Turfgrass soil sampling, part 5 of 7
An informal survey about the number of subsamples collected to make a single composite sample
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.
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.
| Subsamples | Percent |
|---|---|
| 1 to 5 | 12% |
| 6 to 10 | 45% |
| 11 or more | 43% |
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.