There is an old English proverb dating back to the 1700’s that states “Never Cast A Clout Until May Is Out”. A Clout was an item of clothing and although there is some dispute on the meaning of the term ‘May’ as some take this to mean the old English name for the Hawthorn (May Blossom) and some the month of May, the gist is…. Don’t discard your winter cloths till we’ve seen the back of May.
Well this couldn’t be more true for this year because May will finish up being a cool month, courtesy of a trough in the jet stream (for the 2nd year in a row) and it was wet at times as well.
So how are we looking for the coming week and beyond ?
General Weather Situation
Tuesday looks to be a dry and settled day for many with only a hint of some light rain drifting into north-west Scotland later in the morning. There will be plenty of cloud cover but it’ll break from the west through the morning, so Ireland, the south-west of England and later central England and The Midlands look to see plenty of sunshine. That cloud cover may linger on eastern coasts and over The Borders and Scotland. In that sunshine temperatures will push up to mid to high teens in a moderate north-westerly wind.
Into Wednesday and we have another dry and settled day for many but with more cloud cover for most areas. This cloud cover is courtesy of a weak rain front that will push into west Munster and north-west Scotland through the late morning and slowly move across Ireland through the afternoon / evening. Further south and east it looks a dullish day with little in the way of sunshine, maybe the odd break here and there. Temperatures will be a little down on Tuesday because of that cloud cover but still acceptable with mid-teens the order of the day. Winds will be light to moderate and will swing round to the west during the day.
For Thursday we have that rain front clearing Ireland and pushing into the western coastline of the U.K overnight, so the south west, Wales and north-west England along with Scotland will see rain for the morning rush hour. This rain will push inland through the course of the morning, but will fizzle out as it does so, so you may or may not catch a shower during the course of the day. By late afternoon most areas will be dry and the cloud cover will clear to give a nice evening. The exception looks to be north Wales, the north-west of England and Scotland where that rain may linger. Temperatures will be cooler as a northerly low begins to affect our weather, low to mid-teens for most and the wind light to moderate and from the north-west.
Closing out the week that low pressure system is set to rattle in plenty of showers across the U.K and Ireland, so starting off bright and sunny, but those showers will soon kick in. The wind will be from the west but because it originates from the north, Friday will feel much cooler with temperatures just into double figures. As skies clear at the end of Friday, temperatures will drop and it wouldn’t surprise me if there isn’t a ground frost in places by Saturday morning, (so cover up your Dahlia’s !), disappointing eh for the end of May ?
The weekend looks a tad tricky to forecast with I think Saturday likely to be cool, wet and windy for many. It looks to start ok, bright and sunny for many, but then a heavy band of rain is set to push into the south-west of England and track north and westwards through the day. Now at present this looks to affect only an area south of Manchester, but we will see closer to the time. Ireland looks to get rain as well, but not as heavy as the U.K and Scotland would stay dry and bright for Saturday. Sunday looks a better day after that rain clears the U.K during the early part of the day, but overnight rain will push into Donegal and later Scotland to give a wet outlook for Sunday with some of those showers falling as sleet over higher ground. Ireland looks to get the rain on Sunday and later this rain will push into the west of England and move eastwards overnight into Monday.
As we go into June is there any chance of the weather stabilising and heat building ? Well maybe because the projections show a shifting of the jet stream to a more northerly position. I’ve created an animating (above) which runs through the first 8 days of June and you can see how the path of the jet stream (shown in yellow, orange and red) changes.
Before this occurs though, we have a very deep Atlantic low pressure system to get rid of because that will dictate the weather for the very start of June I’m afraid. So Monday next week looks windy, cool and potentially wet, but more so for the north and west of Ireland and the U.K because that’s the path the low pressure system is taking. Further south it’ll be breezy but from Tuesday I expect it to warm up big time and temperatures will push up into the high teens and low twenties by the mid part / end of next week. The low pressure will drift off west (strange?) as that warm air pushes in from the continent so the north of Ireland and Scotland will pick up that warmth from Wednesday / Thursday onwards. By the end of next week high pressure looks to be firmly in control, so settled, warm and dry with south-easterly winds pushing that warm air up from the continent.
Next Monday is the 1st of June and it’ll be very interesting to look back at the first five months of this year and compare GDD stats because it’s been a rocky ride for sure in terms of growth and in particularly cool night temperatures. Before we do that though let’s look back at May so far and analyse why it’s been a characteristically tricky month for growing grass.
The first thing you can see is the up and down nature of both day and night temperatures with some cool nights right through till the current date. Now this isn’t anything unusual, it is typical May weather and I always say that until we get to the end of May, temperature profiles tend to look like the side profile of the Andes.
The up and down nature of the month has made life tricky though, both for managing grass growth on outfield and maintaining good surfaces on fine turf. I’ve charted out the corresponding growth potential profile for these temperatures and you can see how they map out. Take into account that a G.P of 1.0 is optimum grass growth and a G.P of less than 0.4 is a slow growth rate.
I tend to use Growth Potential from June onwards over GDD when looking at growth because it takes account of above optimum temperatures for grass growth in its formula whereas GDD does not. The advantage of this fact is that as we progress into summer (hopefully) we can highlight potential periods of plant stress and change our management styles accordingly.
You can see we have had 4 growth flushes and 5 growth checks through the month up until the 26th May.
The consequences of this type of growth profile for May
Over the U.K Bank Holiday weekend you can see we had the beginnings of a growth flush as the G.P rose on the 22nd, 23rd and 24th of May to near optimum levels for growth, so outfield areas have been growing strongly. This is particularly the case on un-irrigated areas because last week we also had rain for the start of the week so soil moisture levels were acceptable to carry this growth forward. Fortunately on the 25th we had a cool day and this has pegged back growth somewhat (with the cooler night temperature) so once these areas are back under control (and fortunately we have some dry cuts for the start of this week for most areas), they should stay that way this week because of the cooler outlook. (See the projected growth potential pattern on Meteoturf below, you can see how it is set to drop through the week)
Looking forward for outfield areas if we do get the rain at the end of the week and then the rise in temperatures next week I would expect a significant growth flush from the end of next week onwards so if you want to hold this back and extend viable presentation (because a slower growing plant uses less water) then once the low pressure moves through next week, that’s the time to do it with a PGR.
Fine turf has definitely had a rocky ride this spring because of the low growth potential earlier in the year, the extremely poor March and the cool and dry April. Skip forward to this week, we are still in the Poa seeding flush so surfaces are tending to look pale . This look has further been compounded by the cool night temperatures which have tended to drop the colour out of the grass plant. This will carry on through this week and into the early part of next week because of that cold air flow from the North Atlantic low pressure system.
On the plus side, if we pick up warmer temperatures next week this should move us QUICKLY towards the end of the seedhead flush, so the grass plant will start shifting carbohydrates back into the leaves (instead of the seed) and it’ll begin to green up and blend in with the other grass species present. For the time-being you could apply a drop of iron this week to keep things looking good but really I don’t think it will achieve much because we will lose colour again at the end of the week / over the weekend with the cold nights that are forecast.
Plant Pathogen Activity
Quite a bit of Microdochium nivale activity around last week because of the moisture and then the elevated temperatures as we closed out the week. As we go through some drier weather for the early part of this week, it should decline in activity but I expect it to kick in again next week after the projected rainfall and temperature increase.
An increase in temperatures in June will mean the start of Fairy Ring activity and if they rise as high as predicted then I also expect the first real plant stress (although we did experience some in April’s dry weather) so the symptoms of plant parasitic nematodes will become more prominent I’m afraid.
Loss of Chlorpyrifos
Last week (21st May) we had the sudden withdrawal of Chlorpyrifos insecticide, with an almost instant use up period. This has now been extended to the end of August in terms of using up any product you have in stock, but no product can be sold / supplied anymore. You can read and download a pdf copy of CRD’s latest statement here.
This is going to make life pretty tricky for us in terms of management of Leatherjackets as it was our only A.I for the job. I’m not sure what the future holds in terms of replacement products, I know there are quite a few new insecticide actives being introduced into the U.S market, but getting them through E.U legislation will be challenging for sure.
Since Chlorpyrifos is staying in agriculture (for the time-being anyway) I wonder if it’s worth someone (golf club, etc) applying for a SOLA (Specific Off-Label Approval) for managed-amenity turf on the basis that we have no other control for this pest ? It may be worth it, but until we know the rationale behind why the authorisation to use Chlorpyrifos disappeared so quickly, it’s unclear whether this approach would have any mileage in it.
This won’t be the last of the product withdrawals for our industry as I expect our fungicide options to narrow as well in the future with respect to Microdochium nivale management and then that will really make life interesting in terms of producing a clean, consistent playing surface from October through to April.