BOSSIER CITY, LAPerlite, a processed volcanic mineral, is widely used as a component of soilless growing mixes. Lightweight, sterile, and easy to use, perlite is popular with greenhouse growers. But because salt and pathogen buildup can occur when perlite is reused, it must be replaced every year or two to minimize the risk of crop failure. The cost of disposing of old material and replacing it with new perlite can be significant and often prohibitive for smaller greenhouse operations. Hanna Y. Hanna, a researcher at Louisiana State University Agricultural Center's Red River Research Station, has developed a new method for recycling perlite that can save tomato growers a significant amount of money without reducing crop yield.
Hanna, who has done extensive previous research on perlite, says that using the same perlite to grow successive crops like tomatoes can be risky; it tends to compact and is subject to salt build-up and pest contamination. "Steam sterilization of used perlite before planting a new crop is recommended to safeguard against pathogen contamination, but this treatment requires the use of expensive steam generators and is not efficient in desalinating the medium", Hanna said.
In a recent issue of HortTechnology, Hanna reported on a new method developed to accelerate the recycling of perlite. The experiments were conducted in a greenhouse over three growing seasons to evaluate three different methods for perlite recycling and their effects on cost, desalination efficiency, and tomato yield.
Three recycling methods"no stir/sift-then-disinfect", "stir-then-disinfect", and "sift-then-disinfect"were put to the test for Hanna's experiments. Each recycling method consisted of two components: the reconditioning action and the hot water treatment. During the experiments, perlite recycled with the no stir/sift-then-disinfect method was not reconditioned before the hot water treatment. Instead, it was agitated with a nozzle m
|Contact: Michael W. Neff|
American Society for Horticultural Science