September 18th, 2023

Hi All,

Well I am back from my travels to the beautiful Lyn peninsular in North Wales, full of Bara Brith. That area of Wales is truly a gem and for me it is genuinely lovely to hear the Welsh language in full flow. I also love to go to sleep and wake up to the sound of the sea. There is something about having a connection with the sea, to the sound of waves breaking and its latent power. Even the Blackberries I picked alongside Pwllheli Golf Club tasted slightly seaweedy :)

Of course I did some fly fishing in the sea and managed to catch some small Bass and Pollock which was great. At night I tried some lure fishing and was astounded to catch what I thought was a lump of Wrack (seaweed) initially. As I pulled it from the waves and flicked on my headtorch I was greeted by a the strangest sight as a Squid had looped a tentacle around the lure. It wasn't hooked, harmed in any way, but equally it wasn't happy and squirted some ink my way for good measure. Freaky, maybe too many Captain Nemo movies for me I think as I hastily grabbed the forceps, un-looped its tentacle and of it went. 5 minutes later, I watched a much bigger squid come right up to the shoreline underneath my feet, snaffle something and swim off powerfully. I called it a night....freaky or what. I didn't think Squid were living along the North Welsh coast but apparently they are on the increase !

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Turning on my pc this morning I was slightly surprised to see some significant rainfall totals dotted across the U.K due to some heavy thunderstorms that crossed from south to north overnight. The ATD Lightning network recorded over 18,000 strikes in a 24-hour period.

Currently (08:20am) the rain (shown on the Netweather.tv V8 radar) is heading north and east, with some particularly heavy rainfall totals for Wales, The South West, Lincolnshire and Yorkshire.

One of our Davis Vantage Pro weather stations recorded 53mm falling in a 24-hour period. In actuality, that rainfall fell over 4 hours this morning with 25mm recorded in one hour. The rainfall rate peaked at 111.8mm per hour at 05:45am, that's 4 1/2 inches an hour in old money. Autumn has definitely arrived early this year....or has it ?

GIF's courtesy of tropicaltidbits.com

General Weather Situation

For the first part of this week's weather, we will have low pressure in charge. This will be characterised by some very strong south westerly winds and rainfall moving south west to north east across the country. Not great news as that'll mean a lot of leaves on the ground, which is early I think this year. So bands of heavy rain which will cross Ireland into the west and then head east and north accompanied by strong winds will characterise the first part of the week. I think most areas will see some heavy rain during this period but Tuesday overnight into Wednesday's rain looks potentially the heaviest, finishing off with significant rainfall totals across the south and east of England overnight into Thursday.

For today we have a band of rain moving eastwards and another pushing up from the south coast into East Anglia later in the day. It will still be humid ahead of the rain but behind it, much fresher and cooler as Ireland have already experienced after a day of rain yesterday and the arrival of much cooler weather over the weekend. This cooler air will affect western and northern areas of the U.K initially before covering all of the U.K by weekend with the threat of frost in The Highlands. That isn't early. As a nipper I remember fishing Dulnain Bridge, Scotland in a grass frost on the last day of August !.

So 14-19°C will be the temperature spread, with the cooler air west and north.

Tuesday sees more rain cross Ireland overnight into Wales and the west coast of the U.K by the morning before moving inland. This rain front currently looks to vector northwards during Tuesday and bring heavy rain to The North West and west of Scotland later in the day with a more showery outlook for England. It will be very windy though. As the low pressure spins around it'll bring more rain to Ireland on Tuesday evening, initially to the north and north west but this will push south and east overnight bringing heavy rain for Kerry and West Cork potentially. By Wednesday morning, this rain will be across The Irish Sea and into The North West and North Wales moving down into South Wales by lunchtime and then tracking eastwards across England and finally pushing down into East Anglia and The South East later in the day. Again very windy with a similar temperature range.

Thursday will be a quieter day and drier for many but they'll still be plenty of rain affecting The South West and western-facing coasts. Lighter winds from the south and south east but it'll feel cooler than of late across England and Wales. Some showers across the north and north west of Ireland as well. Drier inland though. Later in the day the nearby low will push more rain into Scotland and down the north west coastline into northern England. Closing the week we have a showery outlook for Friday and with a northerly wind now being pulled down by the trailing edge of the low pressure, it'll feel proper chilly with 14°C likely across many areas.

The outlook for the weekend is decidedly mixed with Saturday looking like the driest day for the U.K & Ireland before a band of rain pushes into the south west of Ireland on Saturday early evening and this then crosses Ireland overnight into the west of the U.K on Sunday. So Sunday looks wetter, certainly across the west and it'll be windier with that wind swinging round to the south west again. This will also mean it'll feel milder with temperatures pushing up into the high teens for the day across Ireland, Wales and England, with Scotland sitting 2-3°C lower.

Weather Outlook

So the GIF above is how we are projected to start next week and it is clear to see there is a north-south divide when it comes to temperature, with warmer, more humid air across the south and cooler, wetter air across the north. The isobars are packed quite tightly so it means the breezy theme will continue at the start of the week, however the theme for the week thereafter is looking decidedly more settled with a high pressure peak pushing up. So next week could see a return to high pressure, warmth and settled conditions with temperatures maybe in the low twenties.

Now as usual my outlooks are heavily caveat-laden but the signal is growing for a warm, dry settled period building next week and lasting potentially till next weekend. Watch this space.....

Agronomic Notes

I can't recall a year when I have received so many pictures of Dollar Spot disease from across the U.K and Ireland.

Alongside Dollar Spot, I could add Red Thread, Waitea Patch, Superficial Fairy Ring, Anthracnose Foliar Blight, Microdochium and plant parasitic nematodes to that list.

And we are only just over half-way through September !!!!!

What a summer for disease pressure !

Without a doubt it has been one of the more challenging years for disease management courtesy of the wetter, cooler and as a consequence, much more humid July, August and now September. Throw in some high stress periods in May, June and September and you have the perfect storm for a groundsman / greenkeeper to try and deal with, whilst keeping management and members alike 'happy'.....

If you look at the Smith Kerns Dollar Spot Probability Model, in the States they use a probability threshold of 20% to suggest that above that there is a risk of Dollar Spot. Now it doesn't just relate to this disease and for me I have seen clear associations with this the Smith Kerns model and Microdochium, Red Thread, Leaf Spot and the like.

OK, it is 'hampered' by the fact that the temperature range for this model is set between 10-35°C and this doesn't work for some of our cooler temperature diseases, notably Microdochium, once we get deeper into the winter. That said, it is a really useful tool and the fact it is free to use is something we should be grateful for. I have pasted the link before to the model but it is here for your reference.

So If we look at the chart below which shows Smith Kerns Dollar Spot Probability (SKDSP) from 01-05-23 - 17-09-23 using data from a Davis Vantage Pro weather station located near Sevenoaks, Kent. I have drawn the line at 20% to represent the threshold used in The States.

You can see a clear succession of peaks throughout the year.

This started when we had an unusually wet April and beginning of May associated with high humidity and increasing temperature. That was peak 1. Thereafter we entered a very hot and very dry period as a high pressure associated heat plume pulled up hot and dry air from southern Europe. The SKDSP dropped back because the air was dry, the humidity was low and disease pressure due to less periods of plant leaf wetness, correspondingly low.

Around the 12th of June, the weather began to break, humidity rose ahead of a wave of Atlantic low pressure systems and so did the Smith Kerns. I have graphed out rainfall below on the same timescale and you can see how regular amounts of rain maintained a higher atmospheric humidity and corresponding Smith Kerns peaks throughout the summer providing an additional 6 peaks of disease activity.

Then we come to the beginning of September and that high pressure heat plume that we endured / enjoyed recently depending on your perspective. No rainfall associated with this of course but rather than pulling up hot, dry air as we saw in May, this weather event pulled up very humid air. So no rain, but lots of humidity, lots of dew, warm overnight temperatures and a perfect breeding ground for fungal disease.

This culminated in a peak SKDSP level of > 50% on the 10th September.

So if you are looking at a whole bunch of disease recently, it was this last peak that did the bulk of the damage. That in short is a diary of this year from May and hopefully explains that we have had a concerted amount of disease pressure this summer AND that the cooler, wetter weather was behind most of the disease pressure peaks, BUT crucially, not all of them. As we progress towards the autumn, it is these peaks of warm, humid air that are behind the bulk of our disease damage on golf courses, sports pitches and bowling greens alike. These are the things we need to look out for and indeed we have a potential warm air spike next week on the GFS outlook.

Will it be a warm, humid air spike ? Possibly.......

More growth, more topdressing ?

One of the other headaches this year (in a way) has been growth levels. With warm, wet weather we haven't had a traditional period of dry, dormant growth since the May-June period earlier in the year. Now don't get me wrong, I would choose a cooler, wetter summer over a dry scorcher as southern Europe has endured with temperatures in the 40's, but that's just me. They both have baggage from a turfgrass management perspective.

So having non-stop growth has meant more cutting, more diesel and electric usage (depending on your machinery of course) in terms of outfield areas but also keeping green speed up has been a challenge. For sure if ever a year was a dead cert for plant growth regulator usage, it was this one, however with some of the peaks in growth, even using a PGR didn't ensure good green speed.

Below is a graph of daily Growth Potential (G.P) from the same Sevenoaks location as above over the same time period. Remember when relating to G.P, 0 represents no growth and 1.0, optimum growth.

I have set the threshold level at 0.9 to represent very high growth levels that would mean consistent cutting required on managed-outfield areas and the potential for slower green speed despite PGR usage, rolling, etc. As with the disease graph you can see a succession of peak growth events throughout this year since May.

More growth means more organic matter production

One of the significant things that this graph shouts out to me concerns organic matter production. These long periods of high growth rates will be generating a lot of organic matter and that means a higher than 'normal' requirement for topdressing.

I remember spending some seriously quality time with the late, great Dr James Beard when we were travelling together on a turf road show. At each venue, Dr Beard would take a hole changer and remove a profile from the greens and then talk through what he could see, what it told him and how he would advise addressing any particular issues. During one of these sessions, a superintendent asked Dr Beard, "how much should I be topdressing annually ?", The first part of the answer was something like "Well you shouldn't be topdressing the same amount every year" because he maintained grass growth rates aren't ever the same year in, year out. In a higher growth rate year (more clip volume), there is a requirement for more topdressing (that is more frequent and more volume) to dilute the higher level of organic matter that is being created. The opposite applies of course as well. That is why measuring clip volume has in my mind some worthwhile justification even though I accept it isn't for everyone, time and resource-wise.

You see GDD and G.P figures are a reflection of air temperature, although granted the latter has a 'top out' optimum air temperature level above which the G.P levels will decrease because it is simply too hot. The last dip in September on the G.P graph above was due to above-optimum air temperature at the beginning of the month. So if we have a warm spell of weather but with no rain, the G.P will show very high levels regardless of the lack of moisture so it doesn't relate to a situation when growth will be limited by a lack of moisture rather than a lack of temperature. Measuring your clip volume is a great way of documenting actual growth levels and provides an additional benchmarking tool which can be used to understand significantly high growth levels and therefore a higher requirement to topdress.

So if you haven't been able to topdress more this year whether that be due to budget, resource, club policy, whatever, you can expect to have built more organic matter in the top 0-25mm. Sorry.

OK, that is me for this week, all the best.

Mark Hunt