Soil sampling basics
Soil sampling can be one of the best and most economical resources for people growing anything in soil. At the same time, soil testing may be a resource that is the most underutilized by individuals also.
When soil samples are taken correctly, mixed and submitted to the UGA Soil Test Lab in Athens, the resulting recommendations can be a major help in developing and maintaining a productive soil. It is true that many of our UGA publications will give basic liming and fertilizing recommendations, but a properly completed soil sampling procedure will give you specific guidelines for your soil.
A soil test can take out the guess work in liming and fertilizing and hopefully provide better growing results. Today, I will be sharing information from a UGA pamphlet on soil testing by Leticia Sonon and David Kissel, UGA Agricultural and Environmental Services Laboratories. Before I get into the actual soil sampling procedure, I will share soil sample submission information.
First, due to COVID, we do have a soil sampling station in the lobby of the Gordon County Agricultural Service Center with soil sampling kits. The Gordon County Extension Office is open fully for business so we can assist face to face. To send a soil test to the UGA Soil Test Lab, the charge here is $9 per sampling procedure or soil sample bag. This includes postage since we provide the shipping of the sample. We even have soil probes that can be checked out by clientele to make sample collect easier.
Please note that we do not come out and collect the soil samples for you. If you choose, I can email the directions on how to collect samples or verbally walk you through the process by phone if you have additional questions. Soil test results should be posted in five to six working days and we can either email or mail you the results.
When and how often should soils be tested? Soils can be tested any time during the year. In fact, we normally are submitting soil samples to the lab weekly. There are times of the year, we do seem to have more sampling take place. We do recommend for a client to allow enough time for the soil analysis and for lime and fertilizer application. We tend to live in an area where soil pH can be lower.
This means that many times soil reports will include a liming recommendation to improve soil pH. Lime reacts slowly and will need to be applied or mixed with the soil two to three months before planting.
Fall can be a great time to take soil samples because it can be drier and areas are more accessible. Once medium or high fertility levels are established, it is recommended that lawn and ornamental areas need to be sampled every two to three years. Vegetable gardens should be sample every one to two years.
Keep in mind that you can soil sample for almost every type of soil growing activity. The most common soil sampling done are for lawns, vegetable gardens, pastures, hayfields, cropland and ornamental plant areas. The big key is to know the correct sampling depth for soil collect. This is based on the type of plants being grown. For example, for lawn, hayfields and pastures, sample to a depth of 4 inches.
For gardens, ornamental, mixed fruit trees and wildlife plots, sample to a depth of 6 inches. When you collect samples for mixing, you use a zig zag approach to randomly stop and collect samples.
Many times, you will collect ten samples for mixing. For trees and shrubs, take soil samples from six to eight spots around the dripline of the plants. Keep in mind that if you are sampling large acreage such as a pasture, a sampling procedure is to represent no more than approximately 15 acres so you may have to divide the acreage up and conduct multiple sampling efforts. Remember to number or name those different plots so you can keep the samples separate and know which soil report goes with what spot on the farm. We will also code the samples being shipped for that growing activity to obtain specific recommendations based off that growing activity.
When collecting samples, you will need a plastic container for putting the samples in and use that container for mixing the samples. You will need a collect tool for taking the samples such as a trowel, shovel, spade or probe. Again, we have probes that can be checked out for collection ease. Remember you are collecting samples in a random zig zag pattern and you randomly stop ten times.
When you stop, clear the ground surface of grass thatch or mulch. If you are using a trowel for example, push the tool down in the soil to the desired depth. Push the handle forward, with the spade still in the ground to make a wide opening. Then, cut a thin slice from the side opening that is of uniform thickness, approximately 1⁄4 inch thick and 2 inches wide, extending from the top of the ground to the depth of the cut. Put the sample in the container and then move to the next spot. Each sample for that specific procedure will go into the container. When the samples are all taken, mix the soil in the container.
We will need one pint of the mixed soil for shipping to the UGA Soils Test Lab.