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