AMES, Iowa – Home gardeners have watched melon vines fill considerable garden space while anticipating harvest time. Most watermelon varieties produce mature fruit 75 to 95 days after seeding and 42 to 45 days after pollination. Cantaloupe requires 35 to 45 days to mature from flowering, depending on the temperature. Horticulturists with Iowa State University Extension and Outreach tell how to determine when melons are ready to harvest. To have additional questions answered, contact ISU Hortline at firstname.lastname@example.org or 515-294-3108.
The fruit of the muskmelon or cantaloupe is mature when the stem slips easily from the melon with slight pressure. The melon is not ripe if the stem has to be forcibly separated from the fruit. Other indicators of maturity are based on touch, appearance and aroma. When ripe, the flower end (the end opposite the stem) of the melon should be slightly soft. As the fruit matures, the skin between the netting turns from green to yellow. Finally, a ripe melon produces a strong “muskmelon” aroma.
Unlike muskmelons, the fruit of honeydews do not slip off the vine when mature. The best indicator of ripeness is a slight softening of the blossom end of the fruit. There may also be a subtle change in the color of the honeydew. Honeydews can be stored for two or three weeks at a temperature of 45 to 50 degrees Fahrenheit.
Harvest watermelons when the underside or belly of the fruit turns from a greenish white to buttery yellow or cream. This color change is especially pronounced on the dark green skinned varieties. In addition, the fruit tends to lose its slick appearance on top and becomes dull when ripe.
For most individuals, thumping or tapping the melon is generally not a good indicator of ripeness. Rapping an immature melon with your knuckles produces a metallic ring. A ripe melon gives off a hollow or dull ring. While experienced home gardeners may be able to determine the maturity of watermelons using the thump test, most individuals will have difficulty differentiating between the sounds.
When harvesting watermelons, leave 2 inches of the stem on the fruit. Watermelons can be stored at room temperature for about one week and for two to three weeks at 50 to 60 degrees Fahrenheit.
Many of the Iowa State University Research and Demonstration farms maintain vegetable and flower gardens to provide gardening ideas and display new varieties available in Iowa. The Iowa State Department of Horticulture conducts flower and garden research at the farms to compare new varieties and gardening techniques across the state. Four farms are hosting August garden fields to share research results and a taste of the garden harvest.