161128_gfs_pres_500p_loop_eur

Hi All,

Wow, hasn’t November flown by, this week we tip toe into December and our last month of 2016. And the good news is that rather than high pressure breaking down this week into a cold, northerly low, we look to carry on this dry and settled weather throughout the whole week 🙂

That will be especially good news for everyone that had the tumoltuous rain at the beginning of last week that caused flooding and closed venues particularly down the south west of England and Wales. We had 50mm here over the two days including one period when 14mm fell in 30 minutes, but I know some of you hit over 100mm in the south west. Ironically Ireland where I was last week missed all of it for a nice change and was cold and dry 🙂

So without further ado, onto this week’s weather…

General Weather Situation

So for Monday we have a cool, dry day pretty much everywhere across the U.K and Ireland with some cloud cover in the south of England keeping temperatures over freezing through the night. The further north you go, the more likely you are waking up to a frost on the ground. As we progress through the day, this thin layer of cloud breaks to give long spells of winter sunshine. Temperatures will be mid-single to high-single figures and the wind will maintain its easterly orientation, light to moderate in places.

Clearing skies and a winter high pressure system mean only one thing and that’s frost going into Monday night / Tuesday morning from the north of England south likely to be worst affected by much will depend on cloud cover in your location. Ireland and Scotland look to retain some cloud cover so you may miss a ground frost here. During Tuesday morning, a weak rain front is set to push into north west Scotland and sink slowly south along the west of Scotland bringing light rain, sleet and snow to higher ground. By tea time it has fizzled out to just a few snow showers over the Western Highlands. With thicker cloud cover over Ireland there’s a risk of some mizzly rain for Donegal and Connacht during the morning as well. Away from Scotland and Ireland we look to have another cold, bright and dry winters day with a penetrating frost in the south of England I think. Much lighter winds now, south to south easterly in orientation and similar temperatures with nowhere likely to break double figures. By the evening we see cloud cover extend south over northern England and The Midlands.

Moving onto Wednesday we have clear skies and another ground frost across the south of England right up to The Midlands and inclusing South Wales. Further north for northern England, North Wales, Scotland and Ireland, the cloud cover may just prevent a frost again but morning temperatures will be close to freezing nonetheless. From dawn expect to see some more rain in the far north west of Scotland and thicker cloud which will sink south to give heavy drizzle / light rain again across west and Central Scotland during the morning. Aside from this, the south and east of England looks to see most of the sun on this day with cloud cover and hazy sunshine for more central and northerly regions. By Wednesday evening we see another weak band of rain and thicker cloud push into Scotland and move slowly south pushed along on a freshening moderate to gusty westerly wind now. Despite the change in wind direction to westerly I don’t expect to see much milder temperatures for Wednesday with mid to high-single digits the order of the day everywhere.

Moving onto Thursday and we see more in the way of cloud cover in general for the U.K and Ireland with that weak rain front persisting over Northern Scotland pretty much through the entire day. Areas with overnight cloud should just miss another ground frost on Wednesday night / Thursday morning. A cloudier day everywhere then for Thursday with a moderate to gusty north west wind in situ as well, possibly stronger in the north I think. That cloud cover will raise temperatures just a little to high single figures but nothing to write home about really. A dull, dry and cold day just about sums it up.

Closing out what looks to be a fairly uneventful week meteorologically-speaking, Friday looks to be a re-run of Thursday with cloud cover over most of the U.K and Ireland. Again we will see some rain over the far north of Scotland and along the north east of Scotland in particular. That is the exception to the dry picture everywhere else though but with thicker cloud we could expect to see some mizzly drizzle along north eastern coasts as well. Dull with a capital ‘D’ just about sums it up, but crucially ‘D’ for dry and that’s what matters at this time of year in our game doesn’t it ? Winds will be lighter on Friday and from the north west still, but set to change I think.

Looking ahead to the all important weekend and the annual trudge around the shops looking for Black December bargains on goods that will cost you less just a day after Christmas (You’d think we’d wise up by now wouldn’t you?) or alternatively boot up the PC, do it all online while sipping a cuppa and miss out on all the crap associated with Christmas Shopping (Bah Humbug I hear you cry) .  Well it’s going to be cold, dry and perhaps a tad brighter in the south of England on Saturday / Sunday.  Winds will be light and a mixture of easterly for the south of the U.K and southerly for northern regions. Ireland looks to be a tad milder with some sunshine through the weekend and higher single figure digits for you 🙂 Again we’re dry and for that we can rejoice, get up early and go for a lovely winter walk with frost likely to be crunching under your feet on Sunday morning in particular if Saturday night is clear of cloud for you. (That’ll be my modus operandi for sure now I’ve put the fly rods down for the winter 🙁 ) Expect mid-single figures at best in most places and a change to light westerly winds on Sunday.

Weather Outlook

So is it possible that with nearly two weeks of pretty dry weather tucked under our belts coming into December we can continue the run ? Remember last year we scarcely had two days of dry weather during November and December !

I think realistically the odds are against it however if you look at this weeks prognosis, last week we were set to plunge into a very deep low pressure system and instead this has been pushed down to the east of us into central Europe and we have got high pressure. Next week this high pressure is under attack from two sides, the north west and the north east but ironically that could mean it stays in situ, squeezed between the two. Not before some unsetlled weather though.

So next week looks like starting as we finished with high pressure in charge but they’ll be a change on the cards as the wind will swing round to the south west during Tuesday with western areas (Ireland) feeling that change first.  South westerlies in winter mean mild and wet and so I think we’ll see rain for Ireland next Tuesday and this will push diagonally up into Scotland through the course of Tuesday. By Wednesday I think the rain will be into Wales and the remainder of the U.K, possibly clearing Ireland and Scotland as it does so. It will feel much milder across all areas with that Atlantic air stream. By Thursday the main rain band should have passed with perhaps still some unsettled weather further north but we now have high pressure beginning to re-exert itself so that means cooler with a change to a stronger, more northerly air stream by the end of the week so pretty Baltic by the weekend after next I’d think if that pans out.

Agronomic Notes

Root Growth and Winter Aeration

roots

Now I know a lot of you are busy wth winter projects at present and enjoying the dry conditions of last week (after the rain) and this coming week but if you have time then now I believe is a good time to encourage root growth. The schematic above is simplistic of course and I think out-dated because our seasons don’t always (often) follow the ‘roots in spring, lose them in summer and build them in the autumn’ rules of turfgrass root growth.

When we have cool, dry conditions with mid-single figure air temperatures we often see very little shoot growth (top growth) with mowing taking off a dusting in the boxes but that doesn’t mean the plant is not growing. So whereas shoot growth takes a back seat at these sort of temperatures, root growth carries on right down to freezing I think with the cooler season grasses. How many times have you laid turf on the ground in cold conditions only to see new roots pushing out of the surface fibre into an oxygen-rich atmosphere ?

rooting

So using the vertidrain or other deep soil decompactors is I think appropriate at present if your ground conditions allow you to do so. For those of you who were caught with the 50-100mm of rain early last week  this may not be an option but it’s amazing how quickly surfaces have dried since that rain with the windy and cool weather after the rain event.

In order to make these roots the plant will need some nutrition in place and hopefully this was in order prior to this week because with frost in the early part of the week it won’t make planning a light feed in easy, much will depend upon cloud cover and the potential for night frosts. This is where longer-term winter nutrition really pays for itself because if the plant has nutrition available prior to this period of cool weather (i.e nutrient was taken up when it was milder) then it will partition this nutrient towards the part of the plant that is likely to grow. In this case it is biased towards root growth rather than shoot growth.

Why haven’t I got much root ?

Achieving and more importantly keeping good root development is I think one of the hardest challenges of turfgrass maintenance.

There are numerous factors that affect root growth and any one of them can contribute to poor rooting even though others are firmly in place within your maintenance program. I’m not going to run off a list of all of them but briefly cover the one that I find on my travels contributes most to shallow rooting.

Surface Organic Matter

thatchhabit

Definitely the most-often cause of poor rooting in my books. Not just depth of surface organic matter but more often than not the nature of that fibre. What I mean by that is a compacted surface fibre layer with low amounts of topdressing sand integrated through the profile will present a tough, physical barrier for root development. You can very easily look at this yourself by cutting out a wedge from your surface and pulling it apart slowly. If you see white, lateral (horizontal) roots then there is clearly a barrier to vertical root progression down the profile. Take the tip of a knife and push it into the area under the surface and assess the resistance. If it is firm and difficult to penetrate then that is why you have shallow rooting. It will also be the reason why you’ll see very little benefit from overseeding because if the existing plant can’t develop a root down through this compact fibre layer, how do you expect a new plant to do so ?

A little story…

I once visited a site where they were overseeding fairways and they had just such a layer in the surface and they were overseeding with a Fescue / Rye mix. They had no fairway irrigation and were a very dry site, often experiencing some of the highest temperatures in the summer. After a very good autumn take from drill seeding I expected great results going into the summer, confident that the drought-tolerance of the Fescue would perhaps tip sward populations in its favour. The summer was hot with temperatures in the mid-thirties for an extended period in July so when I visited in late August I was interested to see how the newly-overseeded sward had stood up. The answer was not very well indeed and conversely the plant species that had survived best was Ryegrass, not Fescue.

Why I wondered when we all know how drought-tolerant the latter species is ?

The answer was related not to drought tolerance but plant vigour. The ryegrass had managed to push its roots down through the surface fibre layer and into the clay beneath and survived because it is a more vigorous species. The Fescue had not developed roots through the fibre and so was subjected to the worst of the heat and moisture stress. A lesson learned for me, not just in terms of drought tolerance, but also plant vigour and the role of surface fibre on rooting. The latter isn’t anti-Fescue, it’s a field-based observation from one site that illustrates the role of surface organic matter in the success or otherwise of overseeding.

Organic Matter Distribution

If you do check your surfaces, don’t just pick one place on a green for example because surface fibre depth will vary according to traffic routes with heavier traffic routes showing less fibre than less used areas. (see image above)

Thatchfungusgreen2

One last point on surface organic matter if you are seeing thatch fungus. In my experience there are species of Basidiomycetes that are active right down to low single figure temperatures so don’t be surprised to see evidence of Superficial Fairy Ring and Thatch Collapse during the coming winter months.

Disease Activity

With humidity levels falling through last week after the rain event and continuing to drop now into the 80’s, it will mean a lowering of disease pressure everywhere I think. I can’t stress enough how having a wet plant leaf is a driver for pathogen development but with high pressure in place and a continuation of drying winds through this week for many, I think we will see disease pressure drop off nicely. If the forecast is accurate and we pick up milder, wetter weather for a portion of next week then that is the time to watch carefully for any ‘flare ups’ particularly on existing scars. It would take a brave man to say we are through the worst of it but I think with the way the winter has played out so far and no set jet stream pattern on the horizon to flip us into mild and wet weather, that may indeed be the case. On the flipside if you have heavy scarring and therefore a high disease population in situ, you will see periods of activity from now on 🙁

OK that’s me done for another week…

All the best…

Mark Hunt