Cantaloupes are melons in the cucurbit family, the family of which cucumbers, pumpkins, gourds and squash are also members. They require heat and no environmental stress to produce sweet fruit. Lack of water, overwatering, pests and disease all cause poor fruit quality in cantaloupes.
The plant has both male flowers and complete flowers containing male and female parts on a single plant. The complete flowers are identifiable by the immature fruit appearing like a knot below the flower. If pollination does not occur, the plant flowers without setting fruit.
Disease such as root knot, caused by a nematode infesting roots, cause excessive flowering without fruit set. Nematodes live in the soil and are killed or prevented by planting a high-nitrogen cover crop like cereal rye before using the soil for melons. Shred and till the crop under before planting curcubits.
Planting pollinator-friendly flowers near the melon patch encourages pollination. Many weeds such as dandelions attract bees and butterflies, as do lilac, butterfly bush, and various wildflowers. Keeping a bee habitat intact helps not using mulch in your garden and leaving wood piles or brush piles where bees nest.
Pollinate your melons by hand to ensure fruit set. Carefully pluck a male flower and brush it into a female flower, being sure the pollen gets down into the heart of the flower. A single male flower can pollinate four female flowers.