Frost and USGA spec greens!

[delc]

Our course has USGA spec greens, which are built over stone and gravel bases to give good drainage. Only problem with this is that the stones act as a heat (or cold) sink and our greens remain frozen long after the rest of the course has thawed out. At the moment we have a generally green course with white greens!

 

[Lord Tyrion]

Yes, but for the rest of the year you will have wonderful greens.

 

[duncan mackie]

Our course has USGA spec greens, which are built over stone and gravel bases to give good drainage. Only problem with this is that the stones act as a heat (or cold) sink and our greens remain frozen long after the rest of the course has thawed out. At the moment we have a generally green course with white greens!

I think something is very wrong here - the temperature at the depth of the 'stone and gravel base' is going to be warmer rather than colder so by your logic the greens would be green first!

 

[delc]

I think something is very wrong here - the temperature at the depth of the 'stone and gravel base' is going to be warmer rather than colder so by your logic the greens would be green first!

Scientifically speaking, the Earth cools down overnight by radiating heat from the ground upwards. The stones and gravel under our greens are not deep enough to get any significant heating from the Earth's core.

 

[Deleted member 15344]

I think something is very wrong here - the temperature at the depth of the 'stone and gravel base' is going to be warmer rather than colder so by your logic the greens would be green first!

I agree - the stones are supposed to keep the heat which helps the greens have less frost

 

[delc]

I agree - the stones are supposed to keep the heat which helps the greens have less frost

But that is not what happens! As I have already explained the Earth cools down overnight by radiating heat from the ground upwards. This is why you can get ground frosts when the air above is several degrees warmer. The stones and gravel act as a heat sink, so that they remain colder than the general environment after a cold night, and for that matter warmer after a hot day.

 

[Deleted Member 1156]

Don't argue with Delc, he knows what he is talking about

 

[Region3]

Our greens are always the last thing to thaw, but I always put it down to the shorter grass freezes more than ground with longer grass.

 

[garyinderry]

You get ground frost with warmer air due to tightly packed ice particles that take longer to break the bonds compared to faster free moving particles of a gas.

Simple chemistry no?

 

[Foxholer]

But that is not what happens! As I have already explained the Earth cools down overnight by radiating heat from the ground upwards. This is why you can get ground frosts when the air above is several degrees warmer. The stones and gravel act as a heat sink, so that they remain colder than the general environment after a cold night, and for that matter warmer after a hot day.

In Greenkeeping terms, that's why you get 'air frost', which is not such a bad thing. A 'ground frost' is when, in addition, the ground temperature is such that the roots of the grasses are frozen. This is the condition that is dangerous for Greens, as while the thaw is from the surface down (irrespective of whether the Greens are USGA spec or not) there is a time when a ball landing on the thawed surface will crush the frozen roots of the grass, killing it!

It is not just whether or not you have USGA spec greens, but also how long the the temperature is/was below freezing - and by how much - and how deep the sand/soil layer is as well! USGA spec Greens will take longer to thaw from a 'ground frost' though.

If you want Greens that are playable when there is a ground frost, then install some underground heating! But expect to pay considerably more for your subs! Or go to abroad to play during the depth of Winter - South Africa for example.

Btw. Links courses often suffer less from ground frosts than inland ones as the nearby sea moderates the temperature difference too!

 

[Whereditgo]

Ground frost is (surprise, surprise) measured at ground level, air frost is measured at 1.2m above ground - therefore there can be a significant difference between the two! There is such a thing as a grass frost too, which occurs when the temperature at ground level over solid surfaces (concrete, tarmac etc. which cool more slowly) doesn't reach the freezing point of water, whereas over soil / grass the temperature reduces quicker.

 

[duncan mackie]

Scientifically speaking, the Earth cools down overnight by radiating heat from the ground upwards. The stones and gravel under our greens are not deep enough to get any significant heating from the Earth's core.

I think you are now confusing yourself to fit your initial statement.

Go out and measure it yourself - I did this morning. Lowest temperature was at about 2" deep at the time I posted (2.3 degrees) but it would have been more towards the surface first thing, not deeper. By 4" it was up at 2.7 degrees.

 

[delc]

Our greens are always the last thing to thaw, but I always put it down to the shorter grass freezes more than ground with longer grass.

I don't think it's anything to do with the length of grass. Yesterday we had a fairly cold night, down to about minus 4 degrees, with a light covering of snow. The next morning was just about warm enough to melt the snow and most of the course, including the closely mown fairways and tees, were free of lying snow by 10 am. However the greens remained snow covered until after midday, and even after 1 pm, when I played, they were still frozen hard while the rest of the course had softened up. I can only attribute this to the heat sink effect of the stones and gravel that make up the bases of our USGA spec greens, causing them to heat up more slowly than the surrounding ground.

 

[Foxholer]

I think you are now confusing yourself to fit your initial statement.

Go out and measure it yourself - I did this morning. Lowest temperature was at about 2" deep at the time I posted (2.3 degrees) but it would have been more towards the surface first thing, not deeper. By 4" it was up at 2.7 degrees.

Just for a change, I'm more with Delc on this one!

The actual conditions are hugely important though. If it has been sunny/warm during the day before, then the ground will absorb energy, then radiate it. If it has been overcast and cold (Britain's normal November to March style), and sufficiently cold, then the ground will be frozen. And the proximity to water and/therefore breeze will have an impact too!

The simple answer is .... it depends!

And the Greenkeepers are the ones who should know, so either trust them or sack them!

 

[Tashyboy]

Played Sherwood today for the first time and it's a stunning course.

However it was temp greens on every hole, Gutted is a massive understatement.

i know it's been cold but the last two days have been the sunniest in the last month (solar panel readings) there was no frost an a smothering of snow on one hole.

Yet you struggled to put your tee in the ground. loved it, it kicked me ass but the temp greens call was the green keepers. Still gutted though.

 

[stevelev]

DelC Who really cares that much.

Have you ever thought of joining an amenity and horticulture forum, along with a meteorological forum. That way rather than chatting thought you could actually enlighten us with a fact for once.

 

[duncan mackie]

Just for a change, I'm more with Delc on this one!

The actual conditions are hugely important though. If it has been sunny/warm during the day before, then the ground will absorb energy, then radiate it. If it has been overcast and cold (Britain's normal November to March style), and sufficiently cold, then the ground will be frozen. And the proximity to water and/therefore breeze will have an impact too!

The simple answer is .... it depends!

And the Greenkeepers are the ones who should know, so either trust them or sack them!

I agree

but

at 6" + down the air temp conditions would have to be extreme (and way beyond what we have experienced this year in this area - referenced in my post) for it to become the factor mentioned ie permafrost conditions!

 

[patricks148]

must be more too it than ground/ air temp etc.

was out with the dogs last night and walked across Torvean, the snow was gone on most of the course and the fairways were clear, but,

the greens had frost on as did the temp greens which are a good 30 yards in front of all the greens and are just cut on the fairway.

So why does a round patch frost up??