Well the last 5 days have been a scorcher for many and coupled with high winds, (day and night) this has really ramped up the moisture loss with over 20mm combined E.T over this period (more on this later). Not only was it hot temperature-wise, but it was also very humid and as Karl from Meteoblue explained to me last week when I was over visiting, this makes the ‘feel-like’ temperature, 2-3°C higher than the actual because the body cannot cool itself efficiently by sweating. As I hinted last week, I didn’t expect this warm blast to be a prolonged one and sure enough there are clear signs of a breakdown as we go through the week, with some rain and much cooler temperatures from Thursday onwards.
General Weather Situation
Monday will start with a similar feel to the weekend, but with much lighter winds. Cloud will build over South-West Ireland and the South-East of England later in the afternoon and there’a risk of thunderstorms developing in a line from Kent up through The Midlands and the North of England. Kerry may also pick up some rain through the day, but amounts will be light. Tuesday sees noticeably more cloud cover with again the risk of some rain in the south-east and Mid-Wales particularly. Wednesday sees a band of rain moving up the east coast of Ireland during the morning and this will push into Wales and the west of England later in the day bringing showers to many places into the night. Overnight this band of rain consolidates and looks to give significant rain in the North of England, The Midlands and later in the south-east on Thursday, as the wind turns round to the north and temperatures really drop significantly. This swing will be most felt on the east side of the U.K, with the west comparatively sheltered. Friday starts off dull and cool with lots of cloud cover and those mid-20’s temperatures, a distant memory. as temperatures will struggle to reach half of that in a strong north wind. Saturday looks to start bright for most places, but a heavy swath of cloud will push down the east side of England and it’ll feel well-parky. The west and Ireland will be better with lighter clouds, but still feeling cool in the wind. Sunday maintains that east-west divide with the west feeling milder as those winds drop.
The start of the next week looks settled, with temperatures in the mid-teens, light winds and sunshine, but by mid-week, a deep Atlantic low is set to influence the weather with strong south-westerly winds and rain for many places affecting Ireland a day earlier.
Last week I talked about the need to button down the grass plant early in the week and after seeing the high E.T loss, I think that advice was pertinent. From Wednesday to Sunday last week, the E.T loss was measured at 20.9mmm at The Oxfordshire (ta Sean) and this did present some significant challenges in keeping rootzones damp. It’s clear from the events of last week and the weekend, that irrigation efficiency, E.T loss and player comprehension / feedback are not always happy bed fellows
In 2006, I was doing some wetting agent trials and not knowing a lot about irrigating to E.T loss, I starting off with an irrigation cycle that replaced 100% of E.T, the result was a very wet rootzone. I looked to the Internet for guidance and found a great paper by Clark Throssell entitled “IRRIGATION SCHEDULING FOR TURF SITES” in which he explained that total E.T loss needs to be adjusted by a crop correction factor (in this case, the crop is grass) to estimate the correct irrigation requirement. Of course there are lots of variables here, none the least, rootzone type, cutting height and obviously root development, because the deeper, more-branched a root system is, the more efficient the plant’s ability to uptake water. I experimented with this and found that a correction factor of 0.6 worked for me on my trials in providing healthy firm, Poa-Bent turf, without excessive moisture. That means that a weather station generated E.T of say 4mm needs to be multiplied by 0.6 to give a indication of irrigation requirement, in this case 2.4mm.
I do know some lads who run lower than this and as we know, an irrigation system will not provide consistent water across a green, so many greenkeepers use lower irrigation cycles and make the rest up with hand watering. All well and good, but deciding how much water a green needs by this process can be a bit hit and miss, though there’s a lot to be said for ‘feel’ and firmness using a knife to assess it. Last week I saw one of the newer moisture meters in action (thanks Peter and Glenn) and it gave some really interesting results across a green and importantly provided an assessment of which greens dried out quicker and where areas of the green require more or less hand-watering. Science has a place here to provide a consistent basis for monitoring irrigation efficiency and even more so when we are regulated by the water companies on irrigation use.
Enough about watering, if we do get cooler winds at the end of the week, it’ll knock the colour out of surfaces for awhile, but if the south-westerly low appears next week, it’ll soon rectify itself.
Disease-wise, all quiet at the moment, other than some very early Take-All, but it wouldn’t surprise me if we don’t have some oddities showing their head with the very high temperatures and humidity’s.
I’m away in the camper next week to sunny (ha ha), but hopefully breezy (big waves) St David’s in Wales and the following week I’m in France driving my Dad around so this blog may be a little disjointed for the next couple of weeks.
All the best