Monthly Archives: May 2018

May 29th

Hi All,

Well what  a Bank Holiday that was meteorologically !

The most amazing light show I’ve ever seen on Saturday night with constant lightning, thunder and then torrential rain.

Sunday saw some of the most active storm cells I have ever witnessed I think across the U.K and they were sparked off uncannily along the line of the M1 motorway and across London giving weight to the theory that hot concrete, hot cars, buildings, distribution warehouse roofs, etc act as the initial vectors for storms. (In the image below, the M1 motorway is directly under the path of the storms shown on the Netweather radar)

Image courtesy of and my I-phone

Some parts of Milton Keynes received 75mm of rain over a very short period and Birmingham once again was hit by flooding when 58mm of rain fell in one hour. It is no coincidence then that sometimes cities where we have lots of hot concrete, shiny roofs and traffic / hot cars are the focal point of these storms.

I’ve put together an archive of the lightning strikes over the last 3 days so you can see where it tracked ;

Ireland got its fair share of storms across the east and south-east by the looks of it. At the other end of the country, Scotland enjoyed beautiful Bank Holiday weather with temperatures on Monday tipping 30°C, so Smithy you owe me a Big Latte in Betty’s now matey 🙂

So after that tumultuous weekend, what have we got coming this week ?

Rainfall Forecasting

Before I give you this forecast, please remember my enduring caveat regarding continental rainfall and its unforecastability. No one forecast the deluges of Sunday, not even close. Here in Market Harborough we were forecast 15mm on Friday and got 21mm, then another 13.5mm on Saturday night / Sunday which wasn’t forecast and then we were forecast to get 14mm on Sunday and we got 1mm. My advice always is look at your rain radar, back click / forward click to see which way the rain is moving and then work out if you are in the firing line.

There are plenty of sites available now offering live rainfall radar simulations and they’re pretty accurate. I use’s V7 radar which is claimed to be accurate to 500m and it seldom lets me down, I do pay a yearly subscription because I use their site for other information (Jet stream predictions, etc).

Here’s their current output for 10.45 a.m. Tuesday 29th May, looks like the south-east is in the firing line again for some pretty heavy downpours.

So Tuesday looks like following a familiar pattern of late, lots of mist and low-lying cloud across central areas initially and a cool start. Before long though the sun will break through and burn this cloud cover away to give a brighter 2nd half to the day. Further west across Wales, Ireland and west-facing coasts, that cloud cover burns off quicker so you’ll see the sun first. Now it won’t be long before that sunshine is replaced by the possibility of rain, some of it heavy pushing up from the continent into south-east England, (see above) along the south coast into South Wales and The South West later. So from late morning onwards we can expect to see some rain for these areas accompanied by thunder and lightning. Tricky to state how far north these showers will come because of the vagaries of this type of process but at this stage they look to affect the south of the country only. A lovely day again for Scotland and Ireland alike but for the latter a risk of some thunder storms later in the day I think. Temperature-wise we should see low twenties across Ireland, Scotland, England and Wales once the cloud cover has burnt off. A predominantly north-easterly wind as we have had for a while now will be moderate to strong.

Wednesday sees the rain from Tuesday carrying overnight and continuing through the first parts of the day. Again tricky to say where we can expect to see this but areas south of a line from The Wash to The Severn Estuary are most likely to be affected. Again some of this rain will be heavy and localised. Cloudier on Wednesday along eastern coasts but no such worries for Ireland as another corker of a day comes you way, the same for Scotland. With a north-easterly wind, western coasts will see less cloud and a quicker burn off rate to reveal long spells of sunshine. Some of the cloud cover across the north-east will be thick enough for some rain later in the afternoon. Low twenties again for Scotland, Ireland and some western facing coastal areas vs. high teens if you’re under that cloud and rain base layer which will clear from the south-east through the 2nd part of the day. A subtle change in the light winds from north-east to southerly is expected.

Onto Thursday and Scotland’s run of lovely weather is predicted to come to a halt as that north-east rain pushes cloud cover and rain into Scotland in the wee hours. I’d say it’ll track more westerly across Scotland initially so not everyone seeing the rain. By the morning rush hour we may also see some rain into the south-east of England and south coast of Ireland and this will push northwards across Ireland, England and Wales through the morning and continue to track northwards through the day. So a more patchy picture on Thursday with some areas staying dry and seeing the sun but more in the way of cloud cover and rain around for sure. Ireland’s rain should clear north through the evening to leave a nice one to end the day. Temperature-wise it’ll be hot across England and that may mean a reccurence of some thundery downpours on Thursday with the combination of heat and a moisture-laden atmosphere. Across Wales, Ireland and Scotland expect high teens, possibly just nudging twenty degrees, so not bad all in all.  Winds are expected to be light and from the south / south-east.

Closing out the week on Friday we have a more unsettled picture with thicker cloud and rain pushing into the East Anglia and The Midlands and then tracking north and west through the 2nd part of the day. Some of this rain will be heavy and localised, accompanied by thunder and lightning. Ireland and Wales see the thicker cloud from the off accompanied by rainfall but not everywhere will see that rain. That thick cloud base pushes north through the morning to bring rain to North Wales, The North West and Scotland for the 2nd half of the day. So an unsettled day on Friday possibly clearing from The South East and Southern Ireland late in the evening to give a brief glimpse of sunshine. Northern England and The North East though may see some very heavy rain with thunder and lightning on Friday night. High teen temperatures are expected in most areas and again the winds will be very light and from the south predominantly.

The weekend is looking likely to be cloudy and unsettled with the re-emergence of that north-east wind, albeit light. So westerly areas may get the best of the weather on Saturday / Sunday and there’s likely to be rain around again on Saturday, predominantly affecting eastern coasts initially before moving inland and pushing into The Midlands, north of England and later Scotland. This rain will push thicker cloud ahead of it and this cloud will be a feature of Sunday as well, particularly on eastern coasts. Sunday looks drier, but still plenty of cloud cover because of that wind vectoring in off The North Sea. Temperature-wise I’d say high teens at best, a couple of degrees lower if you’re under the thicker part of that cloud base.

Weather Outlook

Really kind of strange weather lately because no one strong weather system is dominating. Instead we have a real mix of weak fronts and that makes forecasting especially hard I think, but here goes…

So next week looks like a weak high pressure system will remain in charge and so I think we will see a mainly easterly air flow and dry, settled conditions with little rain. I don’t think it will be stupidly hot, more pleasant like with high teens and low twenties the order of the day, probably more of the former than the latter. Around mid-week we see low pressure try and impose from the south so that means a possibility of thunder, lightning and rain but at this stage it is projected to miss us.  I think this could well change as we approach next weekend but at present dry and settled for all. If anything I expect the north and Scotland to hang onto the warmer temperatures next week and particularly at the end of the week.

Agronomic Notes

With the combination of high rainfall, temperature and humidity, I think we will see (or have already seen) quite a lot of turf maladies pop up.

Looking at the weather for my Midlands location over the last week you can clearly see the sudden increase in overnight temperatures on the 25th May and the high overnight relative humidity..

So the above combination will have given rise to some Microdochium nivale pressure for sure but with ideal growing conditions I don’t think this would have necessitated a fungicide application. (though some will have maybe wanted to use up any of their remaining Iprodione before the use up date in the first week of June)

You can see the high daily Growth Potential at the start of this week carrying on from last week…

So diseases like Microdochium will grow out as fast as they appear and once the sun is out and humidity drops markedly, so will the disease pressure.

Now I would also expect some of our more common summer diseases like Waitea Patch, Superficial Fairy Ring and possibly Rhizoctonia on shaded sites with poor airflow and high humidity (Stadia in particular) to also begin to show from now on as humidity and elevated soil moisture levels combined with high temperatures ramps up the pressure from these diseases.

Anthracnose Trigger Points

We know from past seasons that Anthracnose requires consistent days of 25°C for spore germination to take place. What it also needs through the same period is high humidity as well because the fungus isn’t a really strong grower outside the plant and needs plant leaf wetness / high levels of soil moisture to complete the initial phase of infection as a Biotroph. Thereafter it will sit in the plant taking some of its food reserves but not destroying plant cells. It appears to require a further trigger to become necrotrophic (killing plant cells) and studies suggest that this trigger could be when the plant goes under stress.

Now that can be heat stress and / or nutrient stress with clear research findings indicating that a plant maintained at a consistently low N status (I’d say below 3.25% leaf N tissue) more likely to be affected by the disease. Drought stress initiated by high temperature is another pre-cursor to the necrotrophic phase of this disease and of course when a plant is under drought stress it is unable to uptake sufficient nutrient from the soil (as the soil moisture level is too low to provide nutrients in soil solution. Work by Rutgers University has shown that maintaining nitrogen levels > 3.6% and potassium levels > 2.0% are key to reducing the severity of this disease, with nitrogen the stronger of the two influencing factors. In fact nitrogen was the strongest influencing factor and so the most important BMP when you are managing this disease, much more important than fungicide application. Anthracnose as a disease is one where putting the correct BMP’s in place can significantly reduce the impact of the disease regardless of pesticide use.

So far in early May we have had some days of consistently high temperature but looking at the weather station output for the same period it was accompanied by low humidity because it was warm, bright, sunny and windy. So I don’t think the early May weather was a signal for Anthracnose spore germination. I will analyse data from around the U.K and Ireland over the coming week to see if this past week has met the conditions for the biotrophic trigger for Colletotrichum cereale.

Even if the weather meets the required conditions for Anthracnose spore germination and initial fungal development, if we don’t then get periods of prolonged plant stress, we may not see the disease. Looking at the last 3-4 years, 2014 was the last year when we had a very hot August accompanied by high daily rainfall levels as well at times, in other words perfect for fungal development and plant stress and that’s when we last saw very aggressive Anthracnose foliar blight. Since then August has been a bit of a damp squib with persistent rainfall and cooler temperatures (I hope you haven’t booked your summer hols for this month :))

One last point before we leave this disease, genetic studies have shown two distinct genetic lineages for this disease, termed Clade A and Clade B, think of them as families within a population. Clade A is known to more frequently affect Poa annua and Clade B, Agrostis stolonifera. That’s why in the U.S, where they have both Clades present, you see references to this disease not only on Poa annua but also as a serious disease of Agrostis stolonifera. Over here we tend to see this disease mainly affecting Poa annua and so it is likely to be from a population belonging to Clade A. (10 distinct Anthracnose populations have been isolated worldwide on turfgrass and these populations either belong to Clade A or B)

Interesting eh ?

That’s it for this week…

All the best.

Mark Hunt


21st May

Hi All,

Time flies doesn’t it ?

We are already motoring through May in what is turning out to be generally a good greenkeeper / groundsman month all in all with some warm, dry weather and the odd frost thrown in for good measure.

This is nothing unusual because I always regard May as a bit of a yo-yo month weather-wise and one where night temperatures don’t really settle down till towards the end of the month.

Leaving early on Friday morning to catch the Eurostar (my first time), there was a good frost on the ground and temperatures were barely above freezing. What a nice way to travel that is by the way, very relaxing. Even a short delay on the way home due to a points problem wasn’t an issue as the Eurostar train conveniently came to a stop next to Hackney Marshes so I sat watching Reed Warblers, a Marsh Harrier, Buzzards and the like whilst time ticked by 🙂

Last week marked the 75th anniversary of The Dambuster raid and I was privileged to watch our only surviving Lancaster perform 4 passes over Eyebrook reservoir, one of the dams that the crews practiced on in the run up to the raid. Flying at 60ft at night, time and time again till they got it right.  The sound of those Merlin engines whether they be in a Lanc, Spitfire, Hurricane or Mustang give me goosebumps.

Talking of water, (tenuous link alert) May is also turning up to be a dry one for some with 17mm recorded here all month and 9 days now without a drop. I think that might be due to change in the next week or so, so rain isn’t far away for some.

Ok, so let’s look at what the weather has in store this week now I have my first coffee of the day in front of me and Vaughan William’s ‘Lark Ascending’ in the background.

General Weather Situation

So Monday starts the week with a thick band of rain already over Ireland and Scotland but unusually this one isn’t moving eastwards in fact it’ll clear from the east over both Scotland and Ireland with maybe East Leinster and Wexford missing the worst. South of this band of rain sees a lovely start to the week with sunshine already breaking through some hazy cloud cover after a cool night. So a mostly dry day for the U.K except for that band of stubborn-to-move rain over north west Scotland and the west of Ireland. It may not stay totally dry though because there’s a risk of showers with thunder and lightning forming over The Midlands and south of England later in the afternoon. Saying that as I proof read this blog I can see showers already appearing into Kent on the radar. Nice temperatures away from that rain over Ireland and Scotland which will see low teens, compared to low twenties for the central England and Wales. Winds will be light to moderate and from the north-east.

Onto Tuesday and with the arrival of moisture on Monday they’ll be more in the way of cloud cover present and this could well be thick enough for more showers inland and across the south-east of England later in the day. Ireland should see the last of the rain dissipate during the early hours leading to a much better day of sunshine, cloud and warmer temperatures. Scotland will have a thick cloud base over The Highlands, certainly thick enough for some rain but further south towards the borders you may see some sun and better temperatures. Towards the end of Tuesday marks the greatest risk of rain affecting the south-east of England. Again with warm temperatures and moisture there’s a risk of those showers being thundery in nature and accompanied by lightning. So 13-15°C where you have cloud cover and maybe 23°C across the south of England before those showers bubble up. Winds will remain from the north-east but will increase in intensity as we go through Tuesday and will remain moderate to blustery through the rest of the week.

A similar day on Wednesday with long, clear spells of unbroken sunshine but still with the risk of thundery showers across The South East and joined this time by a risk of showers across Connacht and Mayo later in the day. With a strong north-east wind the risk of cloud cover sitting along the eastern coastline of the U.K is significant and it is this cloud cover that could thicken to give showers later in the day. Much better temperatures across The Irish Sea with high teens and maybe a sneaky twenty thrown in there whilst England and Wales will sit between 20-22°C, Scotland 3-4°C cooler but still nice mind. Again a risk of rain / thundery showers across The South East.

Thursday again sees the risk of rain pushing into the south-east of England overnight bringing thicker cloud and cooler temperatures. This rain could potentially push up north and west into central regions, The Midlands and the north of England through the course of Thursday but it is tricky to say at this point. No such worries for Ireland and Scotland where the cloud cover will burn off to give a lovely day and temperatures into the low twenties, so Smithy, you owe me one 🙂 Through the afternoon we see that rain over central and southern areas continue to push north and west perhaps reaching the north-west of England. Ireland also may see some showers kick off down across south-west Munster later in the afternoon. Scotland looks to stay dry all day with plenty of sunshine and then cloud building later in the day.

Closing out not a bad week on Friday we see some potentially heavy rain in a tight precise band across The Midlands, Mid and North Wales and northern England. This band of rain (lighter now) may drift across The Irish Sea into Leinster and across to the west. So a good deal more cloud around for Central England with the risk of rain but here’s a big caveat.

This rain is from the continent and I’ve lost track of the number of times I’ve mentioned how unreliable it can be in terms of amounts and orientation.  North of this band of cloud and potential rain we see plenty of sunshine for the north of England, Scotland and Ireland from The Midlands north. Through the afternoon we will see more in the way of showers crop up for the south of Ireland, The Midlands and the north of England and these will slowly push westwards into the evening. The west and Scotland sees the better temperatures this time with low twenties for Ireland, Wales and Scotland but high teens for England with that cloud cover and threat of rain. Winds will remain strong to moderate north-easterly.

Ok so what’s the outlook for the May Bank Holiday (U.K only as Ireland’s is I think the week after).

Well I think we will follow a pretty similar pattern to the week really with the most significant threat of rain over the south / south east of England and extending up into The Midlands later on Sunday and through Monday as low pressure begins to edge that high away into Scandinavia. Saturday at this stage looks to be a good bit cooler than of late with more cloud cover for the south east, but temperatures will soon recover on Sunday. All of this rain risk originates from the continent pushing up from France so it’ll be pretty hit and miss I think. The forecasters tend to agree that the risk of rain and cloud cover seems to increase as we go through the Bank Holiday weekend for England. Further west and north of this is I think looking pretty damned good with long spells of sunshine and very warm temperatures. Plenty of cloud cover for eastern areas may make Wells and the Norfolk coast feel a bit nippier in that ever-present north easterly wind that we seem to have had for ages now.  Come Bank Holiday Monday I think we will see that threat of rain extend westwards towards Wales and The South West possibly.

Weather Outlook

So next week I think we will see the weather gradually deteriorate from the south as low pressure edges up bringing unsettled conditions into the north and west from mid-week onwards. These low pressure systems appear weak and slow-moving so they’re not associated with strong winds. I think on the whole we will see some rain, reasonable temperatures, high teens, maybe touching twenty degrees and more in the way of cloud cover through the week. If I was a betting man, I’d have Tuesday and Wednesday down as potentially the most unsettled days.

Agronomic Notes

New Insecticide for amenity usage ?

I hear some rumours that our industry is close to getting a new insecticide for Leatherjackets and Chafers on an emergency-use basis. It won’t be cheap for sure and it will probably not be labelled for use on all amenity turf areas but at least we may have an option in the worst case scenarios. This spring I’ve seen a good number of areas affected by Leatherjackets in particular with poorly-responding greens, tees and fairways a sure sign of their presence even though cultural work, climatic conditions and nutrition is in place to produce consistent grass growth.

A quick look back on how our year is tracking…

It never pays to forget where you came from and for me it doesn’t seem that long ago that the landscape looked bleak, wet and cold with precious little growth.

A while ago, I had some GDD data sent from a Northampton location comparing the previous years growth and rainfall data with the thought that 2018 most resembled 2016 in terms of these two parameters.

I decided to update this comparison as of yesterdays date to see how the comparison was shaping up and I think it is interesting…..

Growth Comparison – 2018 vs. 2017, 2016, 2013 – Location – Northampton

Looking at the data above we are still tracking 7 days behind last year from a cumulative Growth Potential perspective but when you consider that we were 28 days behind only a month ago, it gives you an indication of just how much growth we have had in the meantime.

May 2018 is actually tracking some 12% ahead of last year from a growth perspective so we are still in catch up mode and when you look at the forecast for the week ahead from a growth perspective, (below) it is likely that trend will continue…

That is of course if you have moisture available because it is likely in some areas that moisture will now be a limiting factor on grass growth on unirrigated areas of fairway, semi-rough and outfield. Last week’s Meteoturf predicted an E.T loss of roughly 25mm of moisture from the turf surface and this week’s prognosis is similar so that’s a lot of moisture to lose and not replace. That said plenty of areas are still showing the signs of the excessive rainfall of March so we won’t dwell on this too much at present. (Be careful what you wish for and all that….)

Rainfall Comparison – 2018 vs. 2017, 2016, 2013 – Location – Northampton

Have to say Rob’s contention back in April that 2018 most resembled 2016 is looking pretty accurate (I’ll give you that one Rob :)) when you look at the rainfall stats.

In fact on the graph above the years seem to separate into 2 very distinct data sets, 2018 and 2016 together and also 2013 and 2017 together.

2013, was of course the long, cold and dry winter / spring but to me it is interesting how closely they resemble each other. Both sets are within 10mm of rainfall of each other on 20th May, uncanny.

I wonder how long the 2018 and 2016 comparison will hold for because looking back to 2016 we had a warm and wet June and then a hot and dry July followed by a pretty good August as well. I wonder if 2018 will follow suit ?

Short and sweet this week.

All the best.

Mark Hunt


May 14th

Hi All,

At this time of year I think you see nature at its most vivid green with the air full of the scent of blossom (not great news for everyone I appreciate).

I had a friend over from Breckenridge, Colorado last week, he’s English, but settled over there and loves the mountain life and scenery in the U.S. He said to me that the first thing he noticed when he got out of the airport was the perfume-like smell in the air and the colour green. The depth of green is just so fresh and vibrant, it’s a pleasure to walk along the hedgerows and lanes lined with Keck (Cow Parsley to you), Pink and Red Campion’s and White Dead Nettles. I pick the flowers off the latter, squeeze their narrow tubes and suck the nectar out, it’s a lovely natural sugar rush whilst I’m plodding along 🙂

We got 8mm of un-forecasted rain on Saturday, came out of nowhere, all the models had Friday’s Irish rain dissipating as it came over The Irish Sea through the early hours of Saturday morning. About 4 p.m. my Netatmo weather station pinged me a notification whilst I was fishing to say more than 0.3mm of rain had fell over the last hour, a rogue shower I thought, not a bit of it, it rained all evening.

Just goes to show with everything available forecasters still can get it wrong and rainfall / snowfall are the most ikely culprits when they do.

Ok onto more mundane thoughts and that’s this weeks weather…

Now the good news is that last week we were due to have a low pressure system drop down later this week but that isn’t appearing now, so we are going to stay dry on the whole but we have a significant drop in temperature mid-week that will have you reaching for your extra layers for a day or two.

General Weather Situation

So Monday is pretty straight-forward, dry for everyone but initially we will see plenty of cloud cover over Ireland, western and eastern coasts. This will burn off during the morning to leave long spells of unbroken sunshine and pleasantly warm temperatures. Temperatures will be slightly cooler along the coasts, mid-teens being the order of the day here but it’ll rise to high teens and even touch twenty degrees in the south of England today. Winds will remain northerly orientated swinging round from north-west to north-east.

Tuesday sees a rain front push showers into Connacht during the morning and these along with thicker cloud will cross Ireland through the first part of the day. Elsewhere a dry start again with the sun soon breaking through to pick temperatures up. That rain across Ireland will move into the west / south-west of Scotland after lunch and push across country during the rest of the day. Further south we may see some showers spark off across northern and central regions later in the day but these will be hit and miss and almost un-forecastable. Cool under that thicker cloud and rain for Ireland and Scotland in the low teens but away from the effects of that rain front, expect high teens / low twenties and light north-easterly winds.

Wednesday sees the boot on the other foot with the north-east wind pushing cloud and Haar off The North Sea into The Midlands and southern England, whereas Scotland and Ireland will miss the effects of this and have much sunnier weather. That thick cloud cover and absence of sun will introduce a chill into the proceedings for central and northern England and parts of Wales keeping temperatures down in the low teens. Maybe West Wales will just miss the effects of this and see some sunshine over the lovely Pembrokeshire coastline. Mid-high teens for Ireland and Scotland in the sunshine and low teens for everyone stuck under the effects of the Haar. Late in the evening you may just see some sunshine here as the cloud cover breaks but that’ll drop temperatures even more to give a chilly night.

We keep that north-easterly / easterly wind through Thursday and that means eastern regions will remain on the chilly side but we will see more in the way of sunshine for central and southern regions on Thursday, though it’ll be hazy in nature. So western areas will benefit the most from being furthest from that easterly wind, borne on a colder than usual North Sea. The lower than normal sea temperature will be a feature of this year I think because whenever the wind swings north-easterly or easterly we will see a pronounced drop in temperatures. Currently the sea temperature off Norfolk is 9.5°C, which I think is a couple of degrees lower than normal. So Ireland, Scotland, Wales and the west of England will continue to benefit from the warmer temperatures with mid to high teens likely. Another chilly night for central areas.

Closing out the week on Friday we see a similar picture though with lighter easterly winds they’ll be less cloud cover and that’ll allow temperatures to rise a little over mid-week. Dry again for most of us with only a weak rain front likely to bring showers to Donegal and the north-west of Scotland through the afternoon. Similar temperatures to Thursday, mid to high teens depending on cloud cover.

With high pressure sat over us this coming weekend I think it’ll be another cracker with long spells of unbroken sunshine for Ireland, Scotland, Wales and England. Later on Sunday, a weak rain front from a nearby low pressure system may just try and push into north-west Connacht / Donegal but other than that, nothing to fret about. With less cloud cover and light winds I expect most places will see high teens to low twenties through the course of Saturday and maybe a little cooler for the west / north-west of Ireland on Sunday with that cloud cover.

Weather Outlook

I expect high pressure to stay in charge through the early part of next week so a continuation of the dry and settled conditions for most of us. I say most of us because that low pressure system that tried its best to push rain into north-west Ireland on Sunday will gradually nudge the high pressure away eastwards and that’ll mean an increasingly unsettled picture for western / north-western areas from Wednesday with rain possibly affecting southern and central areas towards the end of next week.

Agronomic Notes

Uptake windows and growth…

That rain on Saturday night coupled with warm day and night-time temperatures really moved growth on again and as we can see from the Meteoturf graphic above, that growth spike will continue unabated through today and tomorrow but come Wednesday we see a pronounced drop-off in Growth Potential with declining temperatures. I’ve documented the Meteoturf output below so you can see the type of information it is providing and hopefully assisting you when making management decisions.

So for me I’d apply anything isn’t critical to plant uptake (wetting agent for example) during the ‘downside’ of the Growth Potential chart and then products that require uptake (Nutrition, PGR’s, biostimulants, fungicides, selective herbicides and the like) on the upward part of the chart at the end of the week.

There’s been no research into this but I think products like PGR’s are very sensitive to temperature in terms of getting good uptake and therefore regulation.

The above uptake scenario is particularly relevant if you are maintaining turf with a high % of Poa annua present because currently the grass plant is in seedhead mode and the majority of carbohydrate reserves are being diverted away from the leaves, up the plant towards the seedhead.

It is therefore difficult to get the plant to respond to nutrition, PGR’s, iron products, etc. during this period. It is more of an issue when you are dealing with the annual biotype of Poa annua than the perennial one because the former produces a lot more seed heads and as it does so its basal leaves thicken and pale off making it very obvious to the eye within a darker stand of turf (ryegrass for example)

Geographical Comparisons – Growth and Rainfall – Scotland

Last week I asked for anyone who could share GDD / G.P / Rainfall data in Scotland, Wales and the north-west of England and I am indebted to Darren up at Machrihanish for answering the call. Really grateful as it allowed me to carry out a west vs. east comparison for Scotland with respect to growth stats and rainfall. Now many moons ago I use to work all of Scotland from Port Logan up to north of the Black Isle and so I am well-versed in the differences between locations in Scotland, so I thought I’d compare west vs. east using some of Darren’s data and a location on the coast in Fife.

I looked at Growth Potential and Rainfall as my comparison stats and I was amazed once I’d charted it out to see the similarities in terms of Growth Potential from two opposite sides of Scotland. They both got off to a slow start, with the west nudging head but from the middle of April, the east showed a faster growth curve to the point at the end of April when they share almost identical readings.

Now I know if I chose somewhere up on the north-east coast it would be a very different story but it is interesting nonetheless to see how closely the two Growth Potential curves follow each other.

The same cannot be said for rainfall though and again this comparison closely correlates with our west-east model in terms of rainfall totals, with westerly locations tending to come off worse.

Next week I should have a little more time so I’ll do Ireland and England, west-east and see how the cookie crumbles.

Enjoy the sun, wrap up well mid-week and don’t forget to use plenty of sun block come the weekend 🙂

All the best.

Mark Hunt

May 9th

Hi All,

Two days late this week with my blog due to the Bank Holiday here and work commitments.

Speaking of which wasn’t it a cracking Bank Holiday with some truly beautiful weather and very high temperatures capped I think with an early May Bank Holiday record measured at RAF Northolt at 28.7°C.

Got in some lovely walks including this one around Rutland with Eyebrook reservoir in the distance, scene of a lot of my fly fishing and one of the most-used reservoirs by the Lancaster’s of 617 Dambuster Squadron for practice in WWII. Along with the good weather came two new residents to my newly revamped garden. Last year I moved house and inherited a ‘modern style’ garden complete with decking, patios and mostly hard surface areas. A lot of work, 11 mt of vegetable topsoil later and a second mortgage spent with RHS Wisley and my local plant nursery, The Plant Man and it’s now naturalising well as a shade garden. Lot’s of log features, ferns and the like have encouraged a number of bird species to frequent (A Blackcap this week was a new visitor) and last week after making a number of 13cm x 13cm holes in gates, fences (my neighbours love me) and the like (earlier in the year), I was joined by 2 Hedgehogs that I feed nightly, cracking.

Ok enough of me, onto the weather and as you all probably know, our high pressure scenario is due to come to an end today / tomorrow with the arrival of a cool, Atlantic low.

The GIF below from Unisys Weather captures the scenario well.

Image courtesy of Unisys Weather

General Weather Situation

So today we see the beginning of the change to a more unsettled and cooler outlook with the influence of the above low pressure being felt first across Ireland and the west of the U.K during Wednesday. This process starts with a bad of rain due to push into the west of Ireland around now (7 a.m.) and move quickly eastwards across the country through the morning reaching the east of Ireland / west coastline of the U.K by early / mid-afternoon. Away from this impending rain front we have a lovely dry and settled start to the day after a cool night and very heavy dew. Cloud cover with build across The South West and Wales through the morning in advance of this rain front and this cloud will extend eastwards through the afternoon by which time we will see rain into the west of Scotland, Wales and the north-west of England. By late afternoon the west of Ireland will begin to clear that rain and the sun will break through but further east that rain front will be across western coasts and the middle of the country reaching eastern areas overnight into Thursday. Feeling a good bit cooler than of late with Ireland in the low teens and central and southern areas in the mid to high teens I think. Scotland with a bank of thicker cloud will be similar to Ireland down in the low teens after some lovely weather of late. Winds will be light to moderate westerly / north-westerly.

Onto Thursday (I must say I like 3-day blog weeks :)) and that rain is projected to clear the rest of the U.K overnight leaving behind a vestige of showers across north-west Scotland. They’ll continue to be some light rain showers across the western coastline of Scotland through the morning but these will eventually dissipate. Elsewhere after overnight rain we will see a bright start to the day in central and eastern regions and not a bad day with plenty of sunshine for the U.K and Ireland, mixed cloud cover and temperatures pushing up into the low to mid-teens in that sunshine. Winds will be moderate north westerlies, weakening as the day goes on to leave most areas with a calm, dry and sunny end to the day.

Closing out the shortened week on Friday we see the next chapter of that low pressure play out with a heavy band of rain moving into the west of Ireland in the early hours of Friday morning bringing heavy rain to Kerry I think. This front will be slow-moving and so the rainfall totals associated with it will be a good bit higher than the one on Wednesday.  East of that impending rain, the U.K will enjoy a dull, cloudy and dry start to Friday as cloud cover pushed in front of that low pressure tends to dominate the weather picture. That band of rain will stay over Ireland throughout Friday slowly moving eastwards and not clearing the west of Ireland till last afternoon / early evening by which time it’ll be approaching The South West.

So you can probably guess that Saturday’s outlook for the U.K is unsettled with that band of rain crossing The Irish Sea late on Friday night to give heavy bursts of rain overnight for Wales before clearing east into The Midlands and north of England through Saturday morning. At this stage it looks like the south-east of England will miss the worst of it but I think we will see heavier rain for North Wales, north-west England and the west of Scotland through the first part of Saturday. That rain looks to concentrate across Central Scotland through Saturday to give some pretty hefty daily rainfall totals I’m afraid. By Saturday afternoon we will see a band of showers crossing Ireland and a clearing picture across the southern half of the U.K with some showers later for The South West and Wales. Cooler in that rain with temperatures in the low double figures across Ireland, Wales and Scotland, perhaps a degree or two higher for Central England. Winds will be westerly veering south-westerly and then northerly for Sunday which will drop temperatures a degree or two. Sunday looks the better day of the weekend, still with the threat of rain across the south-east of Munster during the morning but elsewhere plenty of sunshine and some hazy cloud cover. That change in wind direction will usher in some thicker cloud for north-east / eastern coasts on Sunday with some of that cloud thick enough to give rain along its leading edge. So sunnier and brighter the further west you go on Sunday with similar temperatures to Saturday.

Weather Outlook

Actually next week doesn’t look too bad I’d say with low pressure influencing our weather early in the week bringing a sunshine and showers-type scenario to the U.K and Ireland with more threat of rain I think across Ireland, the north-west of England and Scotland on Tuesday / Wednesday a.m. With a westerly airflow in situ we will pick up some milder air and a return to more normal temperatures for this time of year, mid to high teens I think will be the order of the day. Towards the end of the week there’s a suggestion of a new low pressure coming in which will bring more rain to Ireland and the southern half of the U.K but that’s a good way away at present so let’s hope it doesn’t happen.

Agronomic Notes

As this is my first blog of May, we have the opportunity to look back on April and the year to date.

April 2018 GDD – Thame Location

The GDD total for April came in at 99.5 which represents not a bad growing month however as more detailed analysis below will show it was a topsy-turvy one from this perspective.

In isolation April provided nearly double the amount of growth we had in January, February and March combined and 5 times the growth of March alone, illustrating just what a crappy month March 2018 was.

Cumulatively for the year, 2018 is unsurprisingly classified as an under-performer, GDD-wise, with a running total till the end of April of 156.5. It does indeed share a good deal of similarities with the other SSW-affected years of 2010 (159.5), 2013 (119) and 2016 (137.5) in having a low spring total.

In comparison with last year, 2018 y.t.d has recorded nearly 50% less GDD for the first four months.

GDD Comparison – April 2018 – U.K Locations

Firstly, a quick word of thanks for the growing number of people sending me in data on a monthly basis, many thanks, still short though for Wales, the north-west, north-east and Scotland though.

So analysis of the U.K locations shows a very variable GDD picture with our east of Scotland location running at nearly half the GDD of our Devon location !

Fortunately for Fife the same can be said for the rainfall total which goes some way to compensate I think…:)

In general The Midlands comes out favourably with higher GDD totals than most locations further south which must be a first I reckon. Rainfall-wise a good deal of similarity with 75mm looking to be about average for the month.

You can download this chart here ;

GDD Comparison – April 2018 – Irish Locations

A much cooler April for Ireland compared to the U.K sites and I’d say the western side of Ireland looks milder to me than the east or south.

That said there was a really significant flip side to this coin when it came to rainfall and so I’m sure the lads in Kerry, Mayo, Sligo, Clare and the like will be tutting and rolling their eyes to the sky at my stats above showing rainfall and E.T loss for the Thame location and wishing it was them. I had to create a different graph for the Ireland locations simply to fit on the rainfall totals for Valentia, Cork and Limerick, with the latter exceeding 10 inches of rainfall during April.

Of that total, nearly half of it came on the days of the 6th and 16th of April, with > 40mm of rainfall in a day measured at a number of locations across Ireland on the same dates. So it’s no wonder it was milder as well because the low pressure associated with that rainfall will have pulled in milder air, little compensation I know so I’ll shut up about it now.

You can download the above chart here ;

April 2018 in more detail…

Ok I cheated a bit here because I’ve added on the first 8 days in May as well to illustrate the growth peaks and troughs we have experienced over the last 5 weeks…

Again emphasising the worth of tracking growth patterns using GDD / G.P we can see the two significant peaks in growth that we have experienced during April and the early part of May.

Now in other years we would be bemoaning the growth peaks for too much grass, clipping yield, etc but after the memories of March 2018, I didn’t hear one peep of protest 🙂

Those 5 days of growth during mid-April transformed many a lagging-behind turf surface, be that a golf green, winter tee, cricket outfield, square and football pitch alike and brought a smile to many a strained face as an aside (including my own it has to be said 🙂 )

Following that though we dropped off a cliff with those cold, dull days of late April representing minimal growth and reflecting poor uptake conditions as well. Plenty of sites marched right up to Poa seedhead development at this point and although seedheads weren’t visible on the turf surface, the Poa plant had already flicked a switch away from leaf / root growth towards seedhead development. So associated with this spell of cold weather also came a Poa plant going off colour and with a reduced growth rate to boot that wasn’t keen on responding to nutrient, iron or PGR inputs.

Thankfully we turned a corner when we turned the page of the calendar over to May as the graph above illustrates with a welcome rise in temperatures and grass growth although in central and southern England, the temperature got high enough to put Poa annua under stress.

Looking at the first 8 days of May, here’s how the rainfall and E.T levels panned out at the same location…

So the combined E.T loss was 25.9mm with 7.6mm of rain to compensate but that still left this location -18.3mm, which is significant over such a short period.

Now a lot of you will be reading this and remarking how this chap can’t seriously be moaning about things drying out when the site has only just become workable and of course I’m not.

I’m just making the point that at some locations, the grass plant went under pretty severe stress over the last week or so and in the case of Poa annua this will have driven the seedhead process forward significantly.

I got asked recently what drives the seedhead process for Poa annua and if the factors differ between the Poa annua annual and perennial biotypes ?

Honestly that’s too good a question for me (another way of saying I’m not clever enough to answer it in I suppose 😛 ) but I would say this. Elevated stress periods,  particularly high temperature and the reciprocating lack of moisture will cause nitrogen uptake to drop in the Poa annua plant and this I believe is a major contributory factor to seedhead development and expression. Run your plants too low on N and expect to see a continued seedhead flush. Now I’m not saying lash on N, you should know by now that isn’t my bag, it’s a question of balance, (isn’t it always) keeping the plant healthy and not over / under-fed.

O.K that’s it for this week, hopefully we will be back to Monday as the blog day next week and in the meantime I wish you all the best for the rest of this week.

Mark Hunt