How to Garden with Phosphorus

Test your soil for the available mineral nutrition and the pH balance. Call your county extension office and ask them for the name and address of the testing lab they recommend. For a small fee, the lab will return a complete analysis of your soil, which is important to knowing how much, if any, phosphorus you need.

Amend your pH balance if the test results recommend it. Too low or too high of a pH will not allow the plants to benefit from the phosphorus even if the correct amount is in the soil. Adding lime to the soil will raise the pH, and adding sulfur will lower it.

Determine what method you want to use to add any necessary phosphorus. Rock dust is available at home and garden stores and will slowly increase the phosphorus. It must be tilled into the garden soil. Animal manure from cows, sheep or horses have high levels of phosphorus along with high levels of nitrogen. The manure can be spread on the garden in the fall, and by spring will be composted and dissolved into the soil.