Soil Testing

Soil testing is the best way to determine the pH of  soil as well the nutritional content for properties that you care for.  This can be a way to troubleshoot problems in the landscape and can also be a value-added service to provide to your customers.

The University of Florida has soil testing labs and there are local ones as well.   We offer two types of test: one for soil pH and recommended liming requirements and one for pH plus soil nutrient availability of Phosphorus, Potassium, Calcium, and Magnesium.  The tests cost $3.00, and $7.00, respectively.  We don’t test for Nitrogen because this nutrient changes chemical forms rapidly in the landscape.

So why might you want to know the pH of the soil?  As pH levels become either more acid or more alkaline, nutrients in the soil become less available to our plants.  The nutrients may be there, but not in the chemical form that your plants can use.  Our pH in south Florida is typically on the high (alkaline) side.  Many of our landscape plants can tolerate a wide range of pH levels, but some are pickier.  Ixora is one example of a plant that is very sensitive to high pH levels. The red, splotchy discoloration on Ixora is the plant’s expression of Phosphorus and Potassium deficiency, induced by pH.

pH-induced Potassium and Phosphorus deficiency on Ixora. UF Laura Sanagorski

These two nutrients are most likely in the soil, but are not in a chemically available form at higher pH levels.  Your options in this case would be to either live with the deficiency or to reduce soil pH by applying sulfur or an amendment such as aluminum sulfate or ammonium sulfate.  However, the best outcome for this situation would have been to choose plants that are happy with the pH – the right plant, right place principle.

Many landscape plants are tolerant of a wide range of pH and nutrient levels.

Potassium deficiency. UF Laura Sanagorski

Palms are very sensitive to nutrient deficiencies.  Potassium (see photo on left) and Magnesium deficiencies are two nutrient problems to which our South Florida palms are very sensitive.  If a property you care for has a lot of palms or you are considering planting species that are sensitive to soil pH levels, you might want to recommend soil testing to your client.

To submit a sample to the University of Florida’s soil testing lab, you can either pick up a test kit here at the Palm Beach County extension office (531 N. Military Trail) or you can download the form at .  This form gives detailed instructions on how to collect a sample.  When you receive you test results, in about a week, I’ll be happy to discuss the report with you.


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