Before you invest $10 in a soil test, remember the following: A soil test rarely reveals the sole cause of decline or death in trees and shrubs. In the vast majority of cases, problems with trees and shrubs are due to disease, insects, herbicide damage or poor growing conditions. Examples of poor growing conditions are too wet, too dry, poor drainage, planted in the wrong location (shade plant in sunny area), etc. Even without a soil test, you can confidently fertilize trees and shrubs with a coated time release fertilizer such as OSMOCOTE (tm) 14-14-14 each spring (April or May) at the rate of 1.5 to 2 pounds per 100 square feet under and around plants. To help diagnose problems, we have trained Master Gardeners on staff. They can provide you with valuable information on growing trees, shrubs, lawns and gardens in this area. They are on duty Monday through Friday 9 a.m. to 4 p.m. and can be reached at 918-746-3701 or 918-746-5130.   A soil test will provide the pH, N-P-K (nitrogen, phosphorous and potassium levels) of the soil. If you have recently fertilized, you must wait two months before collecting a soil sample for a test. It is very important how a soil sample is collected and brought into the office so please follow the instructions below. INSTRUCTIONS FOR TAKING A SOIL SAMPLE Do not take the top 2 inches of soil. Go down 3 to 6 inches to get soil. Take samples from 5 or more random areas (more for a bigger area) zig-zagging across. Take a cup of soil from each of these areas. Mix all samples together in a clean container. Take 1 pint of soil from the mixture to bring in. Soil must be DRY, with no rocks , sticks or grass in the sample. Soil tests are $10 each. It takes 2 to 3 weeks to get the results back.   Bring soil samples to the OSU Extension Center, 4116 E. 15th St., (on 15th, between Harvard and Yale) or call 918-746-3701 for more information. Top Oklahoma Cooperative Extension Service The information given herein is for educational purposes only. References made to commercial products or trade names is with the understanding that no discrimination is intended and no endorsement is implied.