How to take a soil sample
Beneficial results of a soil test depend on a good sample. The sample should represent the area it is taken from. A soil sample must be taken at the right time and in the right way. The tools used, area sampled, depth and uniformity of the sample, information provided, and packaging all influence the quality of the sample. Correct Sampling Time: Take a soil sample a few months before initiating any new landscaping—whether it be laying sod, starting a vegetable garden, putting in a flower bed, or planting perennials. This way, if the soil test report recommends lime, you will have enough time to apply it and have it adjust the soil pH before you plant. Sample established areas—lawns, trees, shrubbery, and other perennials—once every three or four years. You can sample at any time of year; however, mid-August through mid-September is an ideal time to take samples for cool-season grasses, such as fescue, bluegrass, and ryegrass. By sampling at this time, you can be ready to apply lime in the fall. If an established area exhibits abnormal growth or plant discoloration, take a soil sample right away. You may want to submit matching plant tissue samples or separate soil samples for nematode assay. For areas recently limed or fertilized, delay sampling at least six to eight weeks. Use Clean Sampling Equipment: Use a soil-sampling probe, an auger, a spade or shovel. Tools should be either stainless steel or chrome-plated. Do not use brass, bronze, or galvanized tools because they will contaminate samples with copper and/or zinc. If a shovel or a spade is used, dig a V-shaped hole to sample depth (4-6’’), then cut a thin slice as shown on the right. Mix soil cores for each sample in a clean, plastic bucket. If the bucket has been used to hold fertilizer or other chemicals, wash it thoroughly before using it for soil samples. Sampling Area: Each sample should represent only one soil type or area—for example, a lawn, vegetable garden or perennially landscaped area. For each unique area, take at least six to eight samples. Place all the samples for one unique area in a plastic bucket and mix thoroughly. Use the mixture in the bucket to fill a soil sample bag about two-thirds full. Look for the fill line on the bag. If one area of your yard seems healthy and another has bare or yellow areas, sample healthy and unhealthy areas separately even if both are lawn grasses or flower gardens, etc. Sampling Depth: For lawns, sample to a depth of four inches, excluding any turf thatch. For vegetable and flower gardens, sample to the depth that you plan to incorporate lime or fertilizer, usually four to six inches. For shrubbery, remove any mulch or surface debris, then sample to a depth of four to six inches around the base of plants. Avoid zones where lime or fertilizer has been recently applied. Submitting Samples: Put samples in A&L sample bags or medium zip-lock bags. Use a ballpoint pen or water proved marker to label each sample bag and complete the soil submittal form. Do not use felt tip pens since most of them do not contain waterproof ink. Bags labeled with a pencil can be very difficult to read if they become dirty. List the crop code shown on the back of the information sheet in the appropriate column. Do not put information sheets inside sample bags. Attach information sheets to the outside of the shipping bag or put them inside the shipping box next to or on top of the samples. Do not use sample bags as mailing containers. Samples should be shipped in a sturdy, corrugated cardboard box.