James Smith said: Ok this is all new to me. I have been using primo on my greens for13 years spraying about every 3 weeks. what is a GDD?
Randini,
Even though I've got Red fooled, I'll throw my 2 cents in and guess the answer your question. GDD is "Growing Degree Days" It's some mumbo jumbo of taking the high and low temperatures or average temperature and assigning it a number. (I know it's used to track poa seedhead development, and in some cases when to apply pre-emergent herbicides and I think it's used a lot in agriculture). When those numbers add up to 200 as for Primo, the Primo stops working and one gets a growth spurt. It continues to have a growth spurt until more Primo can be applied. The bad deal when the grass breaks free from the Primo, in the summer anyway, the plant needs a ton of carbs for the growth and that will come from the weak root system already hammered because of the summer. The research shows that one is actually better off not using Primo as the growth of the greens are consistent without Primo. (of course there are the other benefits of Primo so I know I will continue to use it, I'm just making sure to stay in my application windows.)
The studies as I understand were conducted at Wisconsin, and the Primo only affected bent grass mowed at greens height. Cool season grasses at tee and fairway height one would just continues to follow the label, it's not affected by GDD's.
As far as warm season grasses, tee and fairway height it is follow the label there as well. As far as warm season greens, I think the label rate is good with that, but I would bet my life on it.
The Growing Degree Days deal only affects greens height cool season grasses I believe.
Red, picked up a Min/Max thermometer from Forestry Supply for pretty cheap (well under $50) it will record up to 5 or 6 days worth of reading, and it will do it in F and C.....funny it always resets to C, too bad the chart couldn't be converted to C. I'm wanting to get a weather station like Andy has but I hate spending the little over $100 for it.
Mel