Written by: Charlotte Glen, Horticulture Agent

Fall is the best time to plant in the southeast, but for plantings to be successful, gardeners must first prepare the soil so it can support healthy plant growth. In Pender County our soils vary considerably, and include nutrient poor, dry sands and heavy, poorly drained clays. Each of these extremes causes problems gardeners must first deal with before they can successfully grow a wide range of plants.   

Sandy soils drain quickly and may not be able to retain the water that plants need to grow. Sandy soils are also less able to hold on to nutrients, causing plants to be stunted or yellow. Poor drainage occurs when water isn’t able to move through the soil, causing pools of water to stand above ground or soils to remain waterlogged for extended periods of time. Waterlogged soils are a common cause of plant death. Roots need oxygen to live but in water logged soils the space once occupied by oxygen is replaced with water, causing roots to literally drown and leading to conditions that encourage root rot diseases. One of the main contributing factors to poor drainage is compaction of the soil from foot, pet and vehicle traffic. Compaction squeezes air out of the soil, leaving less room for water to filter through.

Improving Problem Soils

The most important and easiest thing that can be done to address both of these common soil problems is to incorporate organic matter, such as compost, into your soil. Adding organic matter improves the ability of sandy soils to hold water, helps with drainage in heavy and compacted soils and increases the overall nutrient-retaining capacity of any soil. Composted organic matter can be purchased from garden centers or mulch suppliers or made at home. All that is needed is a supply of leaves, hay, kitchen scraps, grass clippings or other organic materials to start a compost pile. Compost piles that are regularly turned will break down much faster than those that are left to decompose naturally. A pile that is turned weekly should be ready in two to four months depending on weather conditions. Piles that are left on their own can take up to three years to decompose fully. When using compost as a soil amendment, apply three to four inches to the top of the soil of new beds and till in to a depth of six to eight inches, or deeper if possible. In existing beds, compost can be added as a top dressing (a thin layer on the surface) where earthworms, rain and other natural processes will aid its incorporation into the soil over time.  

Know Your pH

Another factor that affects how well plants grow is soil pH. This is the measure of how acidic or basic soil is. Soils in our area range from 3 (very acidic) to 8 (basic), while most plants prefer to grow in a slightly acidic soil with a pH between 5.5 and 6.5. Problems occur when gardeners try to grow plants that prefer a certain pH in soils that are higher or lower than the plant likes. Since pH affects the availability of nutrients to plants, symptoms of pH extremes often show as nutrient deficiencies, such as yellow leaves or stunted growth. Knowing the pH of your soil is the first step in choosing the right plants for your conditions. Soils that have very high or very low pH’s can be improved by adding lime to raise pH or sulfur to lower pH. This should not be done without first determining the exact pH of the soil. The best way to determine your soil’s pH and nutrient needs is to submit a sample to the North Carolina Department of Agriculture, who provide free soil analysis to all North Carolina residents. Sample collection boxes and forms are available from any Cooperative Extension office in North Carolina. Completed samples are shipped to Raleigh for analysis, free from any Extension office and the results, with recommendations, are mailed directly from NCDA to your home address.

Learn More!

Make your own soil amendment by composting your lawn and kitchen scraps! Learn more from this August Pender Gardener article.

Find out more about soil testing from this January Pender Gardener article.

If you would like to know more about soil improvement, composting or need soil sample boxes and forms, drop by the Pender County Cooperative Extension Center at 801 South Walker Street in Burgaw or call us at 259-1235 (office hours: Mon – Fri, 8am – 5pm).