Monthly Archives: February 2018

February 26th

Hi All,

As we tip-toe out of February later this week we will at the same time endure one of our coldest weeks of the year. February 2018 will also go down as one of the lowest GDD months we have recorded since we started this process back in 2010. Looking at the stats from my faithful little Netatmo weather station on Weather Underground it shows that for the 26 days of February so far, we have had frosts on 20 of them and given that the last days of February are dead cert frost days, that’ll be 22 out of 28 days frosty, nearly 80% of the month, hardly a surprise then that we didn’t see much GDD or grass growth this month.

As forecasted last week, the Sudden Stratospheric Warming Event (SSW) has indeed reversed the direction of the sub-polar jet stream by pushing the main jet south of us down into The Azores and leaving us with a blocking high sat right over us. The cold easterlies that were predicted when we have an SSW have also come to pass so there we have it, we called it a week before.

It is a major meteorological event, this blocking high pressure is forcing mild, wet air right up into The Arctic causing temperatures to jump there by 35°C and no doubt leading to more concerns about the fragility of the winter ice pack, (already the thinnest it has ever been) meanwhile the politicians sit on their collective fat behinds. (Day after Tomorrow comes to mind)

My our NAO looks negative 🙁

Image courtesy of Metman James –

We also have an extremely negative NAO at the moment don’t you know, NAO stands for North Atlantic Oscillation and is the relationship between what is normally high pressure in The Azores and low pressure across the Atlantic (that’s known as a positive NAO). Well our one is negative because the high is above us, the low’s are below and the oscillation is severe. Why is NAO important ? Well until it swings back positive then you can forget about much in the way of mild weather and growth. It is therefore a good yardstick to watch over the coming days for indications of a change away from this cold spell. You can see from the above that most projections are indicating that this cold weather will be with us (though not as severe perhaps) till possibly Mid-March.

I started a lot of my GDD work back in 2013 when we had a brutally cold spring and people were asking me “How far behind last year are we ?”, I couldn’t tell them definitively so I got to work on using GDD. This spring I think I am going to get that question a lot.

So as we look to the coming week and the threat is of snow, particularly on eastern coasts and The South East / South pushing across to The Midlands and the like at the end of the week. Already I can see the odd large, dry snowflake whisking by my window and this is just the start.

Last week I happened upon a smart weather chap, known as Metman James on Twitter, who is a Meteorology PhD student at Exeter University and we got chatting. He has some great GIF’s and output on his Twitter feed that highlight the weather situation and a prognosis for when it is likely to change. You can find him here.

General Weather Situation

Before I start this forecast I’d like to point it that it’s probably one of the hardest ones to call, first, when and where the snow showers will affect during the early part of the week and second the extent of the heavier snowfall event likely Thur p.m. / Friday. (and when and where it may turn to rain) So don’t whine at forecasts and the fact that it keeps changing, because it will. Just get hooked up to some proper rain (and therefore snow) radar and look not only at where that moisture is occurring but also from which direction it is coming from. That way you’re properly prepared.

Ok so we start Monday after another cracking frost (-2.9°C) and begin a cold and largely dry, bright day with some hazy cloud and sunshine. There is however a risk of snow showers spilling in off The North Sea and this risk will heighten as the day goes on. Already on the radar we can see a raft of snow showers affecting the east coast from Hull south and another band spilling in across Suffolk and Essex across London and into the south of England.  Really anywhere south of The Borders is fair game today for snow showers and whilst these will affect eastern coastal areas initially, they will increasingly push inland so keep an eye out. Wales, the west coast and Ireland will have the majority of the sunshine and in it expect temperatures to leap up to a positively tropical 4-5°C. Elsewhere closer to that moderate, easterly wind, expect this to be more likely 2-3°C with a negative windchill.

Onto Tuesday and a heightened risk of wintry showers, this time more likely to give significant accumulations where they occur. Area-wise I would expect a similar pattern across southern England, East Anglia, the east coast all the way up to Aberdeen this time. We can also expect more significant snowfall further inland over northern England and into Wales I think as well. Similar temperatures to Monday perhaps colder across The Irish Sea as those easterlies extend their hold. Snow is even harder to forecast than rainfall so your best bet is to get onto a website that shows active radar and this will give you the heads up as to where the moisture is occurring and heading. I use Netweather for my output because it’s more national but you can get it specific for your area down to 500m2 which is pretty handy. There are lots available though, Netweather radar can be found here

Wednesday looks a re-run of Tuesday with a harsh penetrating frost and a bright, sunny, cold winters day. Again plenty of snow showers around and as the cold intensifies, the westerly reach of those snow showers extends into Wales and across the Irish Sea into Leinster. Again the majority of snow showers is along the eastern coastline of the U.K but plenty of chances of them moving inland. The wind strength will begin to ramp up on Wednesday and with a colder start to the day and stronger winds I’m not sure the temperature will get above freezing and it will be accompanied by a windchill down the wrong side of -10°C I think ! In other words, bloody freezing.

Thursday, the first day of March, will I think be the coldest day of the week with the hardest frost anticipated down to -7°C I think and possibly colder !  Overnight we have seen plenty of snow showers with accumulations right across the U.K and eastern coastline of Ireland. The suggestion is that the worst snow will be Midlands and north but I think there is plenty of time for this to change yet.

Thursday is very much the change day because we come under the influence of the southern low pressure system that is potentially due to bring heavy snow to many parts of the south of England later in the week. The first thing you’ll notice on Thursday morning is the wind strength as the isobars are packed tight together so the windchill accompanying the severe frost will be down in the -15°C region, seriously parky and not for the faint-hearted. That low pressure system south of England will begin to bring in snow showers and heavier accumulations to the south coast and up towards the M25 / M4 (Oh joy of joys) Expect more in the way of snow across Scotland and The Midlands pushing across Wales and Ireland as well, whipped along by that fierce easterly wind. High winds, bitter windchill and snow showers will continue through Thursday night.

Friday sees I think the highest threat of heavy snow however we are also seeing a temperature lift across the south of England so there’s a great deal of uncertainty of whether we will see snow or snow then rain. I’m thinking more likely the latter across the south of England, Wales and Ireland turning to snow as it moves further north. Temperatures will rise through the day with 2-3°C likely across the south and below freezing across The Midlands north but through Friday evening that milder air will push further north so snow turning to rain with a thaw is likely I think. For many Friday night may be frost-free as that thaw continues into the weekend with Sunday likely to be much milder. Bizarre, bizarre. That strong to gale force easterly wind will continue to blow hard through Friday but will moderate through the latter part of the day. At this stage I think the worst weather will be across The South West, South of England, Ireland, Wales extending into The Midlands. As I mention earlier the likelihood is that this moisture falls as snow initially giving way to rain the further west you go I think.

So the outlook for the weekend….

So we are in the grip of that English Channel low pressure system over the weekend and actually extending through Monday so that means very unsettled through Saturday with high winds, rain, sleet and snow showers principally affecting the south west corner of the U.K, along the south coast and across Ireland and Wales as well. Scotland you are the right end of the country for once but I still expect snow showers for you as well. Again the uncertainty is in what form this moisture will fall, but fall it will so a very unsettled day for Saturday, but feeling slightly milder with southerly / south easterly winds initially swinging more northwards. Across the south of England we may see temperatures up to 7-8°C, but knock that down to 2-4°C for Wales, Ireland and The Midlands north. Again uncertainty about where that moisture will fall but likely to be more rain than sleet across the south of England turning more wintry as it pushes north on Saturday evening. Sunday sees that rain band more across the north of England and perhaps southern Scotland now, falling as rain, sleet or snow depending on elevation. Milder air pushes up behind this moisture band to give a drier day across the south of England, Midlands, Wales and Ireland with temperatures on the up, touching double figures possibly across the south on Sunday. The wind will still be easterly but possibly dropping down through Saturday to a more moderate status.

Weather Outlook

So next week looks like being another complicated one to forecast but at present I expect us to remain unsettled with that low pressure lying in a trough created by a southerly positioned jet stream. That means the low will stay south and then gradually move north and east through the early part of next week so I expect heavy rain, sleet or even snow for the first part of next week down south, drier for Ireland, the west and north though. As we go through the week those easterlies will become northerlies so no quick return to mild weather but perhaps not as cold as this week with less in the way of frost. So a drier end to the week possibly as that low pressure system moves away but staying cold.

Agronomic Notes

As you can see from these wilting Hellebores in my frozen flower bed we have frost desiccation at work this week in some parts of the country. Out walking yesterday it was amazing to walk across 2 ploughed fields that last week left most of the field on my boot such was the stickiness of the soil, to this week when it was powder dry on the surface. This is the result of frost desiccation where water is frozen in the soil and therefore unavailable to the plant, it may also be due to water within the plant itself freezing. As temperatures increase the plant re-establishes its internal osmotic balance and the wilt corrects itself.

Cold temperature desiccation can lead to discolouration of shallow rooted grasses for the same reason as we see in the hellebore above. I took this picture many moons ago and in it you can see bleached patches of I think Poa annua var. annua which were subject to cold temperature desiccation. I expect to see the same occur this week, such is the severity of the frost and in some parts of the U.K, dryness of the soil as well.

For all of you guys that have aerated and topdressed recently then I expect you’ll also see some frost heave where the sand is pushed back up to the surface by the result of ice expansion in the soil down the core holes.

On the subject of soil dryness, I was asked last week to do a rainfall comparison that highlighted what a wet winter it has been across the north-west of England. Frost desiccation won’t be an issue here unfortunately. As you can see from the rainfall comparison above of 3 areas of England, The North West has experienced nearly 150% more rainfall than Oxford or Birmingham. This recent run of cold and frost is just the thing those guys need.

When are we likely to see growth again ?

With many areas of the U.K only experiencing 2 days of growth in February but still experiencing winter wear, it is likely that the pressure for growth will ramp up as we get into March as tees, walkways and winter season pitch areas begin to show the signs of a long winter with very little recovery growth. As discussed at the beginning of this blog, the critical point to watch for is when the NAO switches back away from its current negative value. What this weather jargon means to you and me is that in order for the weather to right itself,  the high pressure needs to move away and be replaced by a milder, westerly airstream and that effectively would translate to a positive NAO.

So what are the weather models saying ?

If we look at the projection for the NAO, it isn’t expected to hit neutral and swing to positive until the middle of March, the models predicting the jet stream position also agree. So I don’t expect us to see much in the way of mild weather until w/c 12th March, that’ll be 3 weeks by then of cold weather with easterly and northerly winds dominating. Now of course all this is a long way off and things can change one way as quickly as they change another but we have had an SSW and the associated easterlies, so a cold 1st part of March is looking increasingly likely.

Thaw on frozen ground risk…

For the areas in line for the main snowfall (south of England, Midlands, Ireland, The South West, etc) on Thursday night / Friday there is a risk of flooding on Friday / Saturday I think. This is because the hard frosts of earlier in the week will have frozen the ground solid to a significant depth and so snow thaw / and / or sleet / rain (depending on what we get) on top of this will have nowhere to drain causing water to perch on the surface. Another potential issue is instability in the surface as it begins to thaw over a frozen rootzone, this can be extremely tricky on sloped areas and certainly presents a Health & Safety hazard until the thaw is deeper and the surface regains stability. One to watch in areas that receive the penetrating frost and then heavy snow / sleet rain and temperature rise shortly afterwards.

Ok that’s me this week, bit of a short agronomic blog but the focus point is more weather than agronomic at the moment. Wrap up well this week, especially on Wednesday and Thursday and keep an eye peeled on the weather radar.

All the best.

Mark Hunt


February 19th

Hi All,

With temperatures into double figures at the weekend in some locations and probably into them today in most, you could be forgiven for thinking that spring is on the way and we have turned the corner from winter. Last weekend I was walking in horizontal sleet and snow with all my layers on, this weekend gone I could have walked in a T-Shirt. Next weekend hmmm more about that below….

Image courtesy of Netweather…

Unfortunately the arrival of an early spring is unlikely to be the case in 2018 because of an event taking place way above our heads in the upper atmosphere known as Sudden Stratospheric Warming (SSW). I am indebted to Mick over the Irish Sea for bringing this to my attention at the back end of last week. A Sudden Stratospheric Warming event is not uncommon at this time of year but its effects on our weather can be profound and prolonged, you can read a full explanation of what constitutes an SSW here.

In a nutshell the occurrence of an SSW can fundamentally disrupt the flow of the jet stream to a point where it stops and even flows back in the opposite direction to its normal west – east flow. This then allows cold air to flow in from the Arctic east / Siberia and we have a prolonged period of cold until it kick starts again. Now the other point that should be said is that there’s no real way of predicting what’s going to happen beyond the 5-day mark forecasting-wise because an SSW doesn’t always result in prolonged cold weather but all the indications are in my view that it will do. The last time this occurred was in March 2016 and before that, January 2013, and you’ll remember how cold those springs were with snow still in the hedgerows at Easter in 2013.

Another feature of an SSW event is that we also see a shift in the position of the jet stream far to the south of the U.K and looking at the output from Netweather for this coming weekend we can see the main body of the jetstream is flowing over North Africa instead of mainland Europe. I for one have never seen it this far south.

You’ll note the deep meandering split from the jet stream over the U.K which will allow a blocking high pressure to establish over us and set in place an easterly airstream that has its origins across northern Scandinavia and Russia. Now eventually the speed and position of the jet stream re-establishes and we come back into a milder westerly airstream and currently the prediction is for this to occur in early March so we are likely to pick up 10-14 days of cold weather as a result of this SSW. I say ‘likely’ but there is great disagreement and uncertainty when an SSW occurs in forecasting beyond 5 days so I must add the caveat of watch this space and your forecasts from the weekend onwards, if you see temperatures diving and the wind direction in the east then the SSW is having its predicted effect.

One last point and it is a positive one for our industry I believe, SSW’s in my experience tend to bring in cold weather from the east but seldom wet weather so if you’re looking for a dry spell to finish off winter projects or just to dry your golf course out then you may well get it.

If you take a look at the Unisys graphic at the top of this blog you’ll see the unusual phenomenon of weather systems moving east to west towards the end of the run, that’s the SSW effect they’re projecting.

General Weather Situation

So Monday starts off mild but overcast for most of us with a band of dissipating rain sitting across central and eastern regions of the U.K in a vertical line all the way from the south coast up to Scotland. Through the morning this will drift eastwards and depart into The North Sea to leave a dull but very mild day for all of us. Ireland the same, dull, cloudy but mild with I think South Wales picking up the mildest temperatures just shy of 15°C, treasure them because you won’t be seeing the thermometer anywhere close again for awhile me thinks. Come the back end of the afternoon we see a new rain front push into west Munster / Connacht and move eastwards across Ireland and also the west coast of Scotland later on Monday evening. Winds will be light and more north westerly I think.

Tuesday sees another mild night / start to the day with temperatures unlikely to dip below 6 – 8°C in most places overnight and almost a re-run of Monday with some light rain sitting across the north east of the country and moving off into The North Sea through Tuesday morning and leaving us with another pretty dull day with the exception of Scotland which will see some brighter weather over central parts through the 2nd half of the day. We may also see the sun across the west of Ireland and along The Bristol Channel. A slightly cooler feel to the day as an arriving high pressure (cue the first piece in the SSW puzzle moving into place) brings a more northerly airstream into play, so 7-10°C is likely in a moderate to strong northerly wind with again Wales likely to be warmest.

Wednesday sees that wind swing round to the north east and so we see temperatures take another dip down from the previous day, this time towards the 5-6°C region and that’ll begin to set the stall out for what may well transpire if the SSW plays out as predicted by some weather models. With any easterly airflow it’s usually the west of the country and Ireland that sees more of the sun because of the propensity for ‘Haar’ and low cloud to push in from The North Sea and that is likely to be the case on Wednesday with brighter spells across Ireland and the west and here we will see the highest temperatures and cloud cover for the east. Dry though.

Thursday sees the wind turn full on easterly and perhaps in the direction we shall be accustomed to for a little while and so a mix of cloud and sunny intervals on Thursday, a light to moderate easterly wind and dry. Not really the end of the world though is it ? We will probably get our first night frost on Thursday night and this will then kick in a succession of night frosts I think dependent on cloud cover. It has to be said that because we have easterlies in situ, then the west will have the best of the temperatures with Ireland perhaps sitting in the 6-8°C range vs. 2-4°C for the east of the U.K.

We close out the week with a much colder day on Friday with again easterly winds in situ. A mix of cloud and sunshine though and dry so really a repeat of Thursday except we are starting each day from a progressively colder base as the degree of overnight frosts ramps up. This will especially be the case for the coming weekend where I think we will pick up some pretty keen night frosts. So dry again and with sunshine and patchy cloud, not a bad day but a pretty cold easterly wind. Temperature-wise I think Ireland will be warmest at 5-8°C and the east coast of the U.K, the coldest, at 2-4°C.

The outlook for the weekend is pretty similar to the end of the week I think but for the fact that we will have some pretty severe night frosts across the U.K, I’d say -3 / -4°C territory with Ireland just staying the positive side of a frost. The other feature of the weekend will be a strengthening easterly wind which will push in more cloud cover and ramp up the windchill so lower day time temperatures and less in the way of sunshine for central and eastern areas with the best chance of seeing the sun across the west. Truly bitter weather for sure so wrap up well with a negative windchill likely.

Weather Outlook

As mentioned right at the start of this blog there is a great deal of uncertainty surrounding where the weather is likely to go after the weekend with broad disagreement between models but I’ll pin my flag on Unisys’s interpretation and we will see how we get on. So I’d say next week looks to be a bitterly cold one with biting easterly and north easterly winds pushing cloud cover in off The North Sea, ‘Baltic’ would sum it up. There may be a risk of wintry showers from eastern and central areas as a nearby low pressure feeds moisture into the airstream but currently this doesn’t amount to much (but we will see). There’s a sneaky low pressure passing very close to the south coast later on next week and this will be one to watch if it nudges northwards but at this stage it is set to miss us. Later in the week the wind edges round to the north east to rachet down the temperatures even more. The only saving grace is that it’ll be mainly dry but I think we will have a run of successive night frosts starting at the end of this week and continuing for at least 10 days. Now that’s one interpretation, there are others but time will tell who has the correct handle on predicting our weather under the influence of an SSW. If they are right it won’t be till around the 5th of March before the job rights itself again.

Agronomic Notes

Following on from last weeks blog on spring aeration and whether March and April are the best months for us to do this I just to wanted to clarify my viewpoint.

The gist of what I was trying to say was that we have to cut our cloth to suit and so if the weather outlook / GDD looks grim for the next 7-10 days in March / April, then I don’t see the point in double hollow coring, Gradening and the like if your expectation is for poor recovery. Fine to do that in January if ground conditions and O.M levels dictate that this is feasible / necessary but not for early March if we are stuck in an easterly airstream as indeed we may well be. So I’d rachet off my spring aeration if conditions aren’t conducive to recovery but on the understanding with your club that it still needs to be done at another point in the season.

This point is typically August because with summer holidays and the like, it is often quieter from a play perspective, we have optimum growing conditions normally and provided you have the resources and an irrigation system that works, I see no reason why you can’t gain recovery in 7-10 days from aggressive aeration. The greens are then set fair for the autumn and what is now one of the most popular revenue months of the year, September.

There’s a flipside to this coin and that’s if the weather outlook / GDD looks optimum for recovery and here you could up your game in terms of organic matter removal because you know the conditions for recovery are likely to be good.

Let’s look at the last 7 years from a GDD prespective and see how an early and late spring pan out in relation to an SSW event.

We can see from the above that over the last 8 Springs we have had 3 SSW-related cold snaps and this has really affected the amount of growth as determined by GDD.

So in essence what I was saying last week is summed up in the graph below, i.e if we are looking likely to have a cold spring think about if you are going to aerate and perhaps as importantly, how you are going to aerate….

So the graph below shows a comparison of two springs, one in 2016 when we had an SSW event and subsequent cool March and April, the other 2017 when we didn’t. It assumes we aerated on March 1st in both years and that soil moisture and nutrition were in place to gain recovery. It also assumes a total Growth Potential of 4.0 is the magic figure to gain recovery from 12mm hollow coring at 2″ spacing (mixture of units there, sorry it’s just habit)

So there you have it, 15 days in a good spring and 35 days in a poor one…

Plenty of pecking out there…

Well it’s clear the Corvid species (Rooks, Crows, etc) haven’t been watching the long-term forecast because these guys were laying eggs in January and now have some hungry mouths to feed. That has resulted in alot of reports of pecking activity around greens, tees and the like. One club I visited last week had put up some rotating Crow scarers which were having some effect (if you kept moving them) and also a model of a dead crow which looked very life-like. (or dead-like I guess ?). The culprit in the above case was immature Chafer Grubs, clearly recognisable with their defined head vs. Leatherjackets. And of course we have nothing to treat either so it’s a case of trying alternative methods as described above or grinning and bearing it for the time-being I’m afraid.

Ok that’s it for this week, let’s hope all the projections are wrong and the SSW doesn’t have its predicted effect on the weather and spring arrives on time 🙂

All the best.

Mark Hunt





February 12th

Hi All,

So we’ve reached the mid-way point in February but you know this winter is really starting to drag on a bit. (sorry Adi bit it is) Out walking yesterday I endured lovely sunshine, horizontal hail, sleet and lovely big snowflakes, it really was a lottery. Lovely to be out though and I happened upon this intriguing carving on a public footpath waypoint….It did appeal to my Danish heritage 🙂

So are we set for a continuation of winter or do we see the first signs of an early spring, remembering that last year the end of this week signified the arrival of mid-teen temperatures and the start of growth ?

General Weather Situation

So we start the week with a cold, bright day after a hard frost and some overnight snow for Scotland, the north west and south west of England and Ireland. During the morning the winds will swing round to the west and that will herald in slightly milder air pushing temperatures up to 6-7°C at best. Now they’ll be some wintry showers around, chiefly in the west of the U.K with more than a smattering across Scotland, the north west of England and Ireland and the odd one moving across South Wales and The South West. For most though it’ll be a lovely, cold, bright and settled winters day with nice afternoon temperatures. Late on Monday night we see a rain band push into the west of Ireland and this will fall as a mix of rain and wintry showers as it crosses Ireland overnight.

Overnight into Tuesday and that band of rain and wintry showers has largely cleared Ireland and makes landfall along the west coastline of the U.K butting up against colder air and falling more as wintry showers than anything else. Further south across South Wales and The South West this may manifest itself as heavy rain unfortunately. This vertical band will move eastwards across the U.K so if you start dry it won’t be for long with more wintry showers than anything over Scotland and the north of England, really anywhere where there’s some elevation. Ireland should start clear, dry and sunny after the rain moves through but still with a risk of wintry showers across the west and north. By lunchtime that band of rain is across to the east coast of the U.K clearing westerly and central areas as we approach sunset. Clear skies at this time of year mean frost and that’s what I think we will see on Tuesday night. A really miserable day, dull, wet and cold with temperatures lucky to hit mid-single figures.

Mid-week beckons and with it another front of rain and wintry showers crossing Ireland in the early hours of Wednesday morning and moving into western Scotland and the west coast of England and Wales close to the morning rush hour. With cold air sitting over us it is likely this moisture will again fall as snow at elevation turning to rain as the temperature rises through the morning. Most of this moisture front will stay firmly rooted to the western coastline but I think we will see some rain move inland later in the day. A wet day for Ireland then with wintry showers turning to rain as it moves across country clearing the west during the morning and the east of Ireland by tea time. Wednesday afternoon sees that band of moisture turn increasingly wintry again as it moves eastwards inland across the U.K, so another wet day beckons I am afraid for many of us. It may take till dusk to reach the east coast of England and here it’ll be falling as rain I think. So another dull, cool and to be quite honest, crap day with plenty in the way of wintry showers and rain around. 🙁 The only plus point I can make about Wednesday is that the wind swings round to the south and this will usher in some milder night time temperatures I think, so no risk of forst on Wednesday night.

Thursday sees another band of rain, sleet and snow past eastwards across Ireland and the U.K overnight so by the time the sun comes up on Thursday morning most of it should have cleared through with the exception of the east coast of England and western Scotland. Thursday looks a much better day for most of us with dry, bright conditions, a brisk westerly wind and better temperatures pushing up close to double figures in the south of England though cooler across the west. They’ll still be some wintry showers around across Donegal and more intensely, the south west / north west of Scotland but on the whole, a much better day.

Friday sees another dry start, although colder at night with a risk of ground frost. They’ll be a band of moisture pushing into Connacht and south west Scotland from early doors and this will move diagonally (/) across Ireland and the west of Scotland during the morning and afternoon clearing behind it. For the areas not affected by this band of moisture, it’ll be a sunny day with some hazy sunshine and light to moderate south westerly winds and crucially, dry again. Temperature wise I think we will be 6-9°C, with the lower temperatures under that cloud and rain in the north and west and the highest down south.

So how does the weekend look ?

Well some good news possibly…

I think we will see an Atlantic high pressure edge in during Saturday and that will bring dry and slightly milder air across the U.K and Ireland. Owing to the fact that it’s coming in from the west I think we will see Ireland warm up first with double figure temperatures likely to be on the cards. There is a risk that Friday’s band of moisture will sink south on Saturday morning across The Midlands and East Anglia but it may just fizzle out by the same token, one to watch closer to the weekend. It would be warmer but we will have northerly winds in situ and they peg back temperatures to the high single figures on Saturday and Sunday, but crucially I think it’ll be a pretty dry picture for nearly all of us with perhaps the north west of Scotland still hanging onto some wintry showers.

Weather Outlook

So next week looks like that Atlantic high pressure will be sitting over us, albeit perilously with a strong low pressure system sitting north of Scotland. So there’s a risk there of moisture pushing in between the two weather systems next week but I don’t think it’ll amount to too much in the way of rain (famous last words). It is quite a complicated weather picture because although high pressure is projected to sit over us, it will be squashed between other weather systems, so it’s not a dominant high. When this happens it is my experience that sneaky low pressure systems can slink in and affect things so although I’m forecasting a pretty settled and dry week, next week, we will know more closer to the event. I don’t think it’ll be particularly warm either because I don’t yet see signs of warm air pushing up from the south as it did this time last year.

Agronomic Notes

I’ll start this week with a picture that dropped into my intray last Tuesday morning from a certain Mark Todd. The title of the email was “Extreme Coring” and I just couldn’t stop laughing. Mark, I take my hat off to you and your guys 🙂

So this brings me onto the perennial debate about spring aeration and whether we are missing a trick in some instances. I think I’ve talked enough about trying to aerate early in the season and use the weather windows if and when they present themselves (Although Mr Todd’s interpretation of a ‘weather window’ probably leaves something to the imagination :)).

I do wonder though whether the whole subject of spring aeration needs a re-think.

Traditionally we aerate in March and April and then again during the autumn with many clubs pushing the latter back past the last significant fixture. Sometimes that might be October or November and to be honest I’d question the wisdom behind this.

First off why are we aerating ?

Joining the dots….

Now I know we have lots of different approaches to aeration but essentially we are interested in controlling organic matter in the surface, facilitating water movement through the profile, decompaction and maximising oxygen availability to the grass plant. Nowadays we have a myriad of machines and techniques to help us achieve this in a fraction of the time it would have taken to do the job 20 years ago and that can only be a good thing.

There are though two sides to every coin…And it’s a hard call in this day and age of increasing competition between clubs, increasing expectation on behalf of the golfer and a more nomadic end-user who is more than happy to ditch the booking if aeration (or look for a discount) has been been carried out recently or is planned.

By the same token I also think it’s a hard call in terms of communication on behalf of greenkeepers and groundsman alike, the surface is good but we have to aerate to keep it that way and of course alot of our work is aimed deeper down the profile where the results aren’t readily apparent. Putting that over from a communication perspective isn’t always straight-forward.

So lets look at March and April in 2016 and 2017 and see what the potential was for aeration and most importantly, recovery.

Spring Statistics 

So I thought I’d haul up some stats and look at a ‘typical spring’ if such a mythical creature does indeed exist. I have collated and recorded the number of wet and dry days, the number of frost days (defined as a minimum air temp < 1°C) and the number of good growth days (defined as a daily G.P ≥ 0.4)


In spring 2016 we can see that at the Bristol location they had a very hard spring with no days of good growth in March, yes that’s no days at all and a whole 7 days in April. That doesn’t tell the whole story though because April 2016 was very dry with no recorded rainfall on 22 days, so it is a possibility that even when it was warm enough for growth, moisture may have been a limiting factor.

Indeed if we graph out rainfall and Growth Potential (above) we can see that on the days when day and night temperatures were high enough for growth, there was little or no rain, so certainly moisture availability was a potential issue. We then have the other perennial debate, when to get the irrigation system fired up !

This is a common feature of the month of April, dry conditions and also cold, because we recorded 4 frosts in April with the majority in the last week of the month.

Moving across to The South East of England and we can see a different picture at the Guildford location with more growth in March and April as we would expect. More growth yes, but only 27% of the days in March and April were conducive to good growth and again the same pattern of dry days in April albeit with less frosts at this location.

It would be wrong to ignore the north of the country and here we can see how truly hard it was to generate consistent grass growth in the north of England (York) in spring 2016. So on only 3 days out of a maximum 61 during March and April was it warm enough for good growth and again we see the pattern of frosts continuing into April with 18 frost days recorded for March and April combined. Less dry days as well because most frontal systems in the spring tend to affect the north and north west rather than further south and east when we look at the U.K.


I think alot of people would rate spring 2017 as a good spring in terms of grass growth, so let’s see how it shaped up across The Irish Sea in Cork.

So again we see the same pattern  with only 25% of the days in March and April conducive to good growth (from a temperature perspective). We also see the same pattern of a high number of dry days in April and frost though admittedly only on a single day :).

From a revenue perspective though you’d probably look at it completely differently with less risk of closure, a majority of dry days and more chance of getting golfers round.

Closer to my neck of the woods is this Northampton location where we see a pretty good picture for March in terms of growth, but still only 30% of the days available mind. April 2017 again shows more dry days and more frost with coincidentally most of the frost days in the last week of the month, the same as 2016.

How much growth do we need for recovery ?

Off the top of my head I think you need 10 days of G.P ≥ 0.4  (so a total accumulated G.P figure of 4.0) to get recovery from a hollow coring using 10-12mm tines at close spacings. Now of course there are plenty of variables circulating around this comment, not least adequate moisture, good nutrition and a grass species that grows well at low temperatures.

So if I hypothetically cored on say March 1st, this is how long it would have taken to get recovery at the locations above assuming the Growth Potential figure is accurate and moisture / nutrient levels were sufficient to promote growth.

Bristol 2016 – 34 days

Guildford 2016 – 28 days

York 2016 – 34 days

Cork 2017 – 18 days

Northampton 2017 – 15 days

So in a poor spring we can bank on a month before we gain sufficient recovery if we aerate in March or indeed April I think and in a good spring this figure drops to 15-18 days odd in the locations I have analysed. Obviously as we go head north into Scotland this will extend even further.

Lots of questions really generated from this, not least why are we aerating at a time of year when recovery is a minimum of 2-3 weeks and in some years you can 2X that ?

Well, it’s traditionally been the time we aerate, but of course now it’s the time when golfers are coming out from winter hibernation and expect good surfaces because after all Augusta or some other tournament course is on the telly and their surfaces are excellent….More often than not it is the only aeration slot provided in the calender where significant organic matter removal is planned for.

Is this a good state of affairs for our industry  going forward ?

I think not.

I think going forward golf clubs, sports clubs, greenkeepers and groundsman alike have to sit round a table and work through the aeration that they know they need to do (obviously backed up by organic matter figures and the like) and look at when is the best time to achieve it rather than the only time available between fixtures. We also have to look for those windows and exploit them and that requires flexibility (and machinery) because if aeration goes out the window, it’s going to be harder and harder to provide good surfaces, particularly from a disease perspective. We also know you can have the best rootzone in the world, but if you have a 10mm layer of compact organic matter above it, your surfaces will sit as wet as puddings regardless….

I’ll leave with the same picture I started with and joking aside at the end of last week this club had a big tick in the box of organic matter removal on greens and approaches, as daft as the picture looks…I know this isn’t workable for everyone in terms of ground conditions, machinery, resources and the like and I’m not daft enough to think it is. I am just making the point that we have to re-think when we do the work (rather than if we do it) and play to our strengths rather than in some years, our weaknesses.

The above rhetoric is also based on the benefit of hindsight and I’m sure there are plenty of people reading this with an aeration date already in the calendar for March or April. All I’d say here is closer to this date look at the 7-10 day forecast and work out your total G.P figure, if it looks very low then maybe a change from hollow coring to solid tining should be in order with a committment to hollow core later in the year or perhaps a change to smaller tines at closer spacings ? (Although I readily accept this has a finite limit when filling the holes with sand becomes impossible to achieve)

All the best for the coming week and fingers crossed that high pressure comes our way and gives us some nice respite from the frequent rain and wintry showers 🙂

Mark Hunt



February 5th

Hi All,

Beautiful to see the first signs of spring out walking yesterday though there won’t be much spring-like about the weather this week as we pick up some pretty cold air across the southern half of the U.K in particular.

February is traditionally our coldest month of the year as we all know so I had to admit to a smile when I saw a headline proclaiming “coldest week of year coming up” in a tabloid yesterday. Wow that must have taken some thinking about….It’s not a straight-forward case of cold and dry this week because we have low pressure sitting north of us and that will push some moisture into Scotland and the like through the week.

Ok onto the detail…

General Weather Situation

So Monday starts pretty dry everywhere but with a north east wind we are likely to see some snow showers pushing in from The North Sea into eastern and south eastern parts through the day. Areas most likely affected are the South East, East Anglia and Humberside. Otherwise a calm, dry and settled day just about everywhere with sunny intervals breaking through later in the day and a quiet, north easterly wind. Those snow showers look to drift in to eastern coastline of the U.K throughout the day but they’ll be pretty hit and miss so best to check your rain radar to see if any are coming your way. Later in the day we will see a band of moisture pushing in from The Atlantic bringing rain and wintry showers to the west coast of Ireland overnight. Temperature-wise 3-5°C is all you are likely to see on the old thermometer with a hard ground frost overnight leading into the day. (We were -1.6°C here)

Overnight into Tuesday and that front of wintry showers will be sitting across the east coast of Ireland, western and central areas of Scotland and north west England by the start of Tuesday morning rush hour with a lot of snow wrapped up in that moisture. As we go through the morning that band of wintry showers will sink south into Wales and eastern, northern England, however south and east of this it’ll be a dry, cold and bright start after a sharp overnight frost where temperatures are likely to drop to -3°C. We may just see some showers push further inland into The Midlands but we’ll see, currently this isn’t forecast.  As we go through the afternoon those showers will sit in a band stretching up from Wales through northern England and across to The North East with Scotland clearing to end the day with a nice, bright, cold, clear afternoon and evening. Ireland will have a dry, bright and clear day after those wintry showers depart the east coast during the late morning but we may well see them make a return into Connacht and Donegal later in the afternoon. So another bright, cold and dry day away from those wintry showers and with the wind turning more northerly I’d expect it to feel even colder with temperatures barely breaking freezing in the wind, maybe 2-3°C tops.

Mid-week already, how time flies when you’re freezing your nads off and Wednesday promises another largely cold, dry and bitterly cold day with a penetrating ground frost overnight perhaps down to -4°C in areas. With the light wind swinging round to the north west, it’s the turn of western coasts to bear the brunt of wintry showers with Wales, The South West and the western coast of Scotland at risk through the morning. Dry, bright and cold everywhere else so a great week to crack on with winter project work if you are able. Cloud cover may persist over Scotland and northern England through the afternoon and this will thicken to bring some more wintry showers along north western coasts as we close out the day. Ireland looks to start dry, bright and cold but cloud cover will thicken through the afternoon, it should stay dry though.  Again 2-3°C tops temperature-wise across the U.K and maybe 6-7°C across Ireland.

Moving into Thursday and overnight a weak band of rain and wintry showers has pushed into western Scotland and north west Ireland moving south and east by dawn. This moisture will likely fall as rain across Ireland as a change in the wind direction heralds in slightly milder air temperatures. As that moisture over Scotland and Wales meets the cold, continental air expect it to turn more wintry in nature. Through the morning that rain crosses slowly over Ireland and into the north west of England and Wales falling as snow over Scotland. This band of moisture is persistent and although it slowly clears Ireland during Thursday night it will turn more wintry in nature across the north and east of Ireland, Wales, the north west of England and Scotland pushing cloud before it. So a dry, bright and cold day for central and southern areas of England but through the day it’ll become cloudier as that band of wintry showers pushes moisture ahead of it. Similar temperatures to Wednesday with 2-3°C tops across the U.K and maybe 6-7°C across Ireland again.

Friday sees the highest threat of moisture to the southern half of the U.K this week with that band of rain and wintry showers moving south and east overnight so we may start Friday morning wet with a mix of rain, sleet and snow extending all the way down into The Midlands. The boot is on the other foot on Friday because after a soggy Thursday, Ireland and Scotland look to have a bright, cold and dry end to the week. Through Friday morning that band of moisture will sink south and east affecting all areas before it eventaully moves off into The North Sea by the late afternoon. Another cold and dry end to the day and that means a penetrating frost for all of the U.K and Ireland on Friday night I reckon with a risk of wintry showers still for the north west coast of Ireland.

The weather at the end of the week pretty much shapes the beginning of the weekend because with a bright, cold and dry night we will all have a penetrating ground frost to start the weekend. So Saturday looks cold, dry and sunny across all areas with a really cold northerly wind dragging temperatures down towards a negative windchill. So it’s a winter walk, wrap up warm sort of day if you feel disposed to do so, except for Ireland where I think you’ll see a dry first half of the day but increasing wind and cloud will push rain in for the 2nd half of Saturday. Sunday sees the wind swing round to the west and gather strength, particularly over the north of England, Scotland and Ireland so milder but more unsettled with an increased risk of showers for the 2nd half of the weekend.

Weather Outlook

So next week looks like it’ll start with a North-South split in the weather with the south hanging onto that cold, dry, high pressure for a few more days. The north and west will come under the effect of another Atlantic low pressure system which will bring unsettled, windier weather in from the off and a milder westerly airstream. At present it looks like this low pressure system will sink south and exert its effect across all of the U.K and Ireland as we approach mid-week settling into a strong westerly wind, milder temperatures and some rainfall of course.

Agronomic Notes

As it’s the first blog of February it gives us a chance to look back at January and see what hand we were dealt.

GDD January 2018 – Thame Location

So we can see at this location we put on 30.5 GDD which is pretty normal really as January’s go and reflects some positive growth periods during the month, more on that later. No real point in doing a cumulative so we’ll cast our net around the U.K and Ireland and look at both GDD and rainfall.

UK Locations – GDD & rainfall data

The first point that is very obvious about the above chart is the huge amount of variation in rainfall levels with the Northampton location, the driest and Okehampton, the wettest.

The difference between the two is a rather mid-boggling 163mm !

There’s a clear west – east divide for the U.K when it comes to rainfall and as you’ll see from the Irish data, this is true there as well. Growth-wise we have evidence of a pretty cold January in Scotland with a GDD of only 6.8 recorded for Fife compared to our Thame location which showed 30.5 total GDD for the same period.

Looking at the growth patterns for the month we can clearly see the difference between 3 UK locations as we cover south to north…

All 3 locations show similar patterns of growth but not magnitude with the most southerly location warmer as we would expect. The phrase “No one size of hat fits all” is clearly true when we look at the potential for taking advantage of this growth by carrying out early organic matter removal / aeration. Clearly although Fife and Thame shared similar rainfall totals it’s obvious that whereas we would have seen some growth and recovery in the Thame location from any January work, we would have seen nothing in the Fife location.

Ireland Locations – GDD & rainfall data

Ireland follows a similar pattern in terms of GDD and rainfall but you can clearly see where the rainfall bias was !

So the east / south east coastal locations of Dublin and Wexford came off lower rainfall-wise, some 50-60% less than the west of Ireland that got clattered I’m afraid during the month of January.

Growth-wise we have the shining star that is Valentia with a GDD total of 67.4 compared to the lowest GDD in Claremorris and also Dublin of around 20. With temperature in January comes rainfall though and so the highest GDD location is also the wettest with nearly 10″ of rainfall 🙁

Again the same dynamic in terms of growth would have been present but with so much rain falling in January over most of Ireland I’d be doubtful if anyone managed to get some aeration done successfully even if there was some good growth windows evident as we can see below ;

Growth Windows

In some locations, the period from Jan 22nd to Jan 29th showed some good growth albeit with a drop off on the 26th and 27th and this window was enough to provide some great response from early season-applied granular and foliar fertilisation.

I think granular nutrition is often more effective at this time of year because you have better resistance to leaching (particularly if the formulation is slow release, controlled release, organic) and better longevity as well.

You may ask “What’s the point of fertilising so early” but for me if you have such a growth window (and clearly not everyone did) then why not get the plant growing or ‘primed’ in readiness for growth ?

Any growth benefit gained now means less growth requirement once we reach the spring good and proper and with a propensity to have drier springs, using these windows now can be more reliable than those later into the spring, particularly from a moisture perspective. I’m going to guess that in the latter part of next week we will pick up a milder airstream and a return to growth and so if the grass plant is ‘primed’ it can take advantage of this whereas trying to kick start it during the window means an inevitiable lag.

There is a counter-argument I know that the grass plant growing the most at this time of year is Poa and by encouraging this plant to grow, you tip the balance in favour of it vs. other grass species. Of course on a lot of surfaces, Poa annua IS the dominant grass and so I could chuck in another counter argument which would be that growth at this time of year from Poa means better recovery from autumn disease scarring and a tendency to out-compete other plant species like moss. Like so many things in life it is horses for courses….

Ok that’s me done for another week, wrap up well this week with all that cold weather around and let’s hope that next weeks milder weather signal does indeed manifest itself.

All the best…

Mark Hunt