If your lettuce is bitter and your spinach is going to seed, don’t be disheartened. There are some vegetables that enjoy the heat of summer. The cucurbits, or vine crops, include such favorites as cucumbers, squash, melons and pumpkins. Although each of these taste quite different, their culture is very similar.
Cucurbits are warm-season crops that are notorious for taking over large amounts of garden space. Fortunately, plant breeders have developed the so-called “bush-type” plants that produce shorter vines. So even an urban gardener who has limited space can grow a few of these popular plants.
Cucurbits can be given a head start by sowing seeds about three weeks before the average last frost and then transplanting to the garden. But if the soil is warm, above 60 F, direct seeding is almost as fast. Planting in hills is a common practice, accomplished by mounding soil 8-10 inches high and planting 4-6 seeds in a circle in the hill. Hills should be spaced 4-8 feet apart, depending on the type of cucurbit. Once the seeds have germinated, thin the stand to 2-3 of the healthiest plants.
Cucurbits have separate male and female flowers on the same plant, and bees are required to carry the pollen from the male blossoms to the females. The female flowers are easy to identify; they appear to have a small fruit below the petals. Quite often, the first flowers of the season will be all males, which fall off the plant without producing any fruit. Just be patient. The next flush of flowers should include both male and female blooms, and the females will produce the fruit, assuming that pollination is successful.
Frequent harvesting is key to a productive planting of cucumbers and summer squash, which are harvested while quite immature. Allowing even just a few fruits to mature on the vines can signal the plant to stop producing. If a few fruits have escaped your attention and are too old for good eating, pick them anyway and add them to the compost pile.
Melons need to stay on the vine long enough to sweeten up, and the exact harvest window depends on the type of melon. Muskmelons (incorrectly but frequently called “cantaloupe”) usually “slip” from the vine, as well as change color on the rind under the outer netting.
Watermelons are much more mysterious — many gardeners look at the ground spot (where the melon was resting on the soil) and harvest when the spot changes from whitish to yellowish. The tendril closest to the vine is also said to turn brown when the melon is ripe, but this is not always reliable!
Pumpkins and winter-type squash must be left on the plant until the skin is hard and the colors deepen. Plants can be covered during light frost to help the plants last a little longer, but harvest all of the fruit before a hard frost or freeze. Remove the fruit from the vine with a portion of the stem attached, and store on shelves in single layers for good air circulation.