Hi All,

A shorter blog today because I’m meant to be on my hols, so bear with me on that front. Yesterday marked the Winter Solstice, so from today we begin the march towards spring 🙂 Outside it’s a mild 12.5°C, it might as well be early March from that perspective and already I can see the first signs that we’re turning the corner, with Hellebores just in the process of pushing out (what will be their flower heads) from under the soil. Looking at the coming week, we’re going to have an up and down ride with some colder, northerly fronts bringing wintry showers to some areas and some pretty windy, intense low pressure systems to boot.

General Weather Situation

So an abridged version today as I say, really just designed to give you a flavour for the coming week. For Monday and Tuesday we have a mild, westerly air flow in charge, so double figure temperatures and of course some rain showers, principally over Ireland and the north-west of England and Scotland, with other areas, south and east, staying dry. During Tuesday those showers will move northwards into western Scotland. Away from the rainfall, like the previous 2-3 days, you’ll have a drying wind, so that’s just what we need at present.

As we move into Wednesday, we lose that milder air, the winds remain westerly, but as skies clear, temperatures will drop in the north. That rain will push southwards overnight into Christmas Eve, so some rain overnight in the south, but it’ll soon move away to leave a dry picture over much of the U.K and Ireland, except for central Scotland where those showers will turn increasingly wintry in nature.

Onto Christmas Day and the wind swings round to the north, so a chilly, bright day in the west and north. Further south there’s some light rain and cloud cover to start the day, but this will slowly clear to leave a bright, but cold afternoon, with maybe a keen overnight frost.

Boxing Day sees the arrival of a rain front to Ireland and this will soon push eastwards on an westerly wind to give the north and Scotland a very wet second half of the day. Overnight that rain will affect most parts of the country I reckon and the wind will really ramp up.

By the time we reach Saturday, we have a potentially nasty, little northern low pressure in charge, so that means very wet and very windy, with those showers turning wintry over Scotland, the north of England and The Peak District, particularly in the 2nd part of the day. Those wintry showers could push further south later in the evening as the wind swings round to the north, so a cold end to Saturday.

Those northerly winds look set to remain through Christmas Sunday, but it’ll be a brighter, cold day with plenty of sunshine, though still with a risk of rain over western coasts.

Weather Outlook

After that low pressure moves away I think we are in for a spell of settled, high pressure, so lighter winds, cold, but crucially dry next week, with a risk of night frosts depending on cloud cover. Good weather for people to get out and just the thing we need to keep the disease pressure low.

Agronomic Notes

New GDD / Growth Potential 2015 Spreadsheet download it here

For 2015, we have a new spreadsheet already set up for you to enter your daily stats into. The chart has been updated over 2014, with the Growth Potential now working on an optimum temperature of 18°C, rather than 20°C. The reason for this is that I noticed during the hot conditions of July, the Growth Potential model didn’t show a reduction in growth during stress periods when the optimum was set at 20°C, but it did at 18°C. You can see how the 2 models work on the charts below for July, 2014. Micah Woods kindly commented that this was also the experience of other turf managers, so I’m not too far off the beaten track.


It is critical if we are to clearly identify the periods when the grass plant is under stress and manage these situations correctly. It is my contention that the Anthracnose activity that we saw in the summer and autumn of 2014 was intiated on or around the 20th / 21st July, even though the symptoms didn’t show for weeks afterwards. We can clearly see on the graphs above, a pronounced dip in the Growth Potential (@ 18°C) starting around this time and this was due to the combination of very hot days and warm nights.

The chart is also available in the menu at the side of the page, download it from wherever suits.


The USGA Green Section Record compile all of their articles released during 2014 in one place and some of them make great reading, so if you have 5 minutes to spare, have a look and see if there’s something down your street. The USGA Green Section Compendium of 2014 is available here


PGR’s in the summer – the debate goes on

On the subject of interesting articles, I read a really good one in Golfdom last week concerning the work that had been done on Trinexapac-ethyl usage during the warmer months of the summer. I know that end-users have fed back poorer efficacy with TE during the very hot periods of the summer and at least now we have part of the explanation why.

In the linked article it makes the assertion that the half-life (the point where a substance has decreased in concentration by 50%) of TE is significantly affected by increased temperatures and  therefore breaks down faster. It states that the half life of TE is 6.4 days at 17.7°C, but only 3.1 days at 30°C, so this means that the efficacy / longevity of applications of TE will be drastically reduced during hotter conditions. It also makes the point that applying higher rates during these conditions is a waste of time and ineffective. (BIGGA formum contributors take note:P) and the only way of achieving consistency is to tighten your application frequency.

The article also talks about the regularity of applying TE according to their GDD model, which is different from the one I use because it has a base temperature of zero, whereas mine is 6°C. Roughly speaking applying every 200GDD using their model equates to 80GDD using mine. That said, I think their advice of applying every 200GDD provides too long between applications in our conditions,  so you see peaks and troughs in efficacy.

I think you should make your own mind up based on your experience, but what I would say is that it makes no sense applying TE when the grass plant is under stress and that’s where GDD models fall down (IMHO) as a way of predicting TE applications on fine turf, not on outfields, but on fine turf. GDD models will keep on increasing with increasing temperature, but as we’ve seen from the above grpahs, during hot conditions the actual potential for growth decreases, so plant’s do not need growth regulating because the climate is already doing this.

You can download the article here

Rainfall Data

Yep it’s nearly the end of the year and so I’ll be looking to see just how did this year pan out for you rainfall-wise vs. other areas of the U.K and Ireland. If you’re up for it, please email your rainfall stats for 2014 to weather@headlandamenity.com


Just wanted to sign off the last blog of 2014 with a thank you to everyone that’s contributed with comments and feedback over the year. I really do appreciate it and I wish you all a relaxing break over the Christmas period, thanks again.

A special mention to Paul in I.T for keeping it going throughout the year and always having the animated Unisys GIF ready for me when I sit down bleary-eyed on a Monday morning and commit my thoughts to the screen.

See you in the New Year.

Mark Hunt