Turning Nursey Plant Waste Material into a Recycled Potting Resource
SEFFNER, Florida – A University of Florida horticulturist is using the power of the sun to turn nursery plant waste material into a recycled potting resource.
Shawn Steed has received a Southern Sustainable Agriculture Research & Education (SSARE) On-Farm Research Grant to determine whether soil solarization is an ideal process of returning plant waste byproduct to the production stream as re-usable potting material in the nursery industry. Soil solarization uses the radiant energy of the sun to create high temperatures to control pests and diseases naturally.
“If the process works, it will reduce the problem producers face with disposing of plant waste, reduce input costs by recycling potting soil, and increase the sustainability of nurseries that use the process,” said Steed, a multi-county environmental horticulture production Extension agent. “There is a tremendous opportunity to recycle used potting media that is accumulating on nursery farms and is not being used productively.”
Steed said that visits to nurseries throughout Florida sparked a need to address the issue of what to do with low quality plant material culled from production, or products that go unsold.
“The plant and the potting material are usually just dumped out of the pot into a pile. As the pile grows, it introduces weeds, pests and other undesirables,” said Steed. He estimates anywhere from two percent to 10 percent of container plants, on average, are dumped each year.
“There is also the sustainability issues of using peat and pine bark as the major components in growing ornamental plants. In recent years, the industry has seen shortages in supply of both materials,” said Steed. “With this project, we are hoping to create a very easy, cost-effective process to turn that nursery waste material into a recycled resource that even a small nursery could utilize to conserve money and resources.”
Soil solarization involves heating the soil by covering it with plastic tarp for several weeks during the hot summer months when the soil receives the most direct sunlight. The process kills pathogens, insect pests, nematodes, and weed seeds and seedlings, and increases soil nutrients and organic matter content making it an ideal product for plant production.
Steed plans to use the technique at two different scales (one cubic yard of material and 3.3 cubic yards of material) representative of grower size, and use the composted material to grow viburnum and crape myrtle, two popular nursery plants in the Southern region.
“We’ll use clear plastic over wasted potting media to raise temperatures. When the adequate temperature and time is reached, we will stop the process and check the product for pests and weeds, and look at some of the basic chemical and physical properties,” said Steed. “We will then use the recycled material in different ratios with new potting media to see how well the viburnum and crape myrtles grow.”
Steed said nursery producers face challenges in dealing with large amounts of unsold products with the downturn in the economy, thereby increasing their dump pile.
“Most growers use pine bark and peat as the majority of media in their container mix, and with the shortages of those products and the increase of waste material on hand, a good solution might be right there on the nursery,” said Steed. “I’m hoping that this research will enable them to recapture some of those lost dollars, while helping them create a more sustainable production system.”
Steed said that recycling plant waste would save about six percent of the potting soil costs each year and the freight to deliver that much soil to the nursery, minus materials and labor to solarize the plant waste materials.
For more information on the SSARE project, “Large Scale Recycling of Used Potting Media with Solarization (OS13-075),” visit the national SARE project database.
Published by the Southern Region of the Sustainable Agriculture Research and Education (SARE) program. Funded by the USDA National Institute of Food and Agriculture (NIFA), Southern SARE operates under cooperative agreements with the University of Georgia, Fort Valley State University, and the Kerr Center for Sustainable Agriculture to offer competitive grants to advance sustainable agriculture in America's Southern region.