May 18th

Hi All,

One of my now ‘normal’ daily rituals of Corona virus is to take my temperature in the morning, at lunch and in the evening. My body temperature invariably sits below 36 °C whereas my significant other is another degree higher on the same thermometer.

This has led to a growing number of negative comments / assertions to me not being ‘normal’. It also appears to provide a clear explanation as to my preference to have the central heating turned down to 17 °C during the winter  because I am ‘genetically conditioned’ to tolerate lower temperatures due to my preset body temperature vs. other people. I blame being brought up in  a house where I was the only full-time occupant of an upstairs extension and it had no effective central heating. Our pet cat at the time used to ask to go out because it was warmer sitting on the AGA chimney outside than indoors in my bedroom. It seems funny to me that the effects of this ‘conditioning’ have only come to light now and had I not started taking my temperature regularly because of this pandemic, would have been lost on me.

Before I move onto the weather and all things grass, a quick update on the Hedgehog front. Last week I nipped along to the Leicester Wildlife Centre and duly undertook a socially-distanced pick up of ‘Parky’. It was quite a clandestine experience, I received a text explaining where I was to go and there I’d find a Hedgehog in a box and I was to transfer to my box and then depart wearing of course the obligatory face mask and gloves.

When I dropped ‘Parky’ off just after Christmas he weighed barely 200 gms and wasn’t expected to survive.  Now he was much fatter, healthier and ready to return to the wild. I took him home, put him in a pre-prepared Hedgehog house, closed off the entrance until nightfall and then let him go, he was scratching to get out. He duly walked round the garden, sniffed everything and disappeared into the park from whence he had appeared last Christmas. Happily he is back every evening and seems to be accompanying ‘Shifty’, another visiting Hedgehog. I think they’re from the same family because they tolerate each other. Great to see but unfortunately I know the Badger is still visiting the park so in time he may not lost 🙁

OK, onto the weather and let’s see if the Daily Express headlines of a ‘heat plume for weeks’ bares any semblance of the truth (unlikely eh)

General Weather Situation

If you look back at last week’s blog, you’ll see that the GFS projection for Monday 18th May vs. the actual shown above are practically identical. So we have high pressure in charge over the south of the country and low pressure across the north. The latter brought some very welcome rain to Scotland over the weekend with more to follow this week for Scotland and the north of England.

So for Monday we have this north-south divide with bands of rain currently sitting across Connacht, the west of Scotland and The Pennines. This rain will move east / north-east through the course of the morning to push rain across to eastern counties of Scotland and The North East of England. Further south the sun is out and temperatures are on the up so we look to have a mix of cooler and unsettled conditions with rain across the north west / north of Ireland, the west of Scotland and maybe later some of that rain popping up across North Wales, The Lakes and north east of England. Further south we look to have a dry, bright day with perhaps more in the way of cloud later for The Midlands. Under that rain and cloud expect to see temperatures around the mid-teens but across The Midlands and south of England we could see temperatures popping up into the low twenties. Ireland also sees a south-north divide with cooler and wetter conditions across the north west and northern counties with some of that rain pushing into Leinster later in the day. Winds will be strong to moderate and from the west.

Overnight into Tuesday and that rain continues to affect the north west of Ireland and England and also the west of Scotland from early doors. On Tuesday is looks like most of the rain is for the west of Scotland and central areas with little making it across to the east. They’ll be some showers around again across Connacht and Leinster but mostly dry for Ireland with the sunniest conditions across the south. The same north-south divide again for the U.K with rain, cloud and cooler conditions for the north and Scotland and hotter, drier conditions for the south with temperatures up into the low twenties again on Tuesday. No repeat of last weeks cold starts and night frosts this week with night temperatures staying up in double figures.

Wednesday sees the low pressure re-orientate further south and push a band of rain in from The Atlantic. At this stage however it isn’t projected to make landfall across the west of Ireland until the close of the day so Ireland, England, Wales and Scotland look to enjoy a mainly dry, sunny day on Wednesday with the odd shower across the west of Scotland. That change in the orientation of the low pressure will tilt the winds from westerly to south westerly and this will usher up much warmer air across the south of England pushing temperatures up into the mid-twenties. Certainly the hottest day of the week. Ireland and Scotland will be just into the twenties I should think.

Thursday sees that band of rain move vertically across Ireland overnight and by dawn it’ll be across The Midlands of Ireland and eastern counties before departing off to The Irish Sea. Now this ones a tricky one because the rise in humidity may trigger some heavy snap showers across Wales, The Midlands and east of England during Thursday afternoon. Quite where and how much remains to be seen. The rest of the rain looks to head across to the west of Scotland again for Thursday morning and then move eastwards across most of the country during the day. So potentially wet across The Midlands and East Anglia during the 2nd half of the day but it’s going to be a click the radar jobbie to understand if its coming your way. I certainly hope so here in Market Harborough because South Leicestershire / Northamptonshire is as dry as a bone. Warm again across the south of England / Central England with temperatures in the low twenties, 4-5°c cooler across Ireland and Scotland under that cloud cover, but still pleasant mind.

Thursday night / Friday morning sees The Atlantic low puff out its chest and push some closely-packed isobars indicating strong south westerly winds for Ireland overnight. This increasing wind strength will be accompanied by rain, some of it heavy affecting Ireland through the early hours of Friday morning. By the increasingly busy, morning rush hour we will see rain and strong winds into western coasts of the U.K, whilst Ireland takes a breather between the rain fronts. This rain across the western side of the U.K will unfortunately push north and west across Wales, but missing The Midlands and south of England and instead affecting The North West and west of Scotland. Some of the rain will be heavy. So showers across Ireland after the earlier rain, wet / very wet for Scotland and dry but cooler for England and Wales with more in the way of cloud and the odd shower making it inland.

The outlook for the weekend looks cooler and more unsettled on Saturday but again the bulk of any rain will be further north and west across Ireland and the U.K. By Sunday high pressure from the continent begins to push up and that’ll put an end to any hopes of rain. More in the way of cloud across the weekend and temperatures staying down to high teens across Wales and England, a little lower for Ireland and Scotland with that thicker cloud and higher likelihood of rain.

Weather Outlook

So the rain gods have answered Scotland but for England we are dry, dry, dry. Spring crops sown late like maize isn’t even through the ground where I am because of the lack of rainfall.

So does next week bring any likelihood of a change ?

Well Golly Gosh it does, but before we get excited, the signal is 10-days away currently, it could easily change so I’d be cautious at this stage.

The projected thematic for next week is for a trough pattern to form in the jet stream (now I see what you’re on about Rob !) by mid-week and we know what that means. Slow-moving and more southerly-orientated rainfall. So the early part of next week looks to be a continuation of this week really, that of pleasantly warm conditions for the south of England and cooler / fresher across the west and north with stronger winds. During Tuesday we will see that change take place (if indeed it stays on track) with low pressure pushing rain into Ireland late on Tuesday and following that up by cooler, cloudier and windier conditions pushing into the U.K with the odd shower on Wednesday. With a trough pattern in situ, don’t expect the rain to move quickly and so Ireland gets its share first before rain pushes across The Irish Sea into all of the U.K by Thursday lasting through to the weekend.  That trough pattern will still push rain and cooler conditions across the weekend into the early part of the week after next but it will be slowly pushed westwards by increasing pressure over the continent. Well a lot can and will change from then to now, let us focus on the potential positive of a change in the rainfall stakes albeit still 10 days away and hope it stays on track.

Agronomic Notes

Some of the clubs across the U.K  ‘welcomed’ back golfers last week, I hope they were all appreciative of the efforts of the greenkeeping staff, many of whom’s numbers were depleted by furlough. I managed to fly fish over the weekend and I was so appreciative of the opportunity just to get out there and do so. I hope golfers are of the same mentality ?

How dry are we ?

April saw many areas have a very dry month with strong sunshine and high evapotranspiration (E.T).

In The Midlands it also saw our last appreciable rain at the end of the month. We all know we started the year extremely wet, particularly during February and the first half of March but since then we have been extremely dry. I have charted the rainfall and E.T from the start of March just to see where we are at from a soil moisture deficit.(Ta Rob)

As you can see we have been running some consistently high E.T days (> 3.5mm loss per day) from the beginning of April and continuing through May. Our rainfall pattern from the winter changed around the 19th of March, that’s when we saw an end to consistent rainfall.

We have had one episode of heavy rain at the end of April and that’s been it. So from the beginning of March to yesterday we are running a soil moisture deficit of 122.5mm, that’s just under 5″ in old money.

This week looks like continuing that trend with a projected E.T loss for this location of 27 mm over the next 7 days from Meteoblue, that averages out at just under 4 mm per day.

In reality, we know the first half of the week is warmer than the second so I’d expect the daily E.T to hit 5 mm on Wednesday with the combination of warm, bright conditions and strong to moderate wind.

Now we have talked about irrigating and E.T before but it’s worth revisiting this topic in my humble opinion. If we lose 5 mm of moisture in a day it doesn’t mean you’ll need to irrigate and apply 5 mm to replace it. The reality is that the E.T calculation over-estimates the E.T loss from grass. In practice most end-users who irrigate to their daily E.T find they can keep a healthy turf within their chosen soil moisture parameters with 50-60% of E.T replacement by irrigation.  That doesn’t account for ‘hot spots’ like bunker splash-affected areas, ridges on greens and / or high spots. These often need supplementary irrigation in the form of hand-watering to equalise the moisture deficit in localised areas.

What the discussion above does highlight though is that unless you have an understanding of the E.T loss for your site and of course how much mm of water you are applying for a given run time, you are wishing in the wind (I think that’s the term) when you allocate an irrigation requirement for your surfaces.

Now of course life isn’t that straight-forward as there are a myriad of additional factors that will affect irrigation requirement, not least root development, surface organic matter content and grass species to name but a few. In practice the only way of truly understanding how much you need to irrigate for your turf at your facility is to possess a soil moisture meter, an on site weather station (to measure the type of stats I’ve presented above) and of course a reasonably functional irrigation system (not always a given in my experience !)

Disease Pressure

As temperatures begin to climb into the mid-twenties in some areas of the U.K and Ireland, my thoughts automatically (because I am sad like) turn towards the trigger for Anthracnose which according to Rutgers University (and my own experience) requires continual day time temperatures for a set period of time above 25°C, accompanied by humidity (to facilitate fungal growth).

Now for this disease it isn’t a simple open and shut case when we talk about these triggers because in recent years we have had the triggers but sometimes not the accompanying disease pressure further down the line. Some of this of course may be down to better agronomics because like most diseases keeping the plant healthy will dramatically reduce the risk of Anthracnose incidence. The work at Rutgers identified low plant nitrogen levels as being critical to the incidence of this disease. So it follows that if you are managing plant stress and keeping the plant adequately fed from a nutritional basis, you will automatically be employing most of the preventative measures for Anthracnose.

I think there is possibly another piece of the puzzle though with this fungus because it is slow-growing and therefore more sensitive to climatic conditions. Like most turf diseases, plant leaf moisture is the driver and so if we don’t have the combination of high temperature (for spore germination) followed by high humidity (for fungal mycelial growth), it may not develop. This week could see our first trigger for Anthracnose development across the south of England. Time and more importantly, weather conditions will tell if we see a reciprocal spike in turf symptoms later down the line.

Keeping the plant ticking over during daily high E.T periods…

Like most things in life, managing the grass plant during periods of high daily E.T is a balancing act.

Obviously managing soil moisture is key to not only providing the plant with sufficient water to maintain its water status but also to keep soil nutrients in solution. I know its common sense but if the soil rootzone is dry with a low moisture status, it will be unable to uptake nutrients from the soil. Now most of our turf nutrition at this time of year is of course foliar or part-foliar depending on water volumes and subsequent irrigation but it doesn’t mean that you can bypass the effects of low soil moisture by inputting nutrient through the leaf. During periods of high E.T, the grass plant will undergo various physiological changes to limit water loss to the environment, one of these changes is of course closing the stomatal pores, a process which ultimately limits nutrient movement from the foliage into the plant so logically foliar nutrition is less effective during periods of high E.T. The use of biostimulants to help the plant manage stress is I’d argue just as important during these periods of weather as maintaining adequate but not excessive plant N tissue levels. There is a growing body of evidence that bioactive biostimulants help the plant to manage stress, the key will be to understanding which parts / constituents of a biostimulant do this the most effectively.

That my friends is a huge topic and one I’d not even going to start covering this morning !

OK, that’s me for another week, enjoy the sun and rain depending on where you are and let’s see that if by this time next week, that trough signal is still on track 🙂

All the best.

Mark Hunt