An Analysis of the Quality of Compost Produced from Vermicomposting Fresh Cut Flower Waste

Higher levels of pesticide applications are used when growing cut flowers when compared to other crops such as tomatoes, lettuce, and rice, much of the floriculture industry production occurs in developing countries where less environmental regulations may be in place compared to those in the United States. Therefore, special consideration should be given to cut flower disposal from floral shops due to the potential excessive leaching of pesticides into land and waterways. Most retail florists in the industry dispose of their floral waste into municipal dumpsters. There are an estimated 13,200 retail flower shop locations in the United States, comprised of single location and multiple location companies. While the United States Department of Agriculture (USDA) has stringent guidelines to prevent the importation of pests and plant diseases, there are no regulations on the disposal of spent floral crops that may contain residues of pesticides or other chemicals. Vermicomposting is a method of composting used for pollution abatement while having the added benefit of acting as an alternative waste management method to traditional landfill dumping. The castings produced are a valuable commodity for agricultural, horticultural, and related industries. The main objective of this research was to analyze the quality of compost produced from vermicomposting fresh cut floral waste. Analysis of results was based on the U.S. Composting Council's Tests Methods for the Examination of Composting and Compost used by the U.S. Composting Council's Seal of Testing Approval (STA) program. When compared to STA standards, pH, soluble salts, organic matter, total nitrogen, carbon, carbon-to-nitrogen, bioassay, and respirometry all were found to be within normal ranges for compost sold in the horticulture industry. Chemical analysis found the level of arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, zinc all to be well below set industry standards. Additionally, the vermicompost was lab tested for 23 herbicides and insecticides. Of those, one herbicide (clopyralid) and two insecticides (clofentezine and lufenuron) were found in the sample in trace amounts, and well below Environmental Protection Agency (EPA) set industry standards for acceptable trace amount in U.S. products. Results indicated floral waste collected from retail flower shops can be incorporated into a vermicomposting system to create a quality compost suitable for use in the horticulture industry.