pH

You’ve see the photos from Doug Soldat with the striking effect of potassium on snow mold, haven’t you? He joined me on the ATC Doublecut to talk about that. At the end of the show, I brought up soil pH charts, and we discussed the common one that I don’t like, and don’t use, starting at about the 46:20 time in this video.

Have you heard about the Park Grass experiment? The one that started in 1856 with different fertilizer treatments applied to a hay meadow in England, with those fertilizer treatments applied year after year to see what happened to hay yields?

I recommend annual soil testing of professionally-managed turfgrass grown on sand rootzones. For turf growing in soil, I don’t mind testing every two or three years. But sand rootzones usually aren’t very well buffered and important soil properties can change rapidly.

I was reading the “Cultural Aspects of Disease Management” chapter in Management of Turfgrass Diseases by Dr. Vargas and came across this gem about soil pH: “Most of the literature tells you that the soil pH should be maintained at the optimum level for turfgrass growth (between 6 and 7).

I almost always recommend keeping the soil pH above 5.5. This minimizes soluble aluminum in the soil, which can be toxic to roots. Get the soil pH above 5.5, and the soluble aluminum won’t be very soluble anymore—it drops almost to 0.

I saw a list of proposed topics for an upcoming turfgrass conference, and under the heading of soil fertility was included base saturation. I immediately thought of this paragraph from Murray McBride’s Environmental Chemistry of Soils:

Even though high quality turfgrass can be produced below a soil pH of 5.5, for standard situations I will recommend keeping soil pH at 5.5 or above. Soluble aluminum will be negligible above pH 5.

I did an experiment in a greenhouse in which I grew creeping bentgrass in four different sands. I collected all the clippings and measured what was in them. And I tested the pH of the sands, and I did soil tests to measure the soil nutrient content.

I read a post on the Golfdom Daily about soil pH in which it was suggested that it was important to maintain soil pH in the range from 6.5 to 7.