GP is a number. It's explained here in photos and words.

Every now and then I get some questions about the temperature-based growth potential (GP). The most recent question was about relative humidity: “I am curious about the effect relative humidity has on growth potential?

No matter how much sodium one puts into a sand rootzone, the soil structure cannot be affected, so gypsum won’t be required

I received this question about leaching salts from the rootzone: “I remember talking to you once before regarding flushing excess salts from the root zone and the application of gypsum or other calcium products before the flush and you telling me it was not necessary.

How much N is in rain and snow?

I was having a discussion about this last week. “I think it is a tiny amount,” I said, “although sometimes I hear really large amounts when people tell me how much N comes in rain.

MacKenzie's fundamental principle of greenkeeping

I taught two seminars at the 2017 Philippine Golf Course Management conference. One was about MLSN after 5 years. I explained what soil test interpretation is, why the MLSN guidelines were developed, and explained how they work.

If you want to do a 3 million dollar irrigation system, you don’t call me

As a follow-up to part 1 of this extraordinary interview with Don Mahaffey on Golf Club Atlas, here’s part 2. Don knows the golf and grass-growing business from the ground up, and he knows what he is talking about.

Hitting all of our goals

This is an extraordinarily good video about grasses, mowing, construction, irrigation, soils, playability, maintenance cost, and more. If you are interested in these topics, watch this interview with Don Mahaffey.

Summertime syringing to cool bentgrass greens: I wouldn’t do it today

@asianturfgrass many Japanese greenkeepers believe that syringing is effective to keep or lower leaf temperature. How do you think about it? — H.I.GK (@fc3s_13b) May 5, 2013 This question about lowering leaf temperature prompted an extensive discussion about the effectiveness of syringing greens.

For irrigation, which is better? Deep and infrequent, or light and frequent?

That’s a bit of a trick question, because the answer I give is: neither. What one wants to do is apply the optimum amount of water to the turf, and that can be done by light and frequent irrigation, or it can be done by deep and infrequent irrigation.