Saturday, 1 April 2017

Promoting Bentgrass Grain

Why the hell would you want to do that? You can search the internet for reasons to promote bentgrass grain and I assure you, you won't find much. This is no April Fools joke.

In the world of promoting bentgrass over poa there are a ton of strategies that superintendents use. From managing moisture, to reduced fertilizer and pesticides, to practicing the disturbance theory and allowing the poa to die in winter, it seems that if you want to be successful with bentgrass management you need to do it all.
Coarse, grainy bentgrass growing over top of, and shading out the poa.
One of the tools that supers in the States can use that we can't use in Canada are the growth regulators that hurt poa but not bentgrass. So that approach simply isn't feasible for us up north.

There are many differences between how poa and creeping bentgrass grow. Poa is upright, compact and very dense. Bentgrass grows laterally, has a thicker leaf blade, and although newer varieties are a lot more dense, they still have nothing on poa annua when it comes to density.
While this is a bit excessive, at certain times of the year it could give the bentgrass a huge advantage.
To me, when I look at how bentgrass differs from poa on my putting greens the lateral growth stands out to me. Bentgrass likes to lay down along the surface and in the process it covers up the poa. To me, this is a huge competitive advantage that I think turf managers can capitalize on to promote bentgrass over poa annua.
Bentgrass seeded last fall could be more competitive if allowed to grow laterally.
There is a huge hate on bentgrass lateral growth. Cultural practices such as verticutting, grooming and brushing are all used to stand the bentgrass plant up so that it can be cut shorter and hopefully reduce the lateral growth characteristic of the bentgrass. This can improve putting green smoothness and speed....apparently.

So I wonder, if we can use the natural growth characteristic of bentgrass to give it an edge over poa annua without impacting the way your greens play in a negative way.

Bentgrass seeded last fall growing up around dimple holes to get more bentgrass seed into the profile.

I haven't verticut, groomed or brushed my greens in years and during this time I have seen bentgrass totally dominate my greens. Of course I'm doing other things but in my opinion, it is the lack of grain management that has been the result of my success growing bentgrass.
Ignore the dead poa and see the big gains I have made overseeding bentgrass into my greens. Maybe it's so successful due to the grain?

The negatives of excessive grain to me have mainly been when golfers drag their feet and it stands the grass up in little tufts. Not good.
When golfers drag their feet it stands the bentgrass up which makes the greens bumpy.
So I think that if we are to use grain to our advantage we should only do it at certain times of the year, when poa is strongest. Times like early spring, and late fall are times where I think letting the bentgrass get grainy could allow the bentgrass to out-compete the poa.
Could bentgrass grain give it an advantage over moss too?
So if some grain is good, how do we make more? Essentially, do the opposite of what is done to reduce grain. To reduce grain we stand the grass up, then cut it. To promote grain, we could roll the grass, lay it down, before we mow it.

This is something that I have been doing this spring as my poa is either weak, or dead from a harsh winter. HOC is high because we are establishing new grass from seed and we have little play so there is literally no issue with excess grain on my greens.
More bentgrass seeded last fall into aeration holes. 
I think that promoting grain could also help with establishment of bentgrass from seed. The problem with trying to inter-seed bentgrass into poa is that the poa is just so damn dense. If we can allow the bentgrass to grow above the poa, then lay it down before we mow it, it should have a better chance of out-competing the poa. Of course, we can't let it get excessive. What I'm saying is that maybe some grain is probably a good thing.

Cutting it off short, or grooming it before mowing it only forces bentgrass to compete with poa where it is strongest. If you want to shift the odds in bentgrass's favour, you need to allow it to compete where it is strongest, with its wide, lateral leaf blades that shade the fine upright poa below.