FOR IMMEDIATE RELEASE
WEDNESDAY, JUNE 30, 2004
||Catherine Stokes, information and communications specialist
All planting soils are not created equal
WILMINGTON — Buying "topsoil" is popular these days for everyone from container gardeners to landscapers. The truth is, however, that actual topsoil is rarely available. Products on the market are often manufactured blends—mixtures of soil, sand, compost and other materials. They may look similar, but they can be very different.
Tim Hall, a regional agronomist with the N.C. Department of Agriculture and Consumer Services who deals with soil quality and plant nutrient issues, urges landscapers to test bulk loads of soil mixes, mulches and other soil amendments before using them. He knows about potential problems that untested soil amendments can cause in lawns and landscapes. He has seen lavish and expensive plantings fail because of pH, salt or other problems.
"When you're dealing with soil blends and composite soil amendments, there are a lot of unknowns," Hall said. "Soils are variable to begin with, and once you start mixing in composts, manures and organic matter, it can really get complicated. People often assume that large additions of these materials are always beneficial. While they can improve soil texture, they also change soil chemical properties that can affect plant health. You need a proper analysis of the material to know how best to use it."
Waste analysis, which is similar to soil testing, is the appropriate test for composted materials, animal manures and sand/soil/organic mixes. Unlike soil tests, waste analyses measure different types of available nitrogen. They also provide information that helps people decide whether additional lime or fertilizer is needed.
Hackney Parker of Seaside Mulch in Wilmington has been selling composted manures, bark potting media and other special soil mixes for more than eight years. His customers—usually landscape architects—trust him to provide consistent, reliable products. Parker lives up to that expectation, in large part, because he has his soil mixes and composts analyzed.
“Seaside’s topsoil blend is a good example of how our waste analysis helps the landscape industry serve their customers,” Hall said. “Seaside aims for confidence in their product. It would be great for the industry if every supplier tested their mulch and soil products.”
Parker sends samples of his products to the NCDA&CS waste analysis laboratory and receives a detailed report about each product. This information is passed along to his customers. They leave Seaside Mulch with specific knowledge about the planting mix they have purchased—its pH, nutrient content and level of soluble salts.
"I think it's important to be able to give chemical test results to my customers," Parker said. "If they know the analysis, they can add the right amount of lime and fertilizer. I'm surprised that more retail customers don't request this information."
Parker also keeps informational brochures and sampling supplies on hand for anyone who is interested in taking their own soil or waste samples.
You don't have to manage a large landscape operation to benefit from agronomic tests. Anyone who produces enough compost to use in flower beds or vegetable gardens can use waste analysis to identify potential problems and find ways to avoid them. Waste analyses cost only $4 per sample, and results are usually available within two working days. Soil samples are free and results are available in about seven working days in the summer.
Information on how to collect and submit waste and soil samples is available online at www.ncagr.com/agronomi/pubs.htm. For additional help, get in touch with your local NCDA&CS regional agronomist (see www.ncagr.com/agronomi/rahome.htm for contact information). Agronomist Tim Hall is available to provide advice for handling fertilization or nutrient management problems in Duplin, New Hanover, Onslow, Pender and Sampson counties. He can be reached by phone at (910) 324-9924 or by e-mail at firstname.lastname@example.org.