Friday, October 2, 2009

Why do we topdress greens?

Look no further than the above picture to find the answer to that question. This plug was cut out of #12 green just before we mowed down the turf with the fresh blades I mentioned in the last post. Notice how the very top of the soil profile is lighter than the rest. This is fresh sand that is clean of organic matter and it serves more than one purpose.

1) Sand works its way into the turf canopy and settles in between the crowns, or growing points, of each plant. The crown is partially buried and therefore protected from scalping by the mower blades. If we see scalping on the green we know we need to topdress before disease and thinning begin.

2) Sand helps to break down organic matter by increasing porosity and helping the soil breathe. This is why you do not see any distinct layers from top to bottom. We try to topdress every two weeks with a light dusting and apply twice at heavier rates during our spring and fall aeration. We fill all the holes to improve drainage and porosity, but keeping some sand on the top is also very important.

3) Faster, firmer greens. Sand fills in slight imperfections to allow better ball roll and firms up the surface since sand holds less water than organic material in the soil below. I know many golfers feel that sand on the greens equals slow greens. I have a stimp meter that would disagree with you. After a light dusting, the greens are slightly faster than before because a smoother surface is achieved.

I could probably list 3 or 4 more reasons, but I think you get the idea. A little sand every few days keeps the pathologist away.