June 26th

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Hi All,

This time last week we were sweltering (well some of us were) in high 20’s,JuneTrough low 30’s heat and we went on to record the hottest June day for 41 years measured at 34.5°C at Heathrow I think.

The projections back then for this week were a move from a hot peak in the jet stream to a cool and crucially wet trough and that’s where we are going for sure…Already we can see the first pulse of heavy rain just moving into the west of Ireland on rain radar. This trough will feature a succession of slow-moving, low pressure systems pushing in this week so that means rain, some of it heavy for the U.K and Ireland. So put away that factor 30 and get out your Nikwax and waterproofs because you’ll need them this week !

General Weather Situation

So Monday sees that first pulse of heavy rain pushing into Ireland and heading north east so the heaviest rain will affect Connacht, Donegal, the north of Ireland before pushing across country slowly until just the south east of Ireland escapes the rain till dusk. Remember how I said fronts would be slow-moving in this weather system well Monday is likely to be the only dry day for the U.K because the rain stays confined to Ireland giving a warm and pleasant day for much of England, Wales and Scotland with light to moderate, north westerly winds and temperatures in high teens, low twenties.

Overnight into Tuesday and that rain has pushed into Scotland bringing heavy rain to the south west of Scotland in particular. As we approach morning rush hour that rain will have moved south into northern England and a seperate front will push into The South West and along the south coast. By mid-morning Ireland looks to be clear from the last of the rain, meanwhile over The Irish Sea and it’s pushing up from The South West into South Wales and The Midlands joining up with the northern front of rain which is pushing southwards across the U.K. By early afternoon most of the U.K is covered by rain with some heavy pulses expected across the south coast, Bristol area, really following the M5 up into The Midlands I’d wager. So a pretty manky day when all is said and done but of course we need this rain desperately to top up irrigation lakes, river systems and the like, such has been the deficit this year. So mid to high teens away from the rain in Ireland where you’ll have a pleasant day and the same for areas across the U.K until the rain arrives when it’ll drop to mid-teens. Some areas may not see this rain till close of play Tuesday, but see it you will.

Moving onto Wednesday and that slow-moving low pressure revolves around on its axis to bring more rain and thick cloud across the U.K for Wednesday with heavy pulses expected across The Midlands, the east and north east coast of England. Ireland may see some rain across the north and west but this will clear through the morning to give a largely dry day before showers push in from the south west later in the day. That rain looks to stay more central and east-orientated through the day clearing Wales and the west by late morning to leave thicker cloud and showers remaining. By late afternoon / dusk that band of heavy rain will have moved up the north east coast into Scotland and it’ll push north during the evening but always more east in its orientation. So another pretty wet day for some areas of the U.K and temperatures barely making it into the mid-teens under that rain, maybe a degree or two higher for Ireland and the west.

By Thursday morning that pulse of heavy rain is affecting an area from The Pennines up to Scotland so here you can expect a very wet start to the day. The low pressure system begins to complete its third anti-clockwise rotation and in so doing moves the rain across Scotland and down into the north of Ireland by the morning rush hour.  Meanwhile more rain fronts will push in from the west across Ireland and into The South West and Wales through the morning, tracking eastwards. By the afternoon the top half of Ireland, drawing a line from the south of Leinster up to the north of Connacht, is affected by heavy rain as will be the majority of Scotland aside from the east. Through the afternoon that rain sinks south across the east of Ireland with the west missing the worst of it. It’ll also affect the west coast of England and Wales so central and eastern areas will remain reasonably dry in the main. A south westerly wind takes over from Thursday as the low spins on its axis and that’ll end up pushing rain into central areas on Friday. Mid to high teens again temperature-wise.

So we close out what will have been for some a very wet week bearing in mind Saturday marks the first day of July with more rain for Friday. So Friday looks to be rain for almost all areas as the low pressure begins its fourth rotation across the U.K. I mention this because normally low pressure systems move across the U.K and Ireland in 12-18 hours completing perhaps one rotation before moving off into The North Sea. When we have a trough in the jet stream it fixes weather systems in place and so they can go through multiple rotations leading to heavy, localised rainfall. So Friday sees thick cloud and heavy showers for most of the U.K and Ireland, with maybe the west coast of Ireland seeing less of the rain. Through the morning that rain moves eastwards across Scotland, Wales and England so all places are likely to see some rain pushed along on light to moderate westerly winds. As that rain moves east it clears Ireland and you might even see some sunshine there down in south Munster for Friday evening. Similar temperatures to Thursday with mid to high teens the order of the day.

The weekend outlook looks unsettled but maybe Saturday will be largely dry before strengthening north westerly winds push more rain fronts in from The Atlantic for Sunday for all parts of the U.K and Ireland.

Weather Outlook

So does the trough pattern continue or do we see a return to summer for the w/c 3rd July ?

Well at this stage it looks like the former, same, but different in that the low pressure systems will be the more usual Atlantic, rather than southerly-orientated ones. So I think we will start off next week with a pleasant Monday, warmer even as we get a brief hint of summer before the next low pressure system arrives to bring rain to Ireland later that day, sweeping north and east across into the U.K for Tuesday morning pushed along by some strong winds to boot. Thereafter we will be sunshine and showers for all but I think we have some heavier rain for the south west of Ireland / U.K waiting in the wings on Thursday to spin up for the end of the week / weekend.

Agronomic Notes

Last week was definitely an “Any ideas what this is” week with lots of turf maladies coming out of the woodwork.

If you took your surfaces through the heat and high E.T largely unscathed then you can give yourself a pat on the back for all the hand-watering, syringing and well-timed irrigation you carried out.

Deep aeration pays dividends during dry, hot periods of weather…

It’s not just a case of work carrfied out now either because organic matter management and decompaction using the vertidrain / Air2G2 for example really bears fruit during periods like these with better rooting in decompacted, higher oxygen content soils.

Below are a couple of nice pics sent in from sunny Kent (Thanks Toddy) showing quite clearly the line between winter vertidraining and non-vertidraining in terms of drought stress.

vertidrain2 vertidrain

A lot of people associate use of the vertidrain as a winter operation but I don’t agree because decompacting and more specifically, providing gaseous exchange and water movement during and prior to heat stress can be really advantageous as well as initiating new root development. I remember back in 2014 visiting a course during August with very bad Anthracnose and all bar 2 greens were heavily infected / affected by this disease. The two greens which were relatively unscathed were those that had been vertidrained during July. Makes you think doesn’t it….?

The same is true for organic matter control…

The temperature and humidity stats shown below are from a Central London location and show the run of high temperature days that we experienced and together with very high rates of evapotranspiration, they really pile the pressure on the grass plant, particularly when you take into account how (on greens) we remove most of the leaves required for photosynthesis and respiration and then expect the grass plant to cope with the situation !

Junestats

If you have a compact surface fibre layer where the roots are bridged (growing horizontally, rather than downward into the rootzone) then the kind of weather we have had recently really piles the pressure on the poor old grass plant.

bridged

Organic matter heats up much more quickly than soil and so areas with high surface organic matter go under stress much more quickly. Those areas really stand out when we have a run of hot, dry weather with high E.T because they burn up quicker, tend to be more hydrophobic (so are harder to re-wet) because they contain mostly root matter which is naturally water-repellent and prehaps most importantly, the crown of the grass plant grows on the top of the fibre layer so is elevated and right in the firing line of high temperature stress.

The image below was featured in a presentation given by Bruce Clarke, Rutgers on Anthracnose during GIS2017 and was being used to highlight the benefit of summer topdressing and actually topdressing in particular when it comes to management of this disease.

You can see in the Poa annua plants on the left side of the image, the crown is growing on the surface and so is exposed to the worst of high temperature, not to mention wear and tear and the increased risk of coming into contact with the bottom blade during wetter conditions. The Poa in the centre and right has its crown deeper in the rootzone profile surrounded and therefore protected by topdressing.

Poaannuacrown

I’ve said it before and I’ll likely say it again but I think it’s sometimes a hard call to communicate to the powers-that-be why there is a requirement to aerate, topdress, etc when the surfaces that you are treating look fine. The reality is we are in the game of preventative maintenance, i.e we put in place preventative maintenance in order to keep the grass plant healthy and in so doing we are maximising the potential to present an optimum surface for as many days of the year as possible.OMMeasurement

So I guess the bottom line is that if you’ve noticed areas of turf be they golf green, outfield, sports pitch or lawn go under stress much faster or react differently to watering, then the first thing you should check out is the organic matter level you’re dealing with. For sure you can send samples away to a lab but this is costly and takes time. Just as effective (in my humble opinion) is to take a sample wedge with a knife and examine the depth and nature of the fibre. I’ve uploaded a Powerpoint presentation to show you how I do this and what I look for here

I’m not saying it is the definitive way but it works for me that’s all….

Looking ahead…

So we are now facing at least a week of rainfall following a prolonged dry and stressy spell…what can we expect ?

Well some good recovery for one provided nutrition and cultural is in place, so light aeration to facilitate gaseous exchange and water movement from the surface is a must if resources and time allow this prior to the arrival of rain.  Overseeding weak areas after aeration will also be beneficial and no place better than wear areas, tees, outfield and the like, but make sure you’re not just overseeding into thatch else you are not giving the grass plant much chance at all.

AnthracnoseTakeAll

Disease-wise I guess you don’t have to be a rocket scientist to know that we will likely see more disease over the next week or so with the increase in humidity / leaf wetness, with Microdochium nivale, Red Thread and possibly Anthracnose / Dollar Spot likely to raise their ugly heads.

A prolonged period of hot weather followed by moisture and humidity are potential calling cards for the development of Anthracnose and I expect this summer to feature high disease pressure from this pathogen after the trigger event at the end of May and the same at the end of June. Time will tell if I am right (in a way I hope I’m wrong) because unfortunately we won’t see the symptom until it is too late and the disease is present at an advanced (spore-forming) stage.

There is plenty that can be done from a preventative perspective and I’ll cover that next week.

In the meantime enjoy the cooler nights (better sleeping any way so there’s always a flipside :)) and all the best for the coming week.

Mark Hunt

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