Phew !, what a scorcher the weekend was here in the sunny Midlands. Didn’t quite top out at the magic 30°C, but we got pretty close ! Congratulations to Scotland’s Andy Murray on his Wimbledon victory and to The British and Irish Lions as well, absolutely excellent, now all we need is for Cal Crutchlow (Coventry’s finest) to blitz Silverstone’s MotoGP at the end of August and summer will be complete in my books (from a sporting perspective of course)
As forecast last week, this week’s weather is set fair, dry and warm and no sooner than it has started, I know I’ll soon be getting questions “When is it going to rain?”. The assumption of many is that it’s been a cool, wet year up until now, but June was in fact a pretty dry month (especially compared to last year!), with rainfall varying from 27mm – Long Ashton, Bristol (Thanks James), 22mm -The Oxfordshire (Ta Sean) to 6mm, yes, that’s 6mm in the dry lands of Gravesend, Mid-Kent (Commiserations Lee). To put last year into perspective, Long Ashton recorded 188mm and The Oxfordshire,152mm, in 2012 ! Curiously I was thinking Ireland had been getting it all, as the bulk of June’s rain came from the west, but Met Éireann’s June rainfall data reveals differently, with Dublin running at 60mm (Airport), Shannon 64.2mm (Airport) and Belmullet, Co. Mayo down at 43.2mm, all low for Ireland. Even when it’s been cool, it’s been windy, so E.T rates actually ran reasonably high in June, with 76.7mm recorded at The Oxfordshire for the month. I also know we’ve already had some 4mm+ per day E.T rates for the start of July, so things are drying out big time, more of that later.
It’s that Jet Stream again….
As you can see from the schematic below showing how the weather systems played out at the back end of last week through to this week, the jet stream (the interface between the cool (blue) air and the warm (red)) has moved up north, in fact to be precise, over the last 10 days, it’s moved around 2,500 miles north, originally sitting down over The Med, till now it’s just south of Iceland ! The consequence is the warm air has pushed up and that’s what we’re experiencing now. Any sign of it moving back ?, err…no, not this week and most likely, not next week either…
General Weather Situation
This is going to be a pretty straight-forward forecast, as by and large, it’s going to dry, warm and sunny for most of the week, with precious little rain around and what’s more, a moderate north-easterly wind is going to ramp up those E.T rates during the day. A slight digression here, but on a personal note, as one who finds it very difficult to get a nights kip (too much whizzing around my head I think), at least the nights will be cool with that wind, so that should make everyone’s life easier 🙂
The temperature level isn’t consistent all week with things cooling down a little in the south mid-week, (though staying hot in the west and north) before ramping up again for the weekend in the south, with Saturday looking like it may compete for the hottest day of the year here. For Ireland, Scotland, and the north of England it looks like a weak weather system will come into play at the end of week, with a chance of rain pushing in Friday p.m to north-east Ireland and Scotland, moving south overnight with cloud cover into Ireland, the north of England and The Midlands for Saturday morning. Further south, any cloud will soon burn off, with a diminishing wind, to leave a very warm day indeed for Saturday and a chance of thunderstorms by late afternoon. Sunday looks hot and humid as well but maybe a few degrees down on Saturday.
So is it really going to last ?, yes I think so, at this stage I can’t really see much sign of change (right through to the last week of July), with an Atlantic high very much in charge through next week, so dry and warm, though I suspect temperatures won’t be quite as high as this week, or this coming weekend, more low twenties, than high twenties, with a little more cloud cover, but precious little rain , except for a chance over Scotland at the end of next week / weekend.
I’ve had a number of reports of Chafer Grubs swarming over the last couple of weeks, particularly in the west London M25 / M40 area and this doesn’t bode well for the future. You guys may already know this (but I didn’t), there are 2 main species of Chafers that cause issues on turf. They are easily confused, but their life cycles are very different and that’s important when you consider control. This one here is a Welsh Chafer and it’s recorded as having a life cycle from egg to maturing adult of 2 years, though I think this may vary. (as there is evidence of a 3 year life cycle). Read about the Welsh Chafer here as opposed to the Garden Chafer here. Anyone else noticed these guys recently ?
Continuing the monthly updates on this subject area, you can see that June this year sits fairly well with previous years, though it has to be remembered that neither June 2012, nor June 2011 were good growth months. Cumulatively you can see we have never really recovered from that cold, early start to 2013. The monthly totals are available to download here and the cumulative totals here. Thanks to Wendy for prepping these..
Coping with high E.T days….
I’ve talked about this before, but it’s worth repeating in these circumstances. Now some of you out there are using moisture meters, and by doing so, are able to monitor accurately the level of moisture across your greens, highlighting areas that need additional watering (hand watering) and areas that don’t. Not everyone is in the same fortunate position to accurately determine moisture requirements, so the next step is to replace moisture as a % of E.T loss, but again, unless you’re in possession of a good weather station, how do you know this ?, well you can buy a simple E.T vessel, which you fill up with water at the start of the day and then look at it early the next morning to determine how much water has evaporated. I work on replacing 60% of evaporated E.T loss to maintain good plant vigour, but of course there are plenty of variables that will alter this assumption, one of the main ones being turf maintained in shade. Turf in shade does not have as high an E.T loss, normally due to lack of air flow (less air flow = less evaporation), so the irrigation requirement on shady greens will normally be lower..How much lower ?, well a class I did at this years GCSAA show in San Diego suggested you should work on 50% of the irrigation requirement for a green in shade vs. one in the open. Of course this also applies to those of you maintaining pitches in stadia situations, where the balance between E.T loss, irrigation and humidity is critical. So a rough calculation, is that a hot, dry, windy day will have an E.T of 4.0 – 4.5mm, so using the 60% replacement rule, that means you should be applying 2.4 – 2.7mm of water by irrigation to keep things ticking. Irrigation on turf is at present an in-exact science and one where use of a moisture meter can help you to really understand how your greens behave irrigation-wise, budget-allowing 🙂
Aside from irrigation, the other general markers are to keep growth rates low with light, foliar feeds and obviously PGR’s. I’d hasten to add that this doesn’t mean that you produce a nutrient-deficient grass on the back of this because there’s at least two or three nutrient-deficient summer diseases that you’ll play right into their hands of if you do, namely Dollar Spot (1st UK report today), Anthracnose (bits doing the rounds) and Red Thread (plenty in last weeks humidity). So keeping things balanced is the name of the game during conditions like these and I’d always be maximising my biostimulant usage prior to and during this type of weather, either applied in conjunction with your foliars or with your wetting agent (I prefer the latter)
It goes without saying, but of course I’ll say it, keep cultural work to a minimum, especially in terms of lateral aeration like verticutting, scarifying and Gradening and if you do have to do them, make sure you maximise soil moisture levels in order to get recovery.
Taking about shade earlier, I noticed something this weekend, maybe a coincidence, maybe not. I sprayed 2 areas, approximately 5 weeks ago with a market-leading, tank mix (:)) of slow release, water-soluble fertiliser, liquid iron (non-staining) and a PGR. (no product names because this blog is never going to be product-based one, lol)
One area was in shade and according to a DLI meter receiving 60% of the light of the more open aspect, 2nd site. Well the area in shade is no longer under growth regulation and is actually flushing, whereas the more open aspect site is definitely still under regulation. Now it could be nothing, but a grass grown in shade is known to grow differently to one in the open, and one of the key differences is the fact that grass in shade grows up towards light and therefore has a tendency to elongate more, with more distance between the nodes. Perhaps it produces more gibberellic acid in order to achieve this ? (as GA is the hormone that promotes cell elongation), so rate for rate, needs more PGR to regulate it ?. Now you can easily produce the counter-argument that grass in shade grows less because of lower light availability limiting photosynthesis, but maybe we’re confusing growth potential with an aspect of that growth, i.e elongation, maybe it grows less, but the growth it does produce is more elongated ?. I’d be interested if anyone has noticed a difference in the performance of PGR’s applied at the same time / rate to grass in a shady or low light situation vs. a more open site ?
I’ll leave you with that poser, time to crack on….