Melons prefer soils with a pH between 6.0 and 6.8 which indicates adequate calcium availability which is an important guard against blossom-end rot. Try one of the 10 Easy Soil Tests to determine the pH level in your soil. Work 2- to 3-inches of finished compost into your melon beds before planting. Adding compost provides nutrients for your melons, helps to distribute moisture evenly, and furnishes oxygen for root growth.
Soil temperature must reach at least 60°F before you plant, which is about a week after the last frost.
If you direct-seed, sow seeds in clusters of five or six, planting each cluster in a hill of soil 1-foot high by 2- to 3-feet wide to increase drainage. If you're using seedlings, plant two or three per hill. For muskmelon and honeydew plants, space hills 1½ to 2 feet apart, leaving 4 to 6 feet between rows. For watermelons, add another foot or two to these guidelines.
Melons need about an inch of water each week. Water your plants carefully by hand or use drip irrigation, because wet foliage promotes the spread of diseases such as angular leaf spot and downy mildew.
Mix a solution of 1 tablespoon of fish emulsion in 1 gallon of water as an organic fertilizer, and apply it weekly when the plants are young. An application of a kelp-based foliar spray when the plants are in full flower will complete fertilization.
Keep an eye out for squash bugs, cucumber beetles—which also carry bacterial wilt—squash vine borers, and aphids, carriers of mosaic viruses. Look into adding a few of the 10 Insects You Should Actually Want Around Your Plants to your plot to help control detrimental pests before they become a problem.
Preventing Powdery Mildew should be your focus when growing melons this season, and although it can be one of your biggest issues, make sure to keep an eye out for other problems like mosaic viruses and angular leaf spot.
Pick cantalope when the stem separates easily from the melon. For netted melon varieties, the skin between the netting will turn from green to yellow at ripeness. Honeydews will soften slightly on the flower end of the fruit when ripe along with a slight change in fruit color. Check the belly of watermelons for the best indicator of ripeness; the belly turns from greenish white to buttery yellow or cream at maturity. This change is most noticeable on watermelons with dark green skin.