Hi All,

I am on my hols for the next fortnight down in The beautiful Cevenne in France where I can report the weather is very nice indeed. I’m sitting typing this blog and there are 9 Griffin Vultures circling above me, strange I didn’t think ICL worked this far south 🙂

Here like us they have had their heatwave and then their cold, very wet period and now it is pleasant. So this week’s blog will be mini one focussing on a general weather synopsis and most importantly a peak into next week to see what we have in store and if there’s any change in the position of the jet stream. It’s a good job I am on my hols because it looks like Meteoblue are also en vacances judging by their output 🙂

DGzDZtEWsAAGqa9Last week I presented at The Grass Court Seminar held at A.E.L.T.C, Wimbledon and I’d like to say thanks to Neil, Grant, my fellow speakers and of course the audience for listening to my chat. It was a great networking event and very interesting for me to listen to how the game of tennis has changed, how that effects the wear patterns on the grass and what the future holds. During the run up to this years championships and courtesy of  a peak pattern in the jet stream that pushed heat up from Spain, the temperature on the baseline on Centre Court exceeded 40°C on a number of days. Now that’s beyond the comfort zone of most cool season grasses including Lolium perene. I’ll talk a bit about this later but first a quick coffee and Croissant 🙂

General Weather Situation – Summary

As you can see from the animated GIF courtesy of Paul in our office, we have an active low pressure system in place this week and that’ll bring more rain for most areas however I have some good news as from Sunday it looks like high pressure will begin to exert its influence and that means warmer and crucially drier weather for us all for next week I think (sticking my neck out a bit)

So putting some detail into this forecast from a rainfall perspective ;

On Monday we have the first of those wet and windy shower bands moving north east across the U.K stretching from the south west of England all the way up to the north east. Scotland is sitting under some heavy rain today which will slowly move north and east so this part of Scotland in particular is set for a very wet Monday indeed. The same pattern of rain is present over Ireland with a band stretching north east from Kerry all the way up to Derry. Mid to late morning it’s likely The Midlands will pick up some of this rain as well but south and east of this I think you’ll be fine today. Overnight and we’ll see more rain pushing in across Ireland, the north west of England and Scotland on Tuesday, not as heavy this time and this will potentially push eastwards across The Midlands into south and eastern England early doors Tuesday. Once this rain clears through the morning, it looks drier. The wettest band of weather this week will push in over the second half of Wednesday across Ireland, Wales and then overnight into Thursday for the rest of the U.K giving a wet Thursday morning for many. Strangely a lot of the rain will fall overnight this week. We finish the week off with a showery picture on Friday with blustery showers pushing in across Ireland and quickly whisking over The Irish Sea to give an unsettled picture for both Friday and Saturday. The good news is from Sunday we will see that high pressure edge in and bring a settled and drier theme to most of the U.K and Ireland so happy days and long overdue. Wind-wise it’ll be a blustery week with strong to moderate south westerly winds turning more westerly as we approach the end of the week. Temperature-wise we will fluctuate from mid-high teens during the rain events to just touching twenty degrees during the drier interludes.

Weather Outlook

Next week looks fine and settled for most of the U.K as the jet stream takes a hike up north and allows warmer and settled weather to predominate, We will see a northerly low just glance the top of the U.K during the early part of the week and that’ll mean some unsettled weather still for Scotland on Monday and Tuesday before you join the dry and settled picture for the rest of the week.

Agronomic Notes


A lot of clubs are doing renovation in August and this weeks (and last weeks) weather will make that a tricky process in terms of core harvesting and getting that sand dried out enough to fill in the core holes (or graden slits depending on your preference). Thankfully though the sunshine and showers and reasonable temperatures will mean a very good outlook for growth with near optimum conditions over the coming week for recovery.


That good growth and moist plant leaf will unfortunately mean disease pressure remains high and that’ll particularly apply to foliar pathogens like Microdochium nivale, Red Thread, Dollar Spot and Leaf Spot.

High Humidity = High Disease Pressure

From the end of July to the present date and including the coming week we will have had 4 weeks of high relative humidity and a moist plant leaf and that has driven some of the worst Microdochium activity I have seen for this time of year. Disease pressure from Dollar Spot has also been particularly aggressive on some sites. Dollar Spot is significantly influenced by plant leaf wetness and this is why we’ve seen activity over the last 3-4 weeks.

As a disease it also prefers to grow in acidic conditions in terms of plant leaf surface pH so if you’re planning on applying sulphate of iron and sulphate of ammonia to this disease, think again because you’ll be playing right into its sweet spot. Once we get through the weekend I expect disease pressure to drop back significantly as drier conditions prevail.

High air temperatures are a great PGR and they’re free…..

On another subject and prior to going into another spell of warm, settled weather (though hopefully not as hot as late June’s) it’s worth taking the time to consider our use of PGR’s during the summer heat. We know some grass species like Poa annua are affected more by Trinexapac-ethyl than bentgrass sp. so if you’re managing a mixed Poa / Bent stand and applying TE, the effect will not be uniform it will be proportionate to the species content you have and this may vary from green to green on the course.

Bearing in mind that during some parts of the summer we hit temperatures > 26°C for sustained periods of time (I put this figure specifically because above it Poa annua doesn’t really like to grow much and goes under heat stress)  it is quite likely that the growth rate of Poa annua suffered because of high temperatures. In addition we then applied a PGR to our grass stand to hold back growth, effectively a double whammy on Poa annua already checked by high temperatures. So I got quite a lot of reports of Poa looking yellow and sickly during June and July and this is why I think, the collective result of high temperatures and TE applications. Now you could argue that if you were also overseeding bentgrass during this period then you would be tipping the balance in favour of this grass vs. Poa so the strategy may have an upside as well. (particularly if it is creeping bentgrass)

The same rationale would apply for those maintaining a mixed stand of Lolium perenne and Poa annua during the summer months (though I appreciate many of you do summer renovations on sportsfields), the high temperatures and a PGR application would hold back the Poa annua and because TE affects Lolium less, it would have a competitive advantage in terms of growth and establishment.

One last point here and that concerns the rebound effect when TE breaks down in the grass plant and the plant ‘rebounds’ from its suppressive effect. During this summer’s high temperatures we probably only got 10-12 days of suppression before this occurred on fine turf so if you were applying at longer intervals than this it is quite likely you saw a surge in clipping yield even though you had applied a PGR two weeks prior to this. So I guess what I am saying is if you’re committed to using PGR’s, keep your application intervals tight. I know you read those tweets concerning high rate applications on fine turf but in essence they are for me no more than bragging rights with little scientific basis.

The key to TE is frequency of application and not rate and there’s good, unbiased research to support this statement.

Ok that’s it for me, time to get the factor 30 and walking boots on, turn the phone off and forget low pressure systems for a few days. All the best to you all.

Mark Hunt