Tuesday, 14 July 2015

When is the best time to water greens?

Nice contrast
I was always taught that the best time to water greens was right before the greens mowers went out. The theory was that this would reduce the time that the plant was wet and would therefore result in less disease. So from my start in the turf industry this is what I did. I am very focused on reducing my reliance on pesticides to control disease so whatever I can do to accomplish this goal, I try.

I was inspired by a post by Dr. Micah Woods a few years ago questioning the deep and infrequent irrigation regime vs the light and frequent. He made a great case that light and frequent isn't necessarily an inferior way to water. The great thing about this way of thinking is that it left me knowing that my way of irrigating wasn't inferior. It also got me questioning a lot of things about irrigation that weren't necessarily true.

This year while I was setting up our irrigation system I started to think about the timing of when I watered greens. I was thinking about the way we have always done it and it just plain didn't make any sense to me. If you have ever been on the course as the sun is setting you will know that the turf becomes covered in dew and guttation fluid. So basically every night that it wasn't raining, the grass was covered in stagnant sugary liquid anyway. So from a leaf wettness standpoint, there was no benefit to watering last. If anything, waiting until the last minute to irrigate the greens only extended the time that the dew and guttation stood undisturbed on the leaf surface. This is a problem if you believe that dew can lead to increased disease.
Too green for my liking despite using half as much nitrogen this year as in previous years.
So then I thought about what the advantages of watering greens first before anything else would be. What would be the advantage of watering greens just as the sun was going down, or at midnight? Theoretically it would knock the dew off the leaf blade and break the stagnation. This stagnation or still water is probably what leads to disease. At least it sounds good in theory.

It would also leave the surface of the greens less wet when we were mowing. Less water pickup into the baskets and less wear from driving equipment on freshly watered turf. Theoretically it would also give the water more time to move down into the soil before being used by the plants. If this water has more time to flow into the soil it also should give me more accurate readings on my moisture meter too. Lots of theories haha!

It would also give the plant the water it required sooner, reducing the time that the plant was in a moisture deficit. Apparently I'm not the only one who thinks this way.

Maintaining the greens has been carefree and almost easy despite record breaking drought, heat and a
mostly broken irrigation system.
So this year I have scheduled my greens to be watered first each night. The result? Well this trial has been far from scientific but I can share my experience. The greens are still alive. I haven't required a fungicide application since we started irrigating in early May except for my regular phosphite apps. Despite going through a record breaking heatwave and drought period the greens have never been better! Is it because of the time of night that I water greens? Maybe. It certainly hasn't hurt things and if anything it has only made things easier.