited the course, the exact opposite was true, the Fescue was dead and the rye alive.

Upon examination the previous autumn sown rye had got its roots down through an organic matter layer present in the rootzone and into the clay beneath and so had survived whereas the less vigorous Fescue had not penetrated through the organic matter layer and its roots had dehydrated to a point where the whole plant died. Not what you’d normally expect species-wise but an illustration that the local environment (rootzone characteristics, organic matter content, root depth) has a big say in what happens to a grass plant in a severe drought scenario.

Humidity = Disease

One last point is that ‘if and when’ your site does finally receive some welcome rain it may not all be good news. The increase in humidity is sure to kick off some of the more stress-related turf diseases like Dollar Spot and Anthracnose. Be on your guard.

Ok, that’s me for this week, I am on my travels next week but I’ll still be taking time to put the blog together as I know next week is critical from a weather perspective. In a little under a months time I’ll be off to the Alaskan Wilderness once again and taking a sabbatical from the blog till late August as mercifully Upper Camp on the Kanetok River has no WiFi, no phone reception, well nothing really except Tundra, Salmon, Dolly Varden, Trout, Bears and lots of Mozzies 🙂

All the best…

Mark Hunt

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

July 9th

As we now enter week 7 without meaningful rain and an E.T loss over that period that runs to 6-7″ (150-175mm) of moisture, the cracks are starting to show in more ways than one.

As I walked through the parched countryside yesterday I mused that not so many months ago these same paths were almost unwalkable, such was the amount of rain we had endured, now I was staring down at deep cracks in the Leicestershire clay. It’s an oft-used term but we seem to lurch from extreme to extreme weather-wise nowadays.

The last drought / heat of this magnitude was in 1976 and showing my age I can remember it well as the first year of my teens. (showing me age now I know)

Back then it was warm and dry from January onwards, so we went into the summer already on the back foot water-wise. Rivers and lakes dried up, canals became unnavigable (and crystal clear because of the lack of boat traffic Mike :P) and spring crops failed in the fields. That year the weather broke in August and it was quite amazing how quickly things turned around and life returned to normality, the drought quickly forgotten.

2018 doesn’t equal 1976, because we had such a wet run up to proceedings and till now that’s been our saving grace from hose pipe bans and golf courses being treated like a 2nd-rate  citizens when it comes to the pecking order of who can water what. Plants are struggling though, whether it be on the golf course, in the garden or crops in the field. You only have to look at the pitiful state of late-sown spring crops or the amount of re-growth after the last silage cut to see that. Water is a resource that is no longer a given.

Last week at the ETS Conference, the question was posed a number of times…”If our water allocation was cut by 25%, could we survive ?”…I think we could and in the future it is likely in some areas of the country to come to that, such will be the competition for this resource from building and infrastructure.

We as an industry would change and adapt, just like they have in other areas of the world where water scarcity threatens. Management practices and indeed expectations would also have to change from our customer perspective, the latter may be a harder nut to crack judging by some of the comments I hear from you guys in the industry. Of course this thought process will likely disappear from the agenda when the weather breaks and we turn our focus onto the next challenge to our golf course, football pitch, racecourse (delete where applicable), most likely how to implement a satisfactory drainage policy in a wet autumn 🙂

So onto the general weather situation and has that whiff of change I mentioned last week gathered momentum or disappeared and will this be my Michael Fish moment when I forecast exactly the opposite of what will indeed occur  (Thanks Adam :))

General Weather Situation

So Monday starts off pretty much as we left off the weekend, hot dry and sunny for England and Wales with possibly more in the way of cloud over the north and east of the U.K. Quite a difference in temperature though between Scotland and Ireland sitting in the low twenties (lucky you) and down south in England and Wales where we are looking at high twenties again I think depending on your location, wind and cloud cover. The wind will swing round to the north-east through Monday and freshen. That’ll knock the temperatures back a tad in the evening and perhaps bring cooler and more pleasant night temperatures to aid a better nights sleep. (some hope)

Tuesday sees a thicker layer of cloud cover the U.K and particularly over Scotland where it may be thick enough for some mizzly drizzle in places. Down south we will see this cloud cover slowly burn off aided by a freshening north-easterly wind but across the west coasts, Wales, Ireland and Scotland, it may well prevail and that’ll keep the temperature nipped down. In fact for most of the U.K we will be noticeably cooler on Tuesday with that freshening wind keeping temperatures down in the low twenties, a pleasant transition and a cooler night to boot.

Overnight into Wednesday and we see a rain front push into Donegal and the north-west of Scotland but it’ll be short-lived and soon move off again. Again we will see plenty of thicker cloud come off The North Sea and again it’ll hug some westerly regions, particularly South Wales and the east coast of Ireland. That north-easterly wind will be a tad lighter on Wednesday so I think similar temperatures to Tuesday, around about 20°C for Ireland and Scotland and a couple of degrees higher for England and Wales. Remaining dry but again a cooler night for which to contemplate the telly and the next England World Cup match. Have to say, great to see the return of team spirit to our national side, a lack of prima donna’s and the lads enjoying the challenge, at last something positive to focus on amidst the political turmoil that is unfolding currently 🙁

Thursday sees a weak weather front push into Ireland and the west coast of the U.K bringing the potential for rain from The South West up through West Wales, The North West and south-west of Scotland. (Did I say rain ?) Inland from this we will see the familiar pattern of cloud cover burning off and a dry, bright and sunny day for most of England and Scotland with the exception of the west. Ireland looks to be cloudier with perhaps a chance of some rain across eastern counties through the 2nd half of the day. With the wind taking on a more easterly aspect I expect temperatures to ease up a degree or two towards the mid-twenties for those of you seeing the sun, low twenties for Scotland and maybe just the very high teens for Ireland under that thicker cloud.

Rounding out the week on Friday and that familiar pattern again of thicker cloud burning off but I’d say it may be persistent in some central and western areas of the U.K and Ireland. Similar temperatures to Thursday but they’ll start to climb for the weekend so maybe a degree or two up and warmer night temperatures return 🙁 Remaining dry.

So the weekend looks like being hot again although I’m not 100% on this because I think by the 2nd half of the weekend (that’s Sunday to you and me) we will see the wind edge westerly and bring cooler temperatures, initially to the north and west but by the 2nd part of Sunday, hopefully further south, but this may not occur till Monday perhaps. Now this change in wind direction would be one piece of the weather-breakdown theory that may (or may not) unfold over the next week or so and a crucial one in my books. So hot, sunny and dry for the weekend but I’ll be looking for that wind swing on Sunday. One final point is that if we do see cooler air come in, then the beginning of the breakdown will probably be accompanied by thunderstorms.

Weather Outlook

And here I fear a Michael Fish moment looms…..

So looking at Unisys weather the outlook is for the jet stream to drop south and allow low pressure to move in during the early part of next week and move us into a phase of cooler and more unsettled weather with rain. The cooler and unsettled conditions will affect the north and west first before pushing south later into next week.

There I’ve said it, that’s my take following on from my contentious ‘whiff of change’ comment in last Wednesday’s blog…

In order for our weather to change properly we need a number of things to fall into place, with the position in the jet stream the key piece in the puzzle. Since the beginning of June we have sat under a peak in the jet stream that allowed hot air to form below it and a succession of Atlantic High pressure systems to dominate. So the rain has been going up and over us. Iceland is having its wettest summer for years with less than a week of dry days since the middle of April. You’ll also have seen the weather in Russia, cool and unsettled with plenty of rain. That’s the flip side to our current weather coin.

Both Unisys and Netweather show the jet stream dropping south at the end of the weekend and that’ll allow low pressure systems to do likewise with the north initially affected and hopefully further south later into next week rain-wise.

Now there’s a big caveat with my prognosis and it is this….I can’t see a consensus out there from a weather projection perspective so this may well turn out to be a Michael Fish moment on my behalf but the cards in my hand say unsettled conditions are coming so they are the ones I’m playing…..I’ll see you and raise you ten 😛

Agronomic Notes

So if the prognosis is right, we have another week of dry, bright and settled conditions, cooler than of late with that change in wind direction and that’s reflected in the projected E.T figures for this week.

For my location the projected E.T loss is 16mm over the next 7 days, whereas last week it was around 26mm, roughly a 40% reduction.

Now last week I tried to explain the relationship between E.T and irrigation demand (badly), but the USGA Record do a much better job with this article on E.T-based irrigation scheduling here

Now of course some of you might say that’s all well and good but how do I measure E.T ?

Well you can purchase a dedicated E.T Gauge / Evapotranspiration Simulator, but that’s the thick end of $400 bucks for a posh one. Alternatively you can get a weather station that also measures E.T (Netatmo doesn’t by the way) or you can use a weather forecast system that includes projected E.T rates as part of the forecast. As you can see from the above, we include this feature as part of Weathercheck. In the U.S, where E.T is more relevant for turf and crop management systems, they have a national network of weather stations that you can check to find out the current E.T rate for your area (or an area close to you).

I looked at Weather Undergrounds network for the U.K and Davis Weatherlink and only found the odd PWS that broadcasts E.T data so clearly we are behind the curve here. The problem here though is that even a forecasted E.T figure will only be an approximation and across your site you will have big variations. For example, a golf green in full sun and with an open-aspect will run a much higher E.T than a green that is sheltered from the wind and say in shade. In turn this means that the former green will run higher E.T’s, higher plant stress levels and so be more susceptible to some of the stress-related diseases like Anthracnose and Dollar Spot to name but two.

Aeration and Stressed Turf

Clearly during periods of weather like this, aeration practices have to be well thought through and sometimes ‘less is more’. If we have grass that is on the edge of wilt for 10 hours of the day (or longer) then cultural processes that impact the leaf like verticutting / grooming, topdressing and the like isn’t in its or your best interests.

Switching to smooth rollers during stress periods has always been a big win in my mind (if budgets allow) because they put less stress on the plant but what of processes like solid tining or even using compact vertidrains with narrow tines.

Again the USGA-Record (a brilliant resource that is free to all) comes to my rescue with a nice article on mitigating summer stress. In it you’ll see there are two sides to the aeration coin. You can read the above article here.

I think this is where we need to read our turf and the weather closely because in these cooler periods of weather and particularly when we have cooler nights, then using small diameter solid tines to vent surfaces has a number of benefits. Firstly, one must remember it is possible to over-water rootzones and effectively you end up causing more harm than good. A saturated rootzone has low oxygen availability and of course as that water warms, it’s ability to hold oxygen decreases even further. So effectively we are simmering our roots if we have over-watered an area and depriving them of oxygen, cue a stressed plant. So water management and more specifically water movement becomes key and critically we need to maintain a balance of air and water in the rootzone and that’s where venting comes in. It allows areas to dry down more effectively, it increases oxygen availability and of course vents potential harmful gas build up. So this week with that cooler period mid-week would I think be a good time to vent your greens.

I have probably related this story before but I think repetition is no bad thing in this case….

During the summer of 2014, we had very high levels of Anthracnose in the UK and I visited one end-user who was particularly badly hit. Now 2-3 weeks previous to the Anthracnose rearing its ugly head, I could see the greens were on their limit from a nutrition and stress perspective and was concerned that we were staring potential Anthracnose issues in the face. That concern was well-placed because indeed we saw the disease affect most greens. I say ‘most greens’ because two were largely unaffected and when I sat down with the Superintendent to chat it through I tried to focus on what was different about those two greens management-wise. We went round the houses as usual but eventually I think we nailed it. Those two greens had been vertidrained in July with a compact vertidrain down to 8-10″, they were the only two as it happens and the benefits to me in carrying out this work before Anthracnose reared its head were clear to see.

As the referenced article above states, less can be more when it comes to aeration during stress periods and I can’t stress this enough however if you are keeping your turf on the healthy side and the weather plays ball then solid tining / vertidraining with small diameter tines in the right circumstances can pay big dividends.

Ok, that’s all for this week and time will tell if this is or is not my ‘Michael Fish moment’, that said Meteoblue’s forecasted max temps for Sunday have just dropped 2°C, so you never know.

Have a good week, keep up the sunblock and good luck to England on Wednesday night, we will all be rooting for you (well everyone except The Celts that is 🙂 )

All the best

Mark Hunt