The 2019 Master Gardener class, plus Pete (center blue cap) demonstrate soil sampling.

To lime, or not, that is the question

I’ll be first to admit gardening is hard work. Over the years, the man of the mower has put in sweat and toiled to draw forth an edible bounty. Working the land has revealed a great deal about previous land use. Charred wood, metal farm implements and building debris have been unearthed in random areas. As a result, we test for pH and plant available nutrients before any work is done. Soil testing is appropriate to determine if soil fertility levels (and pH) are adequate for vegetables.

The above is one example of “many hands make light work.” Swapping vegetables, plants and seeds is a side-benefit.

Avoid sampling –

Previous burn pit/areas where fireplace ashes are routinely dumped
Low-lying areas that hold water
‘Bad’ spots where “nothing seems to grow” should be sampled separately

Download and print UF’s Landscape and Vegetable Garden Test Form.  Collect 10-15 sub-samples in zig-zag pattern. For vegetable garden, collect soil from surface to a depth of six (6) inches. Ninety (90) is the vegetable crop code.

What’s the difference between Test A and Test B?

Test A ($3 per sample bag) only provides soil pH and lime, if needed. Test A will not indicate levels of phosphorous, potassium, calcium and magnesium present based on your sample. It will not provide recommendations for nitrogen, phosphorous and potassium.

Test B ($ 7 per sample bag)  provides pH, and amount of phosphorous, potassium, calcium and magnesium available for growing plants. Based on the sample and crop needs Test B will list pounds of lime, nitrogen, phosphorous and potassium to apply.

illustration of soil sample results with additional potassium recommended

Soil sample Test B report.


“Application of lime when it is not needed may cause plant nutritional problems.”  EDIS document SP 103, revised May 2018

Soil testing is NOT appropriate when vegetables are performing poorly because they are not adapted to the site (insufficient hours of direct sunlight). Contact the local extension office for interpretation of soil sample results. UF’s Florida Vegetable Gardening Guide offers resources and information for novice and experienced gardeners.  Until next time – Happy Gardening! 

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