May 21st

Hi All,

Another Tuesday blog and unfortunately a premature publishing, so if you got a ‘blind update’ earlier, it was because my blog published just as I started writing it !, ho hum.

May is continuing its up and down weather pattern with North Sea ‘Haar’ exerting a big influence on the temperatures. Haar is a sea fog that drifts inland by convection and typically affects Scotland, the North of England and The Wash areas, but when the wind is in the north-east, it can push well inland. So last week we saw days like Thursday which were ‘Haar-free’ and the temperature shot up to 19°C, but the next day, the Haar moved in, bringing low cloud cover, upping the humidity and temperatures barely broke 12°C.

Speaking of last Thursday, I took a day off to fish Eyebrook reservoir, with my brother and dad to mark the 70th anniversary of the Dambusters raid in WWII. Eyebrook was one of the reservoirs they used to practice on for that famous night raid, flying at just 60ft above the water. So we sat there and witnessed a Lancaster bomber flying at 150ft right over our boat, twice, accompanied by 2 Spitfires and then later, there were 2 low passes by Tornado jetfighters, an absolutely fantastic experience, but it did put the Trout down 🙂

 General Weather Situation

Our weather is still subject to trough patterns as we saw last year, it’s just at the moment they are not lasting for long periods, but coming up we will be slipping into a trough and that’ll introduce cold air down from the north (see image right for Thursday’s temperatures), so not the best forecast for the coming bank holiday I’m afraid, but it shouldn’t be too bad Saturday and Sunday in the U.K.

Tuesday is looking the last day with reasonable temperatures, so after morning drizzle for some, the north of England and Midlands primarily, the outlook is reasonably dry with warm temperatures when and if the sun breaks through the low cloud cover, which may not be until late morning in those areas. Winds will be light / moderate and from the north. Overnight, the cloud cover thickens over all of the U.K and Ireland and this will be thick enough for some light rain coming into Wednesday, which is the change day as that cold air moves into Scotland early in the morning and pushes down, so you’ll notice the colder start to the day up there. Further south, not a bad day, temperatures dropping a little into the low-mid teens and again, a chance of some rain, later in the day, down a central belt of the UK, stretching from the north of England to The Midlands. By Thursday, that cold air has pushed down across the U.K and most of Ireland, so the morning starts cold, with fresh northerly / north-westerly winds and a much chillier feel to the weather in general. The cold air will push rain into Scotland early doors and I expect this to fall as snow over the higher ground, it’ll be that chilly 🙁  That rain will push south across most of the U.K through Thursday morning, but won’t reach the eastern coast of Ireland till the afternoon, so Connacht and Munster should miss most of it. Friday looks a drier, sunnier day, but chilly, with a north-east wind pushing cloud cover off the sea, though there should be some sunny intervals as well. There’s a chance of light rain down the westerly coasts of England and Wales and also potentially heavier rain coming over from the continent for the south-east of England, but as we saw last weekend, rain from the continent is not the most reliable to forecast, one minute its there, the next it isn’t. The bank holiday weekend isn’t looking too bad as the coldest part of the trough pushes away from the U.K, so Saturday and Sunday are looking warmer, we’re talking low-mid-teens, instead of barely double figures prior to that. Saturday looks dry and pleasant with slightly lighter, north winds and hazy sunshine. Overnight into Sunday,  a rain front pushes into west Connacht and Munster and moves eastwards, so a potentially wet day for Ireland on Sunday, but rainfall amounts won’t be heavy. This light rain will push eastwards into Wales and western England introducing more cloud cover later in the day, but further east it’ll be similar to Saturday, so sunny, with cloud cover and temperature’s in the low / mid-teens. Later in the day, there is a threat of rain pushing over from the continent, but as mentioned earlier, this is a tricky one to forecast, so best keep a close eye on your Headland Weathercheck portal for a more accurate forecast closer to the time.

 Weather Outlook

If this rain does push over from the continent later on Sunday, then Monday looks to be unsettled, with showers, especially across the east side of the U.K and a cooler wind to boot, from the east. Further west, the outlook is better, with temperatures picking up a little for the west of the U.K and Ireland, but still with a risk of showers. Looking into next week, I think the outlook is unsettled, with more rain and we’ll be keeping an easterly / then northerly wind direction, so temperatures are likely to be mid-teens at best. Later in the week, high pressure is trying to assert itself, so hopefully warmer and drier for the 2nd part of the week.

Agronomic Notes

Disease Pressure

When you look at this pic from my weather station, taken at 10.21 p.m. last night, it’s not difficult to see why disease has become very aggressive over the last 3-5 days. A temperature of 16.1°C and humidity of 83% is ideal for the rapid development of Fusarium,  I’m getting (and observing) lots of reports of disease outbreaks, so if you think you’re the only one, you’re not. The question is to spray or not to spray and for me that depends on 2 main factors ;

1. – The Poa content of your greens – If it’s high, like most people’s, then the disease threat is also high and …

2. – Looking at the outlook, it’s primarily cool, so the chances of growing it out are not as high as usual for this time of year, particularly as we’re going to get a run of cold nights, so that’ll drop soil temperatures and hence growth potential.

I’m not a fan of spraying indiscriminately through the growing season, (I’ll leave that to the big chemical companies), but taking into consideration the above, I do think the best policy is to spray, either with a light rate contact (Iprodione) mixed with iron or a systemic along the same lines, provided the latter is a good one for controlling Fusarium, so in other words, not a Strobilurin chemistry.

 Nutrition and Growth Potential

If you look at the daily GDD data below, you can see from the profile that it’s up and down like a side profile of The Alps. When we get warm nights, we get a high GDD, when we get colder nights, a low GDD, so that’s what grass growth is like at the moment, up and down, particularly for Poa annua, because it’s putting it’s energies into seed head development currently. Interpreting the GDD data into actual growth levels, i.e clipping yield is the next step for me, to make this data more meaningful, but gut feeling is that you need a GDD figure over 6 to give good growth and you can see we’ve had very little of that over the last 7 weeks.

This growth pattern is quite normal for May in my experience and it’s not usually till the end of this month that soil and night temperatures stabilise and growth patterns become more constant. The problem is every time we get a cold weather trough pushing down, it knocks back growth, great for keeping outfields under control, not great for producing consistent greens.

Nutrition

Two choices here – either stay with low temperature-available granular products or apply low temperature-available foliars, but remember with the latter that these will be less effective if the plant is checked prior to application and / or you get high levels of rainfall just after applying. So if you’re using liquids, I’d tighten the spray frequency down to 14 days maximum, don’t try and stretch things out because it won’t work when we have this type of weather.

Maintaining Uniformity

In my experience Poa isn’t growing consistently at the moment, whereas bentgrass is, so keeping uniformity on a greens surface is challenging. As I’ve said in earlier blogs, a tight cutting height definitely helps to achieve this, certainly <4mm. I know cutting height is a great subject for debate :), but the fact remains, that a lower cut surface provides less chance for the different physical characteristics of the grass species present in your greens to manifest themselves, so that means less bobbling. The plant is not under stress from environmental pressures (heat, drought, etc), but it is seeding, so we have to be mindful of this. Applying Trinexapac-ethyl to greens surfaces is still too early for me, but as always I have an open mind on this, so if anyone’s thinks that they’ve achieved a better surface by applying an early PGR, drop me a line / comment on this blog and I’ll pass on your experience. Outfield turf like tees, approaches, sports fields is another matter, the height of cut is higher, the grass species often different and here applying a PGR makes sense to me at the moment.

Rolling can be also be a good ally during these conditions, just to improve ball roll and take out the bobbling aspect, but you need a firm, (topdressed incorporated / well-integrated into the surface organic matter) surface to get the best out of it. Of course topdressing can help as well, but the tricky part here is that when growth levels are low, it is sometimes difficult to incorporate a good quality, coarse-medium dressing into the surface, without removing it all and compromising the condition of the cutting blade.

So it’s a balancing act, for me, light inputs, applied frequently are the way to go to maintain consistency, so that’s light dressings, light brushing, a tight cutting height and nutrition along the lines I’ve detailed above.

That’s all for now, sorry for the cock-up publishing earlier and I’ll try and get back to my Monday slot in future, but of course next week is a bank holiday here, so we’ll see.

Mark Hunt

 

6 thoughts on “May 21st

  1. Greg Evans

    Mark, I must admit that I was falling asleep until I read ‘maintaining uniformity’ and then you mention the magic words, ‘cutting height’ and bang I was awake:) I have two comments on that paragraph. The first is on a tight HOC, especially at this time of year when the poa is pretty ‘sleepy’ and bent growing. If you are at 3 let alone 4mm, your surfaces must be pretty bumpy! Second is on trinexapac-ethyl. As you know I’m a big fan of this and tomorrow we will be putting on our 5th application this spring. I disagree that it is too earlier and would advise anyone with a poa dominated sward to get it on. Another good blog though!

    Reply
    1. mark.hunt Post author

      Hi Greg,

      I was smiling when I was writing that paragraph as I know your thoughts on both cutting height and PGR’s and thought I’d get a reaction.
      With respect to Poa being sleepy, it seems to me that the only time Poa isn’t sleepy nowadays is between September and March, and from April to August our mixed bag of wayward weather doesn’t suit. I think the best approach would be to organise some field research, but unfortunately geographically we’re pretty limited in the U.K for independent research facilities in the south of England, where the climate is more temperate. Fair play for thinking out of the box and try reading the blog again if you want a good nights sleep 🙂

      Mark

      Reply
    2. aj

      Greg Evans

      5th application hmmm, just wondering whats ur application rates on trinexapac-ethyl, and how often ur going.

      Reply
      1. Greg evans

        200ml and today have gone at 400ml for our 6th app. I started the GDD on primo last year at set it at 200 but felt they tailed off. This year for our poa surfaces will be setting that figure at 150, which will probably mean weekly sprays all the way through.

        Reply
  2. Graham Pickin

    Thank you Mark for that very informative and helpful advice, what’s your thoughts on Phosphite as a blend with iprodione, some research says its very effective.
    Regards Graham

    Reply
    1. mark.hunt Post author

      Hi Graham,

      I think the concept of utilising phosphite with Iprodione makes a lot of sense to me because phosphites are held up to be truly systemic in their mode of action, whereas iprodione is limited to being a local penetrant, albeit a very good one in my experience. So in principle I’d see this tankmix as not only beneficial, but synergistic rather than antagonistic. The key is to ensure the phosphite is tank-mixable, not just with iprodione, but with other potential partners.

      Thanks for the feedback.

      Mark

      Reply

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