Cucurbit Crops - Horticulture Pick off and discard large or damaged fruit to keep the plant producing new flowers and fruit. Watermelons: Harvesting watermelons at the correct stage of maturity is critical and difficult. While each cultivar is different, maturity can be determined in several ways, including ground spots changing from white to yellow, browning of tendrils nearest the fruit, and a hollow or dull sound when " thumped " . Watermelons should be cut from the plant to avoid vine damage and prevent stem-end rot. Leave 1 to 2 inches of stem attached. Midwest Veg Guide 2022 123