Depending on who you ask, a healthy cucumber plant can be expected to produce 10 large cukes or 15 small ones within a harvest period of about three weeks. These optimistic averages are based on large, field-size plantings managed by pros, but gardeners can match or better these numbers by using cultural methods that maximize the productivity of cucumber plants.
More than 30 years ago, American horticulturalist H. Y. Hanna observed higher productivity when growing cucumbers on a trellis. Hanna proposed that when the vines are trained upward, so that the leaves form a mound or hedge of layered foliage, cucumbers benefit from improved overall photosynthetic capacity and make more energy from the sun. Since then, field trials in several locations have shown that when properly managed, trellised cucumbers can produce two to three times more cucumbers than plants allowed to run over the ground.
A partial explanation is that trellised cucumbers are easier to harvest because you can see them more easily, and you are less likely to miss big overripe fruits. In addition, it is easier to prevent and control problems with pests and diseases when growing cucumbers vertically. This morning in my garden, for example, a gentle tap to several open flowers sent a half dozen cucumber beetles to a drowning death in a bowl of soapy water – a maneuver that would have been impossible with vines running on the ground.
The top yield figures have been obtained by training cucumbers up a sturdy wire fence, 6 feet (2 m) high, but there are endless ways to support your crop. Keep in mind that the vines cling with curling tendrils, so they often need help finding their way. Also avoid using fencing or netting that cannot be reached through with a hand holding a cucumber!
Once a cucumber vine is trained to waist height, the plants’ secondary stems emerge and the formerly restrained vine explodes into a wall of foliage, flowers and fruits. At this point additional support from stakes or string is usually needed around the outside of the planting if the vines and fruits are to continue to set fruit above the ground.
How Cucumbers Set Fruit
Open-pollinated heirloom varieties like ‘Boothby’s Blonde’, shown above, are called monoecious types because they produce both male and female flowers on the same plant. Male flowers usually appear first, presumably to attract the attention of pollinators, followed by a profusion of male and female flowers all at once.
The majority of disease-resistant hybrid cucumber varieties produce mostly female flowers, which means they are gynoecious cucumbers. In strongly gynoecious varieties, a few seeds of a monoecious variety are included in the packet to boost fertilization.
To make things more confusing, there are parthenocarpic cucumber varieties, which set fruit without pollination, and in fact produce the best quality, seedless fruits when grown in greenhouses or high tunnels from which pollinating insects are excluded. Note that many “greenhouse” varieties are often poor performers in the open garden compared to sturdy hybrids and established heirlooms from around the world.
If your eyes are glazing over from all the tech talk, don’t worry. Regardless of how their flower-producing genes have been lined up by vegetable breeders, cucumber plants regulate how many fruits they will produce. If the first two or three flowers that appear on small plants are nicely fertilized, plant growth will slow as the plant assumes that its job is done – seeds have been set for the next generation. But if the first female flowers shrivel naturally, or are pinched off (baby cuke and all), the message surges through the plant that more flowers and fruits are needed. New growth ramps up. It is therefore ideal to pinch off the first few fruits that form in the interest of productivity. After that, the plants know what to do.
Keeping Cucumbers Healthy
Cucumbers that are planted in fertile soil are often ready for a supplemental feeding when the plants suddenly grow large and begin to run. A balanced organic fertilizer that contains a buffet of nutrients is ideal. Whether you scratch a granular fertilizer into the soil around plants or drench them well with a water-soluble plant food, do not skip this important step. Adequately fed cucumber plants have far fewer problems with disease, which in turn helps them produce beautiful fruits for a longer time – hopefully more than a dozen.