Friday, 25 March 2016

Effective Cultural Control of Poa Annua Seedheads

The greens have a white tinge each spring due to the poa annua seed head.
No, I'm not talking about tearing your greens apart with verticutters to try and reduce the puffiness.  Arguably one of the biggest issues with poa annua is that it will produce seed heads even when maintained as greens height turf. This seed leads to puffy turf conditions which leads to bumpy and slow putting conditions. In Canada, there is no chemical control for seed head on poa annua so we are forced to live with this issue.

Back before I had a roller we would have a very difficult time with seed heads. The greens would be so puffy that it would stall our mowers when we tried to mow them. We would often go out with the verticutters to try and remove some of the seed head material in an attempt to reduce the puffiness of the greens. This often was a failed effort and usually only helped spread fusarium around the already stressed turf. I haven't used my verticutters in years for any reason. I also don't do anything different with regards to fertilizer either as I shared in a post from 2013.

Back in 2010 I started rolling my greens. Since then my issues with the poa annua seed head have steadily decreased to the point where now it's a non issue. I always knew it was due to rolling but what about the rolling was reducing the puffiness of the poa? At first I thought it was simply the smoothing effect of the rolling but this doesn't explain the decrease in puffiness of the poa. I also thought that maybe there was maybe a physiological impact. I first wrote about this in 2012.

Take a look at the top of the rolling head of my roller last May.
Wow, lots of poa seed. That's interesting.
Last May while rolling I made the observation that there was a lot of seed sticking to my roller. I had noticed this in the past but had never thought much of it.

The roller is solid poa seed
It's no secret that I roll a lot. Two and sometimes 3 times a day is not uncommon, especially during the seed head flush in the spring. It appears to me that the act of rolling is actually physically removing the seed from the plant. It's not just squishing the plant down as I had thought in the past.

wow, that's a lot of seed.
So it appears to me that by rolling we can remove the seed from the plant which will reduce the puffiness and most of the negative effects of the poa annua seed head. I also have a feeling that rolling more will actually reduce the seed head more. You will still get the white colour of the seed head but with the bulk of the seed head removed (the seed) you don't get the puffiness.

It is often stated that collecting poa seed is difficult. Well I think I have a solution, anyone want some of supergrass?

I don't think that this impact will be observed on all rollers, however. I have noticed that on larger diameter rollers the seed doesn't seem to stick as well. On my True Turf roller I have 3 rollers on each steering head and each roller is always completely full of seeds after each green. With a larger roller with fewer rolling heads you would probably remove less seed head. The drive roller does not collect seeds on my roller.

There is a lot of discussion among those with access to chemicals which can suppress poa annua seed heads about efficacy and timing. Even if I had access to these products I don't think that I would use them. I would simply roll 1 or 2x each day during the times when the seed head was present and would stop worrying about timing an often ineffective chemical application. I often wonder if some people who have recently started rolling more have been blaming their successes in poa seed head control in a PGR when it might actually be from rolling. Another reason to leave check plots out there.

Lots of seed off a roller after only a single roll on 1 green. Multiply this by 3 rollers and you remove a lot of seed each day! If I had to guess I would say probably 1 pound of seed per green each day for a month. 

A few years ago I did a count of how many seed heads were present on a square inch of turf on my rolling moss study. Here were the results.

As you can see rolling your greens 1x per day could reduce the amount of seedhead by 4-5x! Rolling twice a day could reduce the seedhead by up to 20x!

Since I have started rolling and especially since I have started rolling more than one time each day, I have not had a single issue with poa annua seed head on my greens. They are always smooth and firm and I never get comments about the greens other than the colour from golfers.
The greens are white, but are firm and putt true and fast.

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