Testing Your Soil Chemistry

It’s that time of year again, for Sarasota area homeowner’s to consider preparing their lawn and garden for the growing season.

Every gardener wants to do everything they can to cultivate healthy plants and a luxurious yard. Once you meet the sun, soil type, and water requirements for your plants, you should also consider testing your soil for nutrient and pH levels. Testing is especially important when you mix your own growing media. The information you get from soil tests will help guide you to grow the healthiest plants possible.

soil testing

Soil chemistry testing can provide information about different properties that affect your plants’ growth.

Nutrient levels: A soil chemistry test can tell you the levels of important nutrients including phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). Phosphorus acts as a building block for strength and growth in plants. Potassium contributes to important processes like the uptake of water and production of energy during photosynthesis. Calcium strengthens cell walls, and magnesium powers the conversion of sunlight by contributing to the green pigmentation in chlorophyll. A deficiency in any of these nutrients will result in a small, weak, unproductive plant. The test will tell you whether your soil has a deficiency and help inform your calculations for how much fertilizer to apply to correct the nutrient levels.

Percentage of organic matter: Organic matter (living or dead plant and animal matter, decomposed materials, etc.)  is an important component of soil composition. It helps maintain a stable pH, provides a consistent supply of nutrients, and feeds beneficial microbes and soil fauna. The range of organic matter in our Florida soils is usually 1-5% of the total volume of soil. For healthy soil, aim to have organic matter levels between 3-5%.

pH: A soil test will tell you the pH (the acidity or alkalinity) of your soil. pH ranges from 1 (extremely acidic) to 14 (extremely alkaline), with 7 being a neutral pH. Most plants in our area grow best in relatively neutral soil between 5.5-7. Knowing the pH will help you determine whether you need to add lime, which will raise the pH, or if you need to add a sulfur compound to lower it. Our sandy Florida soils are naturally acidic, so liming is much more common than sulfur treatments. Some soil tests will provide the exact lime requirements your soil needs to reach a healthy pH.

There are two main ways to test your soil. The most accurate method is to collect a sample from your garden and send it to a professional laboratory. Though this may sound complicated, soil tests are inexpensive–organizations like local county extension offices or the University of Florida can perform soil chemistry tests for less than $10. If you would rather not send a soil sample to a laboratory, there are a variety of at-home soil test kits available for around $20-50. The results may not be as accurate as laboratory testing, but they will still identify major issues. These test kits are simple and use a variety of methods. Some are capsules, some utilize liquid droppers, and others are probes stuck directly into the soil.

Whichever method you choose, we highly encourage testing your soil. Visit the online Big Earth Landscape Supply store and browse our selection of quality fertilizers, compost, and lime products to achieve the healthiest yard possible.