April 7th, 2025

Hi All,

My apologies for no blog last week but I was installing down in Devon and The South West in beautiful weather. Installing a Davis weather station looking down on Plymouth Hoe in beautiful sunshine was a pleasure, I just wish I'd took my fly fishing gear ! .

Since the 19th / 20th of March, this has been the scenario, when the weather flipped and changed to bright, sunny and warm days, with very little rain and some pretty cold nights. Great for playing the game and certainly the car parks of the clubs I visited were heaving, but a little tricky when it comes to promoting consistent growth whether that be on golf greens or converting from winter season to cricket. (particularly if you have no irrigation in the latter scenario)

Last weekend, I had the 'pleasure' of attending my first football match for over 30 years at Aston Villa with two stalwarts of our industry , Mr Banks and Mr Edmunds.

It was a brilliant experience, such an atmosphere and I could see some of our greenkeeping colleagues attending to the pitch in the intervals. Now, I don't drink a lot of alcohol and indeed I am talking about a person who has a thick head the next day after drinking Guinness 00, so my start to Sunday was let's just say, a very subdued one ! Thank you Ross and Simon for the 'experience' and I look forward (I think!) to next year 😎

Nature is embracing this warm start to spring, with more Butterflies than I can remember seeing for a long time, Brimstones, Orange Tips, Peacocks and Small Tortoiseshells abound on my walks across Leicestershire and Rutland. As I have fished into the evening I have also seen a lot of Bats about and some fantastic Buzzer / Midge hatches. You know everyone was saying last year "what has happened to our insect population". Well we had a dreadfully wet and cool spring, that was the main driver in my mind and now with some warmth and sunshine, insect populations have rebounded strongly. On Friday, I saw my first Swallow flitting across Rutland Water and Maya the famous Rutland Osprey has already laid two eggs, good news. I do notice though that the crops in the fields, especially on lighter land look dry and growth retarded, short of rain and do you know, we could do with a bit of the wet stuff at some time soon.

So looking ahead to this week's and next week's weather, any sign of a change ?

7-day GFS projection courtesy of tropicaltidbits.com

General Weather Situation - w/c 07-04-2025

So the answer to that question is yes and no......

For this week we will see a continuation of the Omega Blocking Event that has been with us since the 3rd week of March. So that means high pressure continues to dominate and indeed as we progress through the week, we see temperature building as warm air vectors into the high pressure system. So we will continue the current trend of dry, warm and bright sunshine through this week, though eastern and northern areas may pick up more in the way of cloud cover. Across the UK, we will see temperatures rise into the high teens / low twenties, with Scotland in particular picking up some of those temperatures in the 1st part of the week. After a cool start to the week for Ireland, we will see temperatures build in the second half of the week towards the high teens. Looking further east, Denmark will continue this week to enjoy a nice, warm start to the spring with temperatures in the mid-teens and remaining mainly dry, though there may be some light rain around later in the week. More night frosts though I am afraid.

7-14 day GFS projection courtesy of tropicaltidbits.com

Weather Outlook - w/c 14-04-2025

As we approach the weekend, you can see the Omega shape (Ω) in the jet stream (marked by the dark green band) starts to shift eastwards and that'll trigger a change in our weather potentially allowing cooler and maybe more unsettled conditions to enter our weather picture. Indeed in the GFS image for the 13th April above, you can see low pressure is projected to make an appearance. So if you are wanting some rain, then the chances of seeing some increase from Sunday onwards. Critically we will also lose that easterly airflow, swinging round to the south (north for Ireland).

With current projections, Ireland looks to pick up some rain on Sunday and this rain will track northwards into Scotland during the day. Later we will see more of this rain into central and eastern areas with rain pushing into Jutland I think on Monday. So next week we will start the week cooler, but not cold, with temperatures in the low to mid-teens. More cloud cover means night temperatures will stay up and that as I have intimated before is critical to growth. More rain looks to make an appearance mid-week, next week and we will slip into a sunshine and showers weather format I think later next week.

Now, I'll throw a caveat in here, this prognosis is subject to change and looking at Meteoblue's current probabilities attached to this weather transition it is currently in the region of 15-20%. My hunch is though that it'll happen and the start of this process will be a wind change away from easterlies from Thursday this week. If we see this, then the process is underway.

Another give away that a change in the weather is on the way as I have discussed before is these tell tale - Mares Tail cloud formations, so look out for them as well towards the end of the week.

Agronomic Notes

Soil Moisture Status

So quite a lot to speak about in this week's blog, first up let's talk about moisture.

As the graphic above shows across Central England, the last appreciable rain was around the 23rd of March, so that's 2 weeks ago. At the same time March 2025 was a pretty dry month on the whole, especially across central and eastern areas. At the location above, we finished March 2025 with a deficit of 41.5mm between moisture from rainfall vs. moisture lost by evapotranspiration. We then continued this moisture deficit into April as temperatures climbed, wind strength increased and we lost more moisture by E.T, with a further 19.4mm so far this month and the trend set to continue.

So that's around -60mm of moisture deficit by the 7th of April and I think that will climb another 15-20mm by the weekend. A soil moisture deficit of -80mm at this time of year is appreciable. Now of course there's a lot of variability geographically and it is impossible for me to summarise it in this blog, but ostensibly we are pretty dry, especially on the surface (moisture levels remain good)

Furthermore, a daily E.T loss of 3-3.5mm is significant and has meant many facilities have had to reach for their irrigation especially early in the season. Now don't get me wrong, I am sure we would all take this scenario from a turf management perspective vs. the one we had last year at the same time, with excessive rainfall, low light and cold conditions. At least here we have some control over one of the factors, soil moisture. With many facilities utilising soil moisture meters, we are also in a much better situation, rather than just irrigating 'on spec' because it is dry, we can see how the soil moisture is behaving in relation to E.T and react accordingly.

It isn't just about looking at numbers of course, your turf will tell you when it is suffering with soil moisture deficit displaying as plant wilt (shown above).

Good turfgrass management to me is dove-tailing data and agronomic observations together, what are the numbers saying, what is the turf saying ?

Up and down growth.....

When we have this kind of start to spring, it often brings with it pressure on the turf manager.

This is because of perception on behalf of management and members alike. To put it simplistically, the sun is out, its warm in the sunshine, surfaces are dry, the birds are singing, the grass is growing (isn't it ???) and all is good with the world.

The reality is slightly different to the turfgrass manager who is cutting with frost on the rollers at dawn.

Maximum & Minimum air temperature vs. Growth Potential - Bristol

Above is a graph of minimum and maximum air temperature vs. daily Growth Potential for March and April 2025, using data from a Davis Vantage Pro located near Bristol. You can see how the maximum air temperature increased significantly from the 20th of March climbing 10°C in 24 hours as did Growth Potential (G.P), which previously had been bumping along the bottom of little or no growth. As a guide, a G.P >=0.4 represents in my mind of good spring growth, with substantial clip in the box, recovery from winter wear and tear, you get the picture. So for the 38 days covered in this graph, we have had 10 days with a G.P>=0.4.

Not bad but not a consistent 10 days because less than 4 days ago, this location had a ground frost which dropped the G.P down to 0.3. That is 30% of optimum.

So whilst the sun has been shining, the cold nights and cold starts to the day have actually resulted in a pretty low daily growth pattern. Not dire by any means, but if you're looking for seed germination, recovery and tillering, you'll be making slow progress.

Maximum & Minimum air temperature vs. Growth Potential - Silkeborg, Denmark

Now let's jump eastwards and look at how that same maximum / minimum air temperature dynamic is playing out vs. daily Growth Potential on Jutland, Denmark.

Here the temperature scenario is even more marked with decent day temperatures climbing to 20°C on the 3rd of April. On that same day, the daily G.P was only 0.24 or 24% of optimum. In the last 68 days, there hasn't been one with a G.P>=0.4, i.e good growth.

Why ?

Well, because although the maximum temperature was a heady 20°C, the minimum temperature was -1.7°C. Indeed for every day in April so far at this location, we have seen nightly air temperatures below 0°C, with a low of -5.3°C last night.

So, although everything is nice and dandy during the day for the punter, the pleasant day temperatures are more than counteracted by very cold night temperatures and a growth potential that is hardly registering. This scenario may change later in the week when we may pick up more cloud cover, a southerly airstream and an end to those night frosts. In the meantime, we will have to wait for growth and recovery and be patient.

Leatherjacket activity

On my travels recently I have seen a good amount of Leatherjacket activity (thanks Ben for the pic) , with grubs appearing on turf surfaces or turf damage from Foxes, Badgers and Corvid species. Crows and Rooks now have young in the nest so they're especially keen to get at these grubs and that presents a problem. Obviously with a mild run in to Christmas, these grubs have put on fat reserves and that has allowed them to survive the colder temperatures since the start of the year. A giveaway sign if you have aerated recently is a countersunk appearance around the edge of tine holes where the grub emerges at night and feeds on the surrounding grass. One to keep an eye out for me though there is little that can be done at this time of year as far as I am aware.

Now don't get me wrong, I'd take this start to the year over last years wet, dull and cold one any day of the week. It's good for the soul, it's good for nature and it's good for business. In this world of uncertainty, the latter is very important, feeling some warmth on your back is nice as well and for insects and bird life, this is a nice start to the year, so let's enjoy it, but at same time remember that grass growth is just ticking along at the moment and patience is a virtue.