The more you know about your soil, the better. If you know what kind of soil you have, you can make better decisions about how to keep your lawn and garden healthy. These FAQs should help you get started.
- Why is soil important?
- What is a soil test?
- Why should I test my soil?
- What will a soil test tell me?
- When and how should I test my soil?
- How do I collect a soil sample?
- Can you show me how to do it?
- I got my soil tested. Now what?
Healthy soils are essential for healthy plant growth, human nutrition, and water filtration. Healthy soil supports a landscape that is more resilient to the impacts of drought, flood, or fire. Soil helps to regulate the Earth’s climate and stores more carbon than all of the world’s forests combined. Healthy soils are fundamental to our survival.
A soil test is an easy and inexpensive way to determine your soil’s level of nutrients, pH, and organic matter. Testing your soil is an essential step for a natural approach to lawn care. There is no way to know what your lawn needs without one!
Healthy soil is the key to having a lush, green lawn. It is impossible to know what your soil needs without doing a soil test. Levels of pH, nutrients, and organic matter all impact plant growth.
A soil test will save you time and money by showing you what your soil needs.
Levels of nutrients including phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)
Amount of organic matter
If there is lead contamination
Fertilizer and lime needs
Test results will help you decide what your lawn needs. For example, nutrient levels that are too low will slow plant growth, and levels that are too high can pollute our waterways and may inhibit plant growth. Low pH means acidic conditions and high pH indicates alkaline conditions. If the pH is too high, your grass cannot properly absorb nutrients. Ideal pH should be between 6.5-7.0, slightly acidic. Adding compost can naturally correct your pH.
A soil test should be done at least every three years and before you decide to add any fertilizer or lime to your lawn. The ideal time of year to test your soil is mid to late spring or early fall. Free soil test kits are available from the South Portland’s Sustainability Office located on the first floor of City Hall (the testing will cost $15). You can also get a free soil test kit from the UMaine Extension Office in Falmouth, or you can order one online .
Using a clean spade or trowel, take several samples in different locations on your lawn. Try to remove any large leaves, roots, and sticks from your sample.
Mix the samples in a clean container.
Label the sample box with your name, address, and sample identification (e.g. front lawn) and fill with soil. If you are sending multiple samples, each must be placed in a separate sample box.
Complete the form that came with your soil kit (Note: the crop code for existing lawns is 201; the crop code for new lawns is 211). The form will accommodate up to 10 samples. Remove the top copy and send to the lab with your sample; keep the remaining copies for your records.
Place the sample box(es), form, and payment in a mailing container and send it to the soil testing service at the address on the form. Your results should arrive in two to three weeks.
In this video from the University of Maine Cooperative Extension, you can learn how to sample your soil, when the best time is to test your soil, and where to send your soil for analysis.
When you get your test results back, the results will include recommendations on how to improve your soil. To help you understand your results, the Maine Soil Testing Service offers “Interpreting Soil Test Results for Gardens and Grounds.” If you have more questions about your soil analysis, ask your local nursery or hardware store to interpret the results.