April 12th, 2021 !

Hi All,

First up, sorry for the mix up last week when some of you clicked open the blog link only for it to transport you back a year to the same day in 2020. Therein lay the problem because the blog link format was date only (rather than year and date) and since I did a blog last year on the same date, it went straight to that output. Great work from Paul Vipond, our super business support chappy to put it right and stop me fretting ! Cheers Paul….rest assured the date format has now been ‘modernised’ 🙂

Had some lovely Christmassy pictures sent in over the weekend and this morning from my erstwhile colleagues Alex (who lives somewhere high up in Yorkshire) and Iain who resides just off the M40. That area got a clattering of snow this morning from a heavy wintry front which edged down the M40, across the M25 and onto the south coast. Thanks lads but with a warm (ish) soil it won’t be hanging around for long !

I had a lovely weekend walk around Rutlands peninsular, well actually it was a bit of a bummer as well because yesterday was the Rutland Half Marathon that I trained for in 2020 and then it was cancelled and now I’m carrying an injury that will probably end my running days so to walk past all the mile markers was sad. Not much time to wallow in self pity though because it was real Crowded House weather (Four seasons in one day). On the walk up to the peninsular it snowed with strong winds that numbed half of your face. But on the other side, the sun was shining and the air was absolutely alive with buzzers (midges), Swallows and Sand Martins. Literally hundreds of them gorging after their long trek up from Africa. You could almost sense the delight in their movements and happy twittering to each other as they lined up on the telegraph wires for a quick break.

Absolutely beautiful and a tonic for the soul.

So will our wintry showers continue or is there any warmth on the way ?

General Weather Situation

So as commented on above, Monday morning starts off Christmassy white for some folks as that band of snow moves down the M40 into southern England. It’ll soon be gone in most places. Elsewhere we look to have a dry, bright and frosty start with temperatures here at -2.7°C overnight. Ireland will see some showers into western areas of Connacht and Munster and these will push south and east through this morning towards Cork. Across The Irish Sea, most areas look to have a dry, bright and cold day with just the odd wintry shower pushing in across North and West Wales into western areas of England. Winds will be light to moderate and from the north west which will allow temperatures to pick up to the standard 8-10°C that we seem to have been stuck in for months now.

Overnight into Tuesday and we look to lose those showers across Ireland and start the day with another frost for central and eastern areas as cloud cover will keep temperatures just high enough for the western half of the U.K and Ireland to avoid one. A real west-east divide on Tuesday as Ireland and the western half of the U.K sits dull and dry under cloud cover, whilst the eastern half of England and Scotland looks to be cold, bright and sunny. Some showers will push into Northern Ireland on Tuesday and if anything consolidate with the odd one pushing into The Western Isles as well. Light to moderate north westerly winds so yes you guessed it, 8-10°C is the order of the day…..yawn..

Mid-week beckons and actually this forecast will cover Wednesday and Thursday because there’s little to choose between them. Both days looks to start bright and dry after overnight light frost with early cloud cover for the north and coastal areas. This will soon burn off to give some lovely spring sunshine but we will see a change in the wind direction to easterly on Wednesday and that’ll add some further wind chill to what will be a chilly day with temperatures struggling into double figures in the west and lower in the east. The same for Thursday really but just with a stronger easterly wind adding to the windchill and seeing temperatures struggle once again.

Friday sees an Atlantic rain front try to edge into the west of Ireland but it’ll be rebuffed by the high pressure system sitting over the U.K, so maybe only Galway, Sligo and Kerry coasts will see some showers ? For the rest of us, it’ll be another dead ringer for Wednesday and Thursday with easterly winds, cold, bright and dry. Some areas will pick up just enough cloud cover to avoid an overnight front but again it’ll feel on the cool side with the habitual 8-10°C temperature range again the norm.

I’ll be glad when this weather looks to change because I know it’s not what you want to read and it’s getting pretty boring now Joan (This Country ref…)

So what’s the outlook for another hippity hop and a hang dang doody April weekend when the pubs are open outside ?

Well we will still have a keen easterly wind in situ so anyone who is contemplating a nip across east to walk the fabulous beaches of Holkham, Norfolk should take a good set of winter clothes !!!!

Actually the weekend looks like we will have more in the way of cloud cover, some sunny intervals and this cloud cover will negate the night frosts and allow us a milder start to the day and temperatures roaring, ok, creeping into double with 10-12°C likely on Saturday and Sunday and hopefully no night frosts. Ireland will see that Atlantic front edge rain into western counties on both Saturday and Sunday mornings before it retreats back out into The Atlantic to leave cloud cover behind. Towards the second half of Sunday, that rain establishes a foothold across the west of Ireland and pushes inland through Sunday evening. For England, Wales and Scotland though, another dry one.

Weather Outlook

So how are we looking for the next 7-10 days ?

Well mainly dry looking at the GFS output above I’d say with Monday next week offering the only chance of some of Sunday’s Irish rain pushing into Scotland and then down into northern England before fizzling away through Monday / Tuesday. High pressure then reasserts itself again and funnels into easterly winds however these will be slightly warmer than we will have this week so I’m expecting temperatures to slowly rise as we go through next week into the mid-teens possibly, with better night temperatures. So continuing that dry sunny theme for April, cool and unsettled in the west and north at the start of next week but remaining dry, bright and sunny with perhaps less in the way of overnight frosts and some better growing weather possibly provided you irrigate.

Any sign of significant rainfall ? Well maybe not till the end of April and that’s too far away to count on at present but it wouldn’t surprise me if we finish cold and wet for the end of April.

Agronomic Notes

So first up despite the fact we are enduring hard frosts and in some areas, snow on the ground, we will still get the inevitable question regarding lack of growth, blardy blah from people recently released from their hermetically-sealed cells 🙂 Don’t expect to get as many comparisons with Augusta this year though when the greens looked the colour of most car parks because they (quite rightly) dried them out in order to avoid the same criticism as last year. Firm and fast they were and with the continuing lack of rain, you can of course choose to present yours exactly the same 🙂

Irrigation will be I think a hot topic this week because despite the cooler temperatures we will continue to pick up significant E.T, so areas will be drying out fast. This is especially true following on from last week when the wind was so strong that most irrigation systems would be applying water into the next county and therefore unable to counteract the high daily E.T figures we experienced.

So we get the annual debate about not wanting to irrigate the greens because it’ll cool them down and slow growth…. stifling another yawn here…

Well you could argue that the grass plant isn’t growing much at the moment anyway as can be seen from this MeteoTurf print out from The Oxfordshire. I’ve used this location because it’s the one I quoted last week when we looked at 2021 vs. 2020 cumulative growth potential discussion. You can see that with night frosts and / or low temperatures to start the day, the Growth Potential is sitting around 0.1 per day, so that’s 10% of optimum growth potential per day, this week. On a positive note, you can also see that the situation begins to improve from the weekend as we lose those night frosts and pick up a warmer high pressure system next week.

I repeated the graphs from last week for both the Thame and Casement locations and added the projected temperatures / G.P looking forward to the 25th of April and you can see how difficult a growth month April 2021 has been in the U.K, with the flat shape to the graph.

Note a flat aspect to a cumulative graph means no incremental increase in cumulative values and hence little growth when we use it to measure G.P.

Here’s how the graph looks for Thame ;

Cumulative Growth Potential 2021 vs. 2020 up until April 25th – Thame, U.K

So you can see we are projected to sit around 17 days behind last April as we approach the end of the month with very little growth occurring this week but on a positive note, a predicted pick up next week.

Here’s how the graph looks for Dublin using Casement actual and projected data ;

Cumulative Growth Potential 2021 vs. 2020 up until April 25th – Casement, Dublin, Ireland

Not such a bad picture in Ireland in terms of 2021 vs. 2020, but you can see how April 2021 has fallen behind April 2020 due to the colder weather last week and this week with night frosts. Again there looks to be a positive pick up next week.

To irrigate or not to irrigate….

On the subject of irrigation, you could easily argue that if the grass plant is near dormant, it won’t need to take up much moisture to support growth, cell turgor and the like.

That said, it is losing moisture by evaporation through the stomatal pores to a point where it will probably hunker down anyway in moisture-loss shutdown mode this week.

That’s all well and good but as we pick up milder temperatures from the weekend, it’ll want to grow and it won’t be temperature that’s limiting growth, but moisture, especially in the top 25mm which we know is the region that dries out so quickly in the spring.

Below is a readout of April to date from our Great Dunmow, Essex weather station.

Quite a contrast between total rainfall and total E.T !!!

So you can see we have lost 29.73 mm of moisture by evapotranspiration from April 1st up to and including April 11th, with no replacement by rainfall.

(“Bloody rain went around us”…® …Copyright statement from every greenkeeper and groundsman who wants rain)

Here’s the effect of that E.T on soil moisture measured at 25mm depth on a high sand content rootzone at the same location ;

Soil moisture at 25mm vs. hourly E.T rates – Great Dunmow, Essex

So you can see the moisture dropped from 17.5% to ≈11% with the very high daily E.T levels we experience at this site. It levelled out because I ran some short programs to try and keep things ticking but with high wind speeds it made coverage inaccurate and did not resolve the very low vmc levels. We were nearly on wilt point at this stage I reckon.

On Saturday afternoon I came in from fishing, powered up the Davis and Rainbird IQ4 apps and could see firstly it was mild (ish) but crucially the wind speeds were low, so I might have a chance of decent coverage / wetting up the profile. You can see how effective it was from the graph above !!!!

I was a lot more relaxed after seeing the sensors respond and knowing the plant was happy 🙂

So we get that old Chestnut, yes but with cold water you’ll drop the soil temperature and slow growth…what you mean the growth that’s already been slowed by the lack of moisture ????

Soil moisture at 25mm vs. soil temperature at 25mm – Great Dunmow, Essex

So here is the same graph but showing soil moisture vs. soil temperature and I’ve highlighted the period when irrigation was applied. The soil temperature before irrigating was 9.2°C and after it dropped to 9.0°C, before dropping down quickly as it does in the afternoon / evening. So if you are able to put a cycle on, then do it when the soil is warm and you’ll have very little negative influence on soil temperature. OK, fine for you Mark to be able to do this, our golf club is heaving from dawn to dusk…..So my advice would be to wait till we pick up some better night temperature at the weekend and put on a morning cycle before the golfers arrive….Or just go round and manually run a cycle between the golfers 🙂

To be clear, nowadays we have our Soil Scouts, Delta T’s and the like to measure soil moisture but I’d always add the caveat that it is the top 25mm that dries out quickest at this time of year so be careful you’re aren’t taking readings under the depth that matters. I’d also add that the top 25mm is where the majority of your organic matter is so once this has dried out, it is a pain to rewet. I’m not saying go out and lash water on, more that you need to keep a very good eye on surfaces this week, look for the tell tale wilting / footprinting and act accordingly.

OK that’s me done, all the best for the coming week.

Mark Hunt