Turfgrass soil sampling, part 5 of 7

I’d read the soil sampling instructions from Penn State and Rutgers, suggesting a minimum of 12 subsamples be combined as a composite sample for each area. When I give instructions for sampling, I suggest a minimum of 5 subsamples be collected per green (or per area). And the Donohue article I’ve written about suggests 20 samples be collected from an area about the size of 4 typical putting greens.

Tifdwarf green at Southern Links, Okinawa The standard recommendation for turfgrass seems to be a minimum of 12 samples for an area the size of a golf course putting green.

I wondered what other people do, so I sent out this poll on Twitter, asking “When collecting samples for soil nutrient analysis on golf course putting greens, how many subsamples do you collect to make a single composite sample for one putting green?”

The results, excluding those who answered the survey just to see results, came to a total of 182 respondents.

Percent of poll respondents collecting this number of subsamples per green to make a composite sample.

1 to 512%
6 to 1045%
11 or more43%

It seems a lot of turfgrass managers are following the standard recommendations of at least 12 subsamples per area, althought more than half the respondents are collecting fewer than the recommendation of 12. I was surprised there were so few respondents collecting 5 or less subsamples—I would have thought more people would do this the fast and easy way.

Micah Woods
Micah Woods

Scientist, author, consultant, and founder of the Asian Turfgrass Center