First find your local county extension office. Tell the extension agent you want to do a soil test which is usually free of charge. He will tell you about the various types of soil test. You can now start collecting your soil samples. To do this test you will need a soil probe or a narrow spade, a clean 5 to 10 gallon container or a clean box, and a zip-lock bag.
It is best to do a soil test from late spring until late fall. This is necessary if you are testing for nematodes as they are within the top 8 inches of top soil at that time of year. The soil should also be moist.
Take the probe or spade and penetrate the soil to a depth of six to ten inches and .collect samples from six to ten locations through out the planting area. After all samples have been placed in the container, mix all the soil completely. Next, take one or two pints of soil and put it in the zip-lock bag. Keep your soil sample out of direct sunlight or extreme heat. Do not allow soil to dry out, or freeze. Take the sample to the county extension office as soon as possible
Hint: try to take your soil samples on a Monday so there is no delay in transporting them to the lab. The test results will normally be sent back to you within two to three weeks.