April 27th

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Hi All,

Well as we nudge towards May we’re still experiencing a prolonged period of cool weather and I’m afraid the outlook longer-term into the beginning of May doesn’t look particularly promising. The cause is our old friend the jet stream and this year it is sitting much lower than normal for the end of April. In fact in the 10 years that I’ve been watching the weather closely, I’ve never seen it sitting this far south, this late in the year.

Usually by now warm air has started to push up from the equator and move the jet stream further north, allowing temperatures to rise in Northern Europe, but not this year. As you can see below, the projected path of the jet stream for the 7th May is still low with a capital ‘L’ and that means cool conditions are the order of the day for the time-being I’m afraid.

It’s not all doom and gloom though from a grass growth perspective because there is a change on the way on that front 🙂

jetstream070515

So with that in mind how is this week panning out ? I know some of you got the promised rain at the weekend, some of us got a little and some none at all, so do we have any more on the way ?

General Weather Situation

Ok for Monday we have a bright start for most of the U.K and Ireland after yet another cold night with a widespread ground frost. Through the mid-morning we have a band of rain, sleet and snow (for higher ground) moving into the west of Ireland and across country. By early afternoon, the band of wintry showers is into western Scotland and the north-west of England and I bet it’ll leave Goatfell on Arran looking like a Christmas Pudding 🙂 Further south and east, It’ll be a lovely bright sunny day, warm in the sun, with that wind set in the north initially and due to swing round during the day. By the evening that rain will be into west Wales, but will fizzle out as it moves eastwards leaving a band of wintry showers affecting an area from Manchester north up to Scotland through the night. Temperatures will nudge double figures, maybe a tad higher in The Smoke down south.

For Tuesday those wintry showers are still in situ over north west England and Scotland with the areas south and east of this dry and bright after another overnight frost. Ireland looks to have a better morning on Tuesday though there’s likely to be some wintry showers affecting Sligo and Donegal I think. By late morning / early afternoon, a more concentrated band of rain pushes into western Ireland and Scotland, again falling as sleet and snow on higher ground. So a wet 2nd half of the day for Ireland and Scotland and perhaps some of that rain pushing into West Wales again late in the day. Further south it’ll be a dry, bright and cooler day even in the sunshine with temperatures struggling into double figures despite the wind being westerly. It will be windy on Tuesday as well and that’ll keep the temperatures down.

Moving into Wednesday after possibly a frost-free night, we have that rain over Ireland pushing eastwards into Wales and the north west of England in the early hours and moving eastwards as we approach the morning rush hour. By mid-morning it will have cleared Ireland and Wales and stretches in a narrow line from the south-west of England up to The Humber. Scotland looks to have a mixture of sunshine and wintry showers for the morning, with showers moving into Ireland as well later in the morning. By the afternoon on Wednesday this rain is moving along the south coast in a line up to The Wash and pushing eastwards finally making the south-east of England by mid-afternoon. Temperatures still nothing to shout about, high single figures and low double figures for most despite the westerly wind which will be moderate to fresh. Later into the evening we will see those showers from Ireland push eastwards across Scotland and the rest of the U.K.

For Thursday we have a band of rain pushing over Ireland early doors and moving eastwards into Wales and the south-west of England for the rush hour. This rain is set to consolidate and move eastwards through the morning in a line from the south coast up to Leeds / Manchester way. For a change Ireland and Scotland look to have a lovely day, lot’s of sunshine for sure. This rain slowly crosses the southern part of England through Thursday afternoon and finally clears by the end of the day. Temperatures remain on the cool side and in that rain are unlikely to hit double figures, that’s low for the end of April in anyone’s books.

Closing out the week we have a dry bright start projected across all of the U.K and Ireland with the chance of another ground frost. By late morning a band of wintry showers pushes into the northern Highlands and the Black Isle and moves south into The Borders and the north of England by late afternoon. These showers then push east and move off into The North Sea by the end of Friday. Temperatures will be similar to the rest of the week, high single figures and the wind will swing round to the north and then east during the day. Further south it’ll start to feel milder.

The Bank Holiday weekend is looking to start dry, bright and chilly for all, but during Saturday morning it looks like we have some pretty concentrated rain pushing into Kerry and crossing Ireland during the day. This rain looks heavy for Mayo, Sligo and Donegal. Elsewhere it looks dry and feeling milder in hazy sunshine with the risk of showers pushing across the U.K later on Saturday. Sunday is a tricky call because there’s a band of rain projected to affect a narrow line stretching from the east coast of Ireland across to The Humber. South and north of this it looks set to be another largely dry and sunny day and it’ll feel a little milder as well with temperatures nudging into the low teens as the wind swings round to the south west. That said, I expect some of those showers to be wintry in nature across The Midlands and north of England through the afternoon. There’s also the possibility of more rain further south on Sunday so it’s changeable outlook for sure. Monday is looking a bit like a re-run of Saturday with rain pushing into Kerry and tracking across Ireland through the day. Elsewhere we are dry, bright and again a little milder for Monday, with night temperatures picking up, but always the chance of a shower through the day.

Weather Outlook

It’s an interesting one meteorologically-speaking next week because we have an Atlantic low in charge so that means south-west winds, changeable, kind of ‘April Showers’ weather for the start of May. Although it won’t be warm, it should be mild and I think next week’s weather if it transpires will be a significant game changer from a grass growth perspective.

Why ? because it’ll be mild and I think we will move away from this ‘growth handbrake’ caused by low night temperatures. So I think we will have milder nights next week, showery on Monday, clearing then to be dry and mild with moderate south-westerly winds. Mid-week, next week I expect some more showery weather to move over the U.K and Ireland, pushed along by those south-westerly / westerly winds and clear for Thursday. Friday looks set to be a quieter day as we enter a brief hiatus but we will still have the risk of rain before another deep Atlantic low is set to come our way next weekend possibly. It’s a pretty deep low so that means windy and potentially pretty wet.

Agronomic Notes

As intimated above although we have a pretty cold week coming up I reckon there’s a fundamental change in the weather on the way and that will hopefully make life easier for everyone maintaining grass for a living, looking on the bright side :). This is particularly the case for those people who are chasing growth and recovery be it from winter wear and tear, aeration, etc.

I’ve charted out the projected minimum and maximum temperatures for the next 10 days or so to highlight how the arrival of a westerly airstream and milder air will make a change to our growth prospects.

27040805gddcOMP

So that means we should see minimal growth this week on all areas even outfield, though with the arrival of rain for some over last weekend, this will kick in growth of Poa annua var. reptans (Perennial Poa),. Up until now this species has been sitting back and doing very little. So although growth rates will be nothing to shout about, we should see more uniformity in the grass sward going forward.

From the end of the week the combination of rainfall for most places and milder night temperatures pushing into next week will see a continuation of this growth pattern and I think with at least another low on the way behind next week’s one, the pattern will be set for the time-being (Provided of course the weather plays ball that is)

Poa annua seedheads

Poaseeding2April1st2014

With Poa annua var. annua seeding now on higher height of cut outfield areas and the clean up strip / thinner areas on fine turf,  I think we will slowly see the perennial form joining the party through next week, kicked off with the combination of milder night temperatures and rainfall. I don’t think it’ll be a massive flush of seedheads because we’re not projected to see really high temperatures, just a gradual increase in visible seeding I think as we go through the week.This will continue as we go into May.

Disease Activity

There’s a chance with the increase in night temperatures and more prolonged leaf wetness that the unsettled outlook brings that we will see some Microdochium nivale activity. That said though I’m hoping that with better growth rates we will be able to keep pace with this without having to resort to a fungicidal application. Fingers-crossed there because I think the drier start to the year experienced by some of the U.K and Ireland has kept this pathogen’s activity at bay…which is nice. Other than Microdochium I don’t think we have too much to worry about, maybe a  little in the way of Fairy Ring likely to show it’s head as well as the humidity increases, no great shakes there though.

PGR Usage

With the cool start to the year and the projected uplift I think we should start to look at applying TE. Now I know there’s lot’s of discussion on the various forums and websites concerning rates and frequency, with some end-user’s already applying PGR, but for me I just don’t see the point. I’m not sure it’s going to do any harm, but let’s face it the TE molecule itself isn’t being broken down quickly because temperatures are low, the rate of grass growth is slow, regulated by it’s own PGR (The Weather…)

In some cases people require growth whether it’s on outfield turf to recover from winter play on sports pitches or tees for example, that have been battered through the winter, overseeded and dressed and now need to build coverage before the summer. On greens if you’ve aerated, you need growth to get those holes filled in, you need growth through topdressing in order to keep a nice surface, why regulate now if this is the ballpark you’re in ?

One other thought, if we’re regulating the grass plant for most of the year, isn’t that going to play into the hands of other competitive plant species like Silver Thread Moss in terms of reducing the competitive advantage of grass vs. moss ? You’d have thought this would be the case particularly when light levels are low.

I’m a fan of PGR’s for sure, but it’s horses for courses and no one size hat fits all. My advice is look at your own situation, where your growth is, where you want it to be and cut your cloth to suit accordingly. (I now claim the prize for squeezing as many Idioms into one paragraph on turf!!!)

Ok off the soapbox and onto the in tray !

All the best…

Mark Hunt

 

 

 

 

 

 

 

 

6 thoughts on “April 27th

  1. Mark jones

    Thanks Mark,
    Any growth would be helpful in North Manchester.
    We’ve had everything this week, weather wise. Certainly, way off PGR use up here.
    Keep up the good work.
    Mark Jones, Manchester GC.

    PS Looking forward to Jerez this weekend.

    Reply
    1. mark.hunt Post author

      Hi Mark,

      Looks like the weather is going to play ball growth-wise, with the milder nights and rainfall both making an appearance, though I doubt in Manchester you’re short of the latter. Thanks for the feedback and Jerez should be cracking, Danny, Sam and Cal are well placed but of course being in Spain, the Spaniards will go for it !!!

      Mark

      Reply
  2. Dave Berry

    Hi Mark. I really find your information useful . I recently sprayed for Leather Jackets and the Larvae were jumping out of the sward with tummies full of my roots . Colour & Growth has since improved , may be worth mentioning that to the guys out there struggling for some early season pick up .
    Keep up the Great work .

    Cheers.. Db

    Reply
    1. mark.hunt Post author

      Hi Dave,

      Cheers for the feedback and a great reminder about Leatherjackets.

      I noticed some 7-10 days ago and you’re right of course, these guys can be a real pain in terms of slow recovery, especially if people have aerated and they’re chewing around the core holes at night to give that countersunk effect. Often the only time you really know that they’re causing an issue is when you spray and then monitor growth, clipping yield and colour and see an uplift.

      Thanks again for posting a comment.

      Mark

      Reply
    1. mark.hunt Post author

      Hi Michael.

      Growth-Degree-Days (GDD) is a measure of the growth potential of a plant and is calculated from an average of the maximum and minimum temperatures in a day.
      The formula uses a base temperature, in my case I use 6C and this is subtracted from the average day temperature to give a figure known as a growth degree day.
      The higher the GDD figure, the more potential there is for the plant to grow. It’s a crude, but effective measurement to quantify growth potential and I’ve found it really good to compare climatic data year on year. So for example if we have a cool spring like this one, exactly how different is it to the same day last year in terms of growth ? Well GDD models can help you quantify this difference. Originally it was developed in the States to try and predict when Poa annua started seeding so they could apply a PGR, or Plant-Growth Regulator. (the second part of your question) A PGR is a material that alters the growth characteristic of a plant, in some cases this can be to reduce upright growth (As trinexapac-ethyl does) or prevents the plant from seeding (As Ethephon does). You can find both GDD and PGR examples in the link here.

      Mark

      Reply

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