Hi All,

It’s inevitable living in Leicestershire that you follow the many rises and falcfclls of Leicester City Football Club always hoping to see them strive. Last year they dodged the bullet of relegation by the skin of their noses and this year they have simply been a revelation. A revelation that goes against the grain of popular thinking that money spent on players is the only way to achieve success in the modern game. I wouldn’t call myself a supporter because I only used to attend the games as a spotty teenager but I am a fan and a proud one at that . And to all those people who say “you know nothing about football”….You know nothing about football 🙂

The last week has seen us LawnMay1stserved up with some of the barmiest weather to date and this week we will have some of the balmiest to date as we predictably go from winter to summer and forget the spring thing in the middle 🙂 Last Wednesday I was out for a quick evening walk and could see from the rain radar that a storm was close by, what a storm it was, there was thunder and lightning, hail and then it was topped off with snow. I got sent a lot of nice winter pictures from all over but I particularly liked this one below from Dave H entitled Bank Holiday Forecast…The chap on the right reminds me of a colleague 🙂


Ok enough of the frivolity, onto the matter in hand…

General Weather Situation

So I am going to start the forecast from Wednesday because this is going to be a long blog and by the time you receive it, it’ll be late on Tuesday me reckons 🙂

So overnight into Wednesday we see a weak band of rain moving in from The Atlantic into the west coast of Ireland / north west coast of Scotland. Away from this it’ll be a cool night if skies are clear and this may especially be the case for Central and Eastern England. That rain makes slow progress and so by the morning rush hour straddles halfway across Ireland and doesn’t make it much further inland across Scotland either. Close to this rain front they’ll be plenty of cloud in evidence but east and south of this (which is most of the U.K) will see clear skies and sunshine from the off. With this temperatures will rise quickly to mid to high teens in places with perhaps more in the way of cloud later in the day. Ireland will have a dull day with light showers as that rain front makes slow progress across the country and here temperatures will be more like low to mid-teens. Winds will be predominantly from the south west and light to moderate.

A mild night for Wednesday with no risk of frost except over The Highlands of Scotland and as we progress into Thursday we see any rain over Ireland and Scotland fizzle out and more in the way of cloud cover drift in to all areas with perhaps only the east coast starting the day bright. It’ll be a dry, hazy sort of day on Thursday with light south westerly winds but much more in the way of cloud cover for all areas. During the day those winds will swing round to the south east and this will usher up warmer air from the continent. For this reason temperatures will continue to rise as we progress through the week reaching high teens in England and Wales and mid-teens for Ireland and Scotland. In short a lovely day again.

Closing out the week we see a continuation of that trend of building temperatures courtesy of that south easterly wind pushing up warm air from the continent. There is a risk that this may trigger off some thunderstorms later on Friday but possibly more so over the weekend. In the south of England I expect temperatures to hit the 20°C mark during the day and for Wales, central, northern England and Scotland to be well up there in the high teens. Unfortunately for Ireland you get the slightly muckier end of the stick because you’ll be the other side of the low pressure and that means rather than a south easterly wind, yours is more likely to be north easterly and that will pin down the temperatures to the low teens I’m afraid. The same is likely to be the case for The Highlands and north of Scotland and here you may see some thicker cloud and rain as well.

Onto the all-important weekend 🙂

Saturday looks to start off nice with a mild night and temperatures rising quickly however there’s moisture on the way from the continent and that spells rain and possibly thundery outbreaks in my books as moist air and warm air meet. Now you’ll remember that continental rainfall is extremely unpredictable and therefore difficult to forecast correctly but at this stage it’s looking like it’ll push into south east Ireland by late morning and into the south coast of England by lunchtime. I expect that to change for sure. So Saturday looks like being a dry, warm day in the morning and a wet p.m. for some. Since that rain is coming up from the south, it’ll reach the north of England and Scotland later in the day and there’s also a suggestion that the east coast of the U.K may miss it altogether. Temperatures will remain up though so mid to high teens in most places of the U.K, lower though still for Ireland because of the prevailing wind direction. Sunday looks to follow a similar pattern with plenty of rain around for Ireland, Wales and the west coast of England / Scotland. Again the suggestion is that this rain will be more westerly focussed so eastern areas may get lucky and have a warm and dry day. With more in the way of rain and cloud around for Sunday we will see temperatures dip to the mid-teens for England, Wales and Scotland, but crucially the night will be  mild. Winds will remain south easterly for the U.K and on Sunday, Ireland will see their wind shift to southerly and then south easterly bringing with it milder temperatures.

Weather Outlook

Ok so now we have our first taste of warm weather, will it continue and make up for what was a truly dismal April ?

Well I think yes we will continue to see that warmth next week with a south easterly / easterly air stream in place and perhaps it’ll get even warmer across the east and south of England in particular. Of course a continental air stream means we are likely to see some rain as well, more so I think earlier in the week and probably more central and southern England-orientated. Some of this rain may well be thundery in nature, another feature of continental weather of course. We look fairly well set for a warm week and I’d hope a continuation of milder nights as well because that’s what makes everybody’s life less stressy.

Agronomic Notes

Growth in terms of Growth-Degree-Days

Before I set off down the path of comparing this April with last for all the usual locations I want to explain why I think this is relevant to what we do, whether you’re a groundsman, greenkeeper or contractor. Growth-Degree-Days is a measure of the potential for the grass plant to grow and it provides us with a clear method to compare seasons and thereby provide a factual basis for how the areas that we maintain are growing or not growing as the case may be.

I say ‘not growing’ because we all know the scenario we face every spring when we get mild days and cold nights. The punter expects this means good growth whereas when you are cutting and there’s frost on the rollers you know different.

How do we communicate this though ?

Well that’s where GDD and Growth Potential come in.

So let’s compare two different types of day in April and see how they pan out GDD-wise…


So in scenario 1 we have a nice mild day with the air temperature reaching 17°C, but it started out cold with an overnight frost down to -2°C. If we do our sums using these minimum and maximum temperatures and the formula below we can calculate the daily GDD ;

GDD = ((Max Air Temperature + Min Air Temperature) ¸ 2 )  –  (Base Temperature °C )

Now I use a base temperature of 6°C because that’s when we start to see grass plant shoot growth and that makes sense to me as a logical base temperature. Some of the U.S models use a base of 0°C and that doesn’t make sense to me because the formula will return a GDD value even though nothing is actually growing.

So in scenario 1 if we do our sums we return a GDD figure of 1.5, which is very low bearing in mind a GDD figure of 0 means no growth at all.

Let’s look at another day in April, scenario 2 when we have a nice mild day with a similar maximum air temperature of 17°C, but we also had a nice, mild night with the temperature not dropping below 8°C.

In scenario 2 if we do our sums we return a GDD figure of 6.5, which I know from my field observations correlates to reasonably good spring growth.

If we look at it from a factual basis the grass plant has over four times the potential to grow if the temperatures follow scenario 2 than scenario 1. (6.5 divided by 1.5) That’s the rub, that’s fact and can’t be argued with because we know GDD calculations correlate well with grass growth until we reach a point where the temperatures get so high that they cause plant stress (not likely at the moment)

So hopefully you can see why I think GDD is a useful parameter to sort the wheat from the chaff when we talk about grass growth and particularly when we look at spring growth.

So how was it for you ?..April that is…….

So let’s see how our GDD’s pan out….starting with our Thame location and comparing 2016 with 2015…


First up you can see how the GDD curve for 2016 flattened out at the end of April compared to the previous year which highlights the fact that growth stopped at the end of this April 2016, due to the blast of Arctic air.

Looking at the daily growth pattern through the first four months of 2016 and bearing in mind a daily GDD figure of 6 or above represents good growing conditions, you can see what I mean about poor growth.


So in this location for the whole of April we only had 3 days approaching reasonable growth. (close or over the red horizontal line) and practically no growth from the 21st April to the end of the month.

You can download this on a pdf here

Comparing 2016 with the recent past…


Looking at the historical data above for the Thame location we can see that April 2016 provided us with the 2nd lowest monthly GDD total of the past 6 years and lower even then the long winter of 2013 ! On a cumulative basis we are just ahead of 2013 y.t.d but that’s only because January and February 2016 were so mild.

If you take March and April together from a total GDD perspective and compare with previous years, here’s how 2016 stacks up….

Total GDD March + April

2010 – 153   /  2011 – 233    / 2012 – 116   / 2013 – 85   / 2014 – 197    / 2015 – 130    / 2016 – 82

It’s official then, the lowest growth as measured by GDD over March and April that we have recorded….

UK and Irish Locations – How they compare

Before I comment on this, I’d really love some Scottish data from the east and west coasts to comment and contrast with the other data I have, so if anyone’s willing please drop me an email on mark.hunt@headlandamenity.com


Looking at the 5 locations I have data for you can see the influence of geography in terms of the London location is that much further ahead of the central and northern England locations in terms of GDD. It must be all of that hot air coming out of the Houses of Parliament 🙂

Across the Irish Sea the picture looks like this…

GDDIRISHJANTOAPRIL2016_2Of course Valentia is doing its usual job of streaking away with the game because of its south westerly location. Up country the locations are more similar this year with Wexford currently sitting up front and Ballyhaise just lagging behind a bit.

If you compare the U.K to Ireland in terms of GDD, you can see how similar they are really and it makes a mockery of the pesticide regulators assertion that the Irish climate is so different to the U.K’s….

Taking advantage of this weather window and some of its consequences….

Ok to tackle this subject I’ve cut and pasted Meteoturf from my location for the next 7 days and highlighted what I want to talk about…


First-off you’ll notice both the GDD total and the pattern in the Growth Potential chart.

The total at 46 for the next 7 days is high (bear in mind last week the total was 5!!)  and the chart shows an upward trend in growth as we progress through the week. So this suggests to me that we are going to experience quite a flush of growth particularly over the weekend so it may mean coming in next Monday morning to a lot of grass unless you have the resources to take action (and I totally accept this isn’t pertinent to everyone)

Predicted Growth Flush – PGR Slot

If I had to make a choice when I applied a PGR to outfield areas, this week would be THE WEEK for me to get as much ‘bangs for my buck’ out of the application because we have good soil moisture levels, rapidly climbing soil and air temperatures and therefore optimum conditions for growth or more specifically growth suppression. Now if you need recovery on outfield areas you could go at a half rate and slow that growth down a tad and increase tillering at the same time.

For fine turf that growth will be welcome..

On fine turf this growth uplift will I think be very welcome because we’ll see the purpling of late grow out quickly and Poa, Bent and Fescue will all get a good kick up the jacksie so that differential growth where one species is growing and another one isn’t should become a thing of the past quite quickly.

Great Uptake Conditions for Selective Herbicides…

The warm weather, dry conditions (for most) mean that it’ll be an ideal time to get out with a selective herbicide if you’re planning on making an application. Uptake will be fast and efficient.

Lots of plants will be flowering very quickly 🙂

If you haven’t seen many of these yet ….






You will soon because with many locations sitting between 100-120 GDD, we will quickly put on the 20-30GDD this week required to take past that 130-150GDD threshold that signifies the Poa annua seedhead flush. So be prepared for a lot of seedheads appearing very quickly.

You’ll also see a lot of broad-leaved weeds spring into growth and flower this week hence the advice about selective herbicide application.

Microdochium nivale – Fusarium in old English..

Just as we can expect to see a rapid increase in grass growth I also expect us to see a flush of disease on fine turf. Fortunately we should be able to grow it out as quickly as it comes in…

We will dry out and fast….

The 2nd part of Meteoturf’s prognosis for the week ahead concerns the anticipated E.T loss of 24mm over the next 7 days. Now for some of you, particularly across the north west of England and Scotland this will be manner from heaven because it means you’ll be drying out big time and that’s just what you guys need after an agonisingly wet winter and spring. (not to mention the cold temperatures as well)

For locations in the south and east though where rainfall levels have been lower it means you’ll see turf dry out very quickly indeed so it’ll be a real balancing act dealing with a rush of growth and high E.T demand.

That’s why I think a PGR application will work well because it’ll hold back some of that growth and thereby slow down the moisture requirement of the grass plant.

So this week we will see a quick transition into hand-watering and if next week’s temperatures pan out as projected this will continue and possibly escalate.

Barmy and Balmy

It’s perhaps a reflection of our rapidly-changing climate that we are likely to go from snow one week to 20°C the next but it doesn’t make turf management very straight-forward does it ? 🙂

May the sun shine warm upon your face 🙂

All the best

Mark Hunt