Now is a good time to start prepping your landscape and vegetable gardens for plants.

The best place to start is by finding out your soil composition. If you understand the nutritional composition and condition of your soil, you will be a more successful gardener.

You don't have to get your soil tested, but a test can tell you a lot about what’s going on where your plants live.

Soil provides essential nutrients, water and oxygen, which are needed, along with sun and air, for your plants to thrive.

The best garden soil should have a proper balance of minerals, water, organic matter and air.

A good soil has a balanced mixture of clay, organic matter and sand, each of which has different particle sizes.

Sand has the largest particles, while clay has the smallest. Silt falls somewhere in between.

Sand, silt and clay determine soil texture, but it is the organic materials consisting of microbes, fungi and decayed plant matter that improve soil structure. An ideal soil is composed of about 45% minerals (gravel, sand, silt or clay), 25% water, 25% air and 2% to 5% organic matter.

Nutrients come from the organic matter in the soil. Decayed plant materials contain carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, calcium and magnesium, as well as other nutrients in smaller amounts. All of these nutrients are key to soil fertility and plant health.

Microorganisms also are an active organic portion of soils, making up 10% to 40% of the organic matter. This is in addition to about 40% to 60% of humus, which is a stable form of organic matter.

The LSU AgCenter Soil Testing and Plant Analysis Lab can tell you all about your soil. Soil sample kits can be found at many local retail nurseries and at AgCenter offices.

In addition to providing the composition of your soil, the lab will make recommendations on how to optimize it by providing valuable feedback on fertilizer and pH.

The pH indicates the acidity or alkalinity of your soil. Plants actually prefer a slightly acidic soil at a pH of around 6.5. At the correct pH, your plant will have the optimum availability of soil nutrients. If your soil pH is off, plants may not be able to use some nutrients.

To adjust soil pH, use acidifying fertilizers or lime. For more information on soil pH and how to adjust it, go to LSUAgCenter.com and search for the “Louisiana Home Lawn Series: Soil pH” publication.

Soils that lack nutrients can be improved by adding organic matter, commonly referred to as soil amendments. Amendments are mixed into the topsoil to improve soil texture and nutrient content.

You can use no-cost or low-cost amendments such as locally sourced manure, compost and compost tea, leaves, grass clippings and your kitchen scraps.

Here's some common soil amendments that can be found at local nurseries or garden centers: compost, peat moss, mycorrhizae, topsoil, composted manure, worm castings, wood ashes, mushroom compost and biochar.

In general, soils high in organic matter will retain more moisture, have improved drainage and aeration (oxygen), resist compaction and have higher levels of nutrients that improve plant growth.

Fertilizers also can be used to improve nutrient content in the soil. However, take care when using them. It is important to apply fertilizers at the proper rate following the label instructions to prevent runoff into surface waters such as bayous, swamps, rivers, ponds, lakes and streams.

To get a quick idea of what type of soil is in your area, you can download the SoilWeb app on your smartphone. Follow the directions to “get my location,” and GPS coordinates will give you a report on the type of soil in your area and its components.

For more information on your soil type, consult the Natural Resources Conservation Service website at soils.usda.gov, or go to the LSU AgCenter website and search for “An Update of the Field Guide to Louisiana Soil Classification.”


Email questions to gardennews@agcenter.lsu.edu.