Bensulide (Prefar®), clomazone (Command®), sulfentrazone (FMC), and halosulfuron (FMC) treatments applied preemergence (PREE) gave very good weed control of prostrate pigweed (Amaranthus blitoides), lambsquarters (Chenopodium album), and common purslane (Potulaca oleracea) at 5 weeks after treatment (WAT). Bentazon (Basagran ® and halosulfuron applied postemergence (POST) alone were marginally effective at less than 85% against the pigweed species at 2 WAT and controlled lambsquarters and common purslane. POST treatments following PREE treatments were highly effective to control most weeds. Watermelon injury was acceptable for Command and halosulfuron treatments. Basagran caused slight injury when applied POST on the watermelons. Carfentrazone was not effective against the weeds present in this test site and was safe on the crop. The greatest number of marketable watermelons were harvested from plots having treatments that provided effective weed control. Command plus Prefar PREE followed by Basagran POST and Prefar PREE followed by halosulfuron POST treated watermelons yielded high numbers of marketable fruit.