Monday, 9 May 2016

Grass species on greens

I thought I would do a little blog about our grass species on our greens and some of the things you may or may not notice.  

The good news is we are slowly coming out of the cold spring but the bad news is, as the soil temperatures slowly raise we can end up with greens that are slightly bumpy at times.

Just to put into perspective how cold March and April have compared to prevoius years GDD data. This year is very cold (higher is better).

Grass species

Our greens are made up of a Poa annua and Bent mixture. These two grass are very different but they can produce great greens for the rest of the year. 

One of the differences is the temperature at which they both start to grow. As the Bent grass starts to grow as soil the temperature reaches 6-8 it gets a head start over the Poa. The Poa will sit dormant until temperatures are higher normally around 12, plus it requires higher levels of moisture.

We have already applied fertilisers, top dressed heavily, brushed and verti cut but over the next couple of weeks we will lower the height of cut and groom plus repeating the above to the greens to smooth this out. 

We have applied lawn sand and other iron based products to darken up the greens, this is done to try and help the soil temperatures raise up quicker! 

How can I tell the difference in the grass species? 

If you look at the photo above you will see the Bent grasses (dark green) and the Poa Annua (which is yellowish in colour at this time of year until it stars to grow.

This photo was taken in the rough because it's easier the explain the differences and it exaggerates what you would see on the greens as its happening all over the course. 

If you imagine putting over that piece of rough you can understand why the ball bobbles and chatters while we wait for the consistent soil temperatures to arrive. 

Poa Annua and seedheads?

As some of you may know that the Poa Annua is predominantly an annual grass species (like the name suggests), but it does have some perennial bio- types. At this time of year the Annual reptans seed prolifically (meaning the plant is setting seed out for the next set of plants). 

Poa Annua does seed at low levels all year round but between May and June this increase is noticeable especially on putting green surfaces. Please see the graph below. These readings are based on a metre squared of a green.

Below is a picture of Poa seeds at the different stages of establishment.  

It's hard to imagine thousands of seeds inside just this one sample

This noticeable seed was the main reason that Wentworth rebuilt all the west course greens a few years ago as the greens where seeding during the tournament making hard to get green speeds and stop the ball snaking. A lot of high profile clubs have done this but Poa is one of the toughest grass species and these clubs have to fight to keep this off their greens or plan to relay them every 7 years or so, costing millions to do.  

The rest of us in the country (not including links courses) have to do our best to reduce the seed heads during this period. 

We at Stoneham will always try to increase our Bent grass species in our greens so that there is less Poa around. (Please note we are not trying to remove the Poa totally but just get a nice blend). 

We have been brushing, verti cutting, top dressing, keeping an eye on moisture levels ( as high and low levels will increase seed productivity) and spraying PGR (plant growth regulators) to reduce the seed head numbers. 
I would also like to add that Poa/bent mixed greens still produce some of the best in the country, especially on courses with years of maintenance on them like Stoneham, Sunningdale, Woburn and many more. 

Here is a picture of the seeds on longer areas of grass. This makes it easier to see, again it exaggerates the issues on greens. 

I expect the seed head flush to continue for a couple of weeks especially with potentially warmer weather in prospect. 

We will carry on working hard to reduce these over the coming weeks until this years seeds have gone and we can carry on with our great summer of golf ahead !


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