Lime or sulfur can be safely applied to the soil at any time. Work them into the soil before planting or side-dress existing plants. Since soil pH will slowly revert to its original level before treatment, it’s a good idea to test your soil every two years. You can have your soil’s pH measured by a university laboratory through your local cooperative-extension service or use a soil testing kit from garden stores or catalogs. The lab test report or kit instructions will give suggestions on how to raise or lower soil pH. Lab reports will list your soil’s resistance to pH changes based on the structure of your soil. This is referred to your soil’s buffer pH. If your soil is sandy and well drained you can raise the pH a full point in one season. Heavy clay soils will take more lime and a longer time for the same amount of change in the pH level.
For the best plant growth and health of your gardens a soil test for the major and micronutients available should be made every 3-5 years. This will allow you to balance your fertilizing program to suit your plants individual needs according to your soil instead of guessing. It is important to collect the soil samples properly, keeping the results pure.
The soil needs to be dry when collecting the samples. With the standard test you need to collect the soil from 6-8 inches deep. This will test for nitrogen, phosphorus, potassium and the pH of the soil. A nitrogen profile test is done with a sample taken at 24 inches. This will tell you about your nitrogen and micronutrient levels in detail. Make sure not to mix the upper level sample with the deeper ones. Take sample from 6 or 7 locations in the same general garden area. If you have several different gardens take a group of samples from each area and do a separate test. All gardens have microclimates and a varying degree of nutrient levels. Take the 7 different samplings from an area and mix together in a plastic bag. Place one cup of the mixture into a paper bag. Clearly label the bags so you know which garden it represents.
Soil pH Tester Kit
Liquid formula to test the soil pH easy to use accurate liquid testing contains enough for 20 tests.
Garden Soil TestKit. 4 Separate Tests (pH, Nitrogen, Phosphorus, Potassium)