By Denny Schrock, Colorado State University Cooperative Extension agent, horticulture
Hot weather and cucumbers are a perfect mix. Cucumbers need heat to grow well, and once they're on the table, their high water content makes them a great hot-weather food.
Direct seed cukes outdoors from mid-May to about the first of July. Speed early season growth by planting through black plastic mulch and covering with spun-bonded row covers. Plastic warms the soil and row covers trap heat around the plant.
Row covers also keep cucumber beetles off the plants. The larvae of these pesky bugs feed on roots; adults chew flowers and leaves. But even worse, they carry bacterial wilt disease that can kill plants quickly. Row covers may be left in place until temperatures reach the 90s or until female flowers begin forming.
Most cucumbers must be cross-pollinated to set fruit. Vines produce separate male and female flowers. Male flowers have a slender stalk at their base. Female flowers are swollen at the base. The first flowers produced on a plant are all male. Lack of early season production may simply be a matter of waiting for female flowers to develop.
Some varieties are all female or gynoecious. Expect 20 to 25% higher yield with gynoecious lines. `Raider' is one that topped variety trials at Colorado State University last year. All female varieties require a cross-pollinator. Plant other varieties nearby or be certain to use the pollinator seed included in the packet.
`Sweet Success' slicing cucumber and `County Fair 83' pickling cucumber are parthenocarpic varieties. They develop fruits without pollination. If pollinated, the fruit may be misshapen.
Other Types of Cukes
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010