By Wade Hilber – Burnet County Ag Extension Agent
Q. Why do my cantaloupes bloom and bloom but seldom set any fruit?
A. Cantaloupes, like other vining crops such as cucumbers, pumpkins, squash and watermelons, require pollination for fruit set. This means pollen must be transferred from the male blooms to the female blooms. Although cantaloupes are different than other vining crops because they have flowers which contain male and female parts as well as those which contain only male parts, pollination by bees is still necessary. High temperatures or high fertility can cause the cantaloupe to produce only male blooms which results in poor fruit set. Nematodes can also cause small plants, profusion of blooms and no fruit. Root knot is a species of nematode which causes galls or swellings on plant roots. It restricts the uptake of nutrients from the root system to the foliage, resulting in a yellow and stunted plant. Root knot lives in the soil and can survive on a number of weed and vegetable crops. It is best controlled by planting a solid stand (close enough for root systems to overlap) of marigolds three months before the last killing frost of fall and/or planting cereal rye (Elbon) for a winter cover crop. Cereal rye should be shredded and tilled into the soil 30 days before planting a spring crop.
Q. Are bees necessary for pollination and fruit set in home- grown cantaloupes?
A. Although cantaloupes produce some perfect flowers (those that contain male and female parts) which can set fruit without pollen from a male flower, an adequate supply of bees during bloom will insure an abundant cantaloupe harvest. Most problems with fruit set in cantaloupes are caused by a lack of pollinating insects during the blooming period.
Q. Can cantaloupes cross-pollinate with other crops such as cucumbers, watermelons, squash or pumpkins?
A. Crossing between members of the curcurbit family is rare. If crossing occurs, it will not show up in this year’s fruit but will be evident if seed is saved from these fruits to plant in next year’s garden. Many people rate off-flavored or strange- colored fruit with cross-pollination, but it is usually caused by environmental conditions or disease. The curcurbit family (cucumber) will not cross pollinate with the citron family (melons).
Q. What is the best way to determine when a cantaloupe is ready for harvest?
A. The cantaloupe is ready to harvest when the stem easily separates from the fruit. To avoid over-ripening, harvest cantaloupes before they naturally separate from the vine. The best way to check maturity of cantaloupes is to place your thumb beside the stem and gently apply pressure to the side. If the stem separates easily, the cantaloupe is ripe.
Q. Some years my cantaloupe are sweet and tasty and other years they have no flavor at all. What is wrong?
A. Cantaloupe flavor depends upon environmental conditions. High rainfall or excessive irrigation as the cantaloupes near maturity will adversely affect fruit flavor. Also, diseases which reduce the vigor of the plant and the leaves’ ability to produce sugar will affect fruit flavor. Maintaining the plants in a healthy growing condition and avoiding excessive watering near maturity will improve cantaloupe flavor. Lack of flavor is not caused by cantaloupes crossing with other vine crops, such as cucumbers. Variety of cantaloupe grown affects flavor.
Q. Can you save seed from this year’s crop of cantaloupes for planting in next year’s garden?
A. Yes, but this is not recommended. Do not save seed from any vine crops because some cross-pollinating can become evident when the seed are planted in next year’s garden. If you grow only one variety of cantaloupes and there are no cantaloupes in neighborhood gardens, seed can be saved for next year without producing off-type fruit. If hybrid varieties are used, you should not save seeds for next year’s planting.
Q. What is the difference between a honeydew and cantaloupe?
A. Honeydew melons are closely related to cantaloupes but ripen later. Most honeydew melons have white or green flesh and mature within 100 to 120 days after planting. Honeydew melons do not slip from the vine as cantaloupes do and are mature when they become creamy to golden yellow in color and the blossom-end softens slightly.
Q. The foliage on my cantaloupe is developing yellow spots with a downy growth underneath.
A. This is downy mildew and can be controlled with resistant varieties (Top Score, TAM Uvalde, Perlita and PMR 45) and fungicide applications using chlorothalonil.
Q. The foliage of my cantaloupes is covered by brown, dead spots which fall out giving the foliage a very tattered appearance.
A. This disease can be controlled with fungicide applications at 10- to 14-day intervals. Use chlorothalonil.
Q. The stems near the crown of my cantaloupes are splitting, and an amber-colored ooze is forming around these cuts. Soon after this happens, the plants wilt and die.
A. This is gummy stem blight. It is a soil-borne fungal disease that infects and kills young plants. It can be controlled with benomyl sprays applied at the crown of the plants when they are just beginning to form runners. Rotation within the garden will also help prevent this problem.
Q. After the recent rains, my cantaloupes began to rot. Around the base of the decay there was a white fungal mat.
A. This is southern blight. The control for this is mulching between the fruit and the soil. Heavy soils will be more prone to this problem than light, sandy soils. Chemicals do not prevent this. Waterings should be light and quick so the soil does not stay wet for long.
Q. The roots of my cantaloupe plants are covered with knots and small swellings.
A. These are root knot nematodes. Root knot is a species of nematode which causes galls or swellings on plant roots. It restricts the uptake of nutrient