Knowing how to plant watermelons and cantaloupes is critical to producing fully ripened sweet and luscious melons that when chilled are crisp and delicious as a breakfast dish or served as a fat-free dessert. Plant the melons early enough in the spring to allow them time to ripen over the summer and be harvested before the first frost. Start melon seeds indoors under controlled conditions to produce a high rate of germination and less seed loss due to birds, rodents and weather. This process speeds up the ripening time by as much as three weeks.
Starting Seeds Indoors
Start seeds indoors two months before planting time by using seeds treated to ward off typical diseases that attack seedlings, such as an anti-fungal damping-off disease. Seeds are available at garden centers.
Use peat pots, trays or plastic flats with a drain hole in the bottom. Fill the container level with the top with a potting soil mix that is light, loose, holds water well and is free of diseases, insects and weeds.
Place the planter container in a pan of water 2 inches deep and leave overnight so the soil can soak up water through the drain holes.
Plant five seeds into each container by gently pressing them into the soil to a depth of 1 inch and cover them loosely with soil.
Cover the container with plastic film to hold in the moisture and remove it when the seeds germinate.
Place the containers in a warm location, out of direct sunlight, with a temperature range of 65 to 75 degrees F.
Inspect the plants, after germination, for damping-off disease and apply a fungicide.
Place the germinated seedlings in direct sunlight in a bright south-facing window with eight hours of sunlight daily. Fluorescent lighting can be used when sunlight is not available. Place the fluorescent lighting 4 inches from the seedlings for 14 to 16 hours per day until the seedlings become larger, when the fluorescent lighting can be placed further away.
Water the seedlings every other day until the soil is moist and apply a water-soluble fertilizer at half the recommended rate shown on the package directions, once every two weeks.
Thin the weaker plants from the containers so that the number of plants is appropriate to the size of the container.
Transplant the melons to larger peat pots, with good drainage, to allow the plants to grow to a larger size. Peat pots can be planted directly into the garden. Inspect the soil daily by inserting your finger 1 inch into the soil; if the soil is dry, water until the soil is moist throughout.
Harden the plants by placing them outside in a shaded area two weeks before planting in the garden. Each day expose the plant to sunlight for a longer period of time until it is time to place them in the garden. Reduce watering and do not expose the plant to freezing temperatures or strong winds.
Move the plants to the garden with full sun and rich fertile soil with a pH in the range of 6.0 to 6.5 when the soil temperature reaches 55 degrees F. Use a hoe to create hills or mounds of soil down each row that are at least 2 inches high and 12 inches wide. The hills should be 6 feet apart for watermelons and 2 feet apart for cantaloupes to allow adequate room for the plants to grow.
Dig a hole large enough to place the transplant, still in the peat pot, directly into the hole and loosely pack soil around the pot. Plant the watermelon seedlings 6 feet apart and the cantaloupe seedlings 2 feet apart.
Water the plants twice per week by applying water directly to the root system to a depth of 6 inches until the fruit develops. Once the fruit has developed, cut the watering back to once per week. Stop watering one week before harvesting the melons.