Bumpy Greens

Bumpy greens!!!???

There have been several burning questions buzzing around recently namely “the greens are dry and why are they bumpy”

The simple answer is we have Poa Annua dominated greens and it hasn’t started growing yet, this raises a couple of questions i.e. what is Poa Annua and why isn’t it growing?

Poa Annua

Annual meadow grass by its common name is widely regarded as a weed turf species, colonisation is usually facilitated by incorrect turf management usually too much water and over fertilizing but the truth is most courses if not all courses have meadow grass greens to some degree or another and have to learn to manage it.

The accepted turf composition for a golf green is 80% bent & 20% fescue, unfortunately this composition is difficult to achieve even when the seed/turf is made up of these percentages during construction, because of the drive to have soft lush greens this negates the requirements of the desirable species. Phoenix greens composition is made up of Poa Annua bio types (more on this later) Rye grass, bent grass, and if I look hard enough I may be able to find a leaf or two of fescue but I’m not holding my breath! (hates too much water)

So now we realise that we have possibly four types of turf, right? Wrong try 100’s or 1000’s this is where the Poa bio types come in.  Cast you mind back to early March and the greens had a purple patchy appearance and the patches varied in colour saturation, these differences are the different bio types and the green bits were the “other” grasses. All these patches grow at different rates and some are still dormant or just coming out of dormancy, the Rye component grows at low temperatures that is why winter sports pitches use it so as to aid recovery. Imagine Rye growing actively, all the Poa bio types growing at different rate and the “other” grasses trying to catch up the result is bumpy greens until the air/soil temps rise to a reasonable number and they are all growing into the mower clipping zone on a daily basis.

But they are dry!

It’s difficult to warm something up and wet it at the same time! As we have mentioned we desperately need the air/soil temps to rise to facilitate growth but at the same time turf does need water and if it’s not forthcoming from the sky we need to irrigate for short bursts that give the turf water but doesn’t saturate the green and lower soil temps.

Whats the optimum temperature for growth?

Cool season grasses (uk) have an optimum growth potential of 20c (air) and 18c (soil) above and below this the turf growth slows, as an example 1c and 30c could have similar grow potential! A little exaggerated but you get the idea.

Then we have “growth degree days” this indicates the days that turf has entered the growth zone and this April is 50% lower than average!! Look at the diagram for illustration.

What can be done?

As of the 9^th May take a close look at the greens and you will notice small dark green circles, these are the remnants of the aeration work we did earlier and the roots are in a better environment and are extending gathering nutrient and because they are longer they are protected from the fluctuations in soil temperature’s, I measured the soil temp today on the 17^th green at 50mm deep and recorded 8c you can deduct that about 10% growth potential is produced, not enough to kick start the greens.  

I hope this explains things but as with all nature driven processes there are millions of variables and no simple answers, please feel free to ask me anything about the Royals Greens if you see me around the course.

The black column is this April 

We should have 75% GP but have about 10% thats why the greens are bumpy!