The amount of fertilizer to apply to a garden depends on the natural fertility of the soil, the amount of organic matter present, the type of fertilizer used, and the crop being grown. The best way to determine fertilizer needs is to have the soil tested. Soil testing is available through your local Extension agent, through private labs, and with soil test kits which can be purchased from garden shops and catalogs.

This publication explains how to obtain representative soil samples and to submit them for analysis to the Virginia Tech Soil Testing Laboratory.