Most growers take soil samples this time of year for reliable results and because it’s a good time to adjust pH if necessary. This is important for farms as well as home gardeners. It can tell you a lot about what your plants might need. UMass Extension Vegetable Program recently sent out helpful instructions on how to properly take soil samples:
Avoid sampling when the soil is very wet or soon after a lime or fertilizer application. If a field is uniform, a single composite sample is sufficient. A composite sample consists of 10 to 20 sub-samples taken from around the field that are then mixed together. To obtain sub-samples, you can use a spade to take thin slices of soil representing the top 6 to 8” of soil. A soil probe is faster and more convenient to use than a spade and is worth the small investment if you have many fields to sample. Remove any thatch or other organic material such as manure from the surface before taking your sample, as this will result in inaccurate soil organic matter levels. Put the slices or cores into a clean container and thoroughly mix. Take about one cup of the mixture, spread it out on paper to dry overnight at room temperature, and put it in a zip lock bag. Samples do not need to be fully dry to submit, but drying them overnight will speed up the process at the lab.
They also mention the following: “Soils should be tested for nutrient levels and organic matter content every two or three years, unless a specific soil management process needs to be evaluated sooner. Organic matter testing is not included in routine UMass Soil Lab tests, so be sure to check the box on the sample submission form if you want organic matter results. A routine soil test at the UMass Soil Lab costs $20; organic matter is an additional $6.”
Anyone can send tests to the UMass Soil Lab, but make sure you fill out the proper form. Home growers should fill out the Home Grounds and Gardening Form found here. This way the results and the suggested amendments you receive will be on a smaller scale and make sense for your space.
What the lab is actually testing for? UMass Extension says, “A routine soil test includes phosphorus, potassium, calcium, magnesium, and sulfur, as well as micronutrients. At UMass, the routine test automatically includes pH, but does not include nitrate or organic matter; these additional parameters can be requested as add-ons to the routine test. If the crop is indicated on the submission form, routine soil test results will inform how much of what type of fertilizer or soil amendment you should add to a field for that crop the following season, based on that crop’s nutrient needs and the soil test results.”
We took soil samples in several locations around the farm last week and will send them in soon. We will get results for all our vegetable fields, the blueberries, the raspberries, the greenhouses where we grow tomatoes, the tea garden, and an area where we may plant more fruit trees. More on that later!
Until next time,
Ember