Metam potassium (metam-K) is a soil fumigant used commonly in Florida at the end of the tomato and pepper production season. The fumigant essentially cleans a field by killing the established weeds and crops after harvest. The goal of this project was to determine the optimal rate of metam-K for the effective termination of tomato, pepper, and established weeds such as purple nutsedge, goosegrass, and dogfennel. Tomato, pepper, and purple nutsedge at bed center were effectively terminated with the metam-K rate of 65 kg ha^–1. Optimal rates required for the termination of goosegrass and dogfennel were 91 and 156 kg ha^–1, respectively. In contrast, metam-K at 500 to 680 kg ha^–1 was required to terminate purple nutsedge on bed edges. The reduced efficacy of metam-K at bed edge might be related to the limited movement of metam-K in soil.

Nomenclature: Metam potassium; dogfennel; Eupatorium capillifolium (Lam.) Small; goosegrass; Eleusine indica (L.) Gaertn; pepper; Capsicum annuum L.; purple nutsedge; Cyperus rotundus L.; tomato; Solanum lycopersicum L.