Cucumbers are tender annual vines in temperate zones, first domesticated during prehistory in tropical Asia. They can’t take the slightest bit of frost; in fact, even a moderately long spell of cool, wet weather is enough to steal their vigor and make them lapse into a downward spiral. But given rich soil, warm weather, and a place to run, they’ll outgrow just about any other plant.
We put cucumbers in the second part of our rotation. Before planting we add some extra compost to their bed to help get the early growth going. Once the last spring frost is gone and the weather settled, the seed can be sown, three seeds to the foot, 1/2 to 3/4 inch deep in a single row down the center of the bed, or in rows three to six feet apart.
North of USDA Zone 8 it helps to start the plants indoors in large soil blocks or cell trays a couple of weeks before setting out—but no sooner, because rootbound seedlings will never amount to much. The plants are then set out one foot apart in a row down the center of the bed. At transplant time I make a small depression in the soil with my hand, fill it with an organic mixture—made with a tablespoon each of fish fertilizer and liquid seaweed to a gallon of water—plop the plant’s root ball right down in it, then pull a bit of dry soil back over the spot. Since the roots are so tender I let the liquid settle them instead of packing the soil with my hands.
Whether we direct-sow or set transplants, we cover the bed immediately after planting with a floating row cover to keep off cucumber beetles. If they find the seedlings at this stage—and they always seem to hatch right at cucumber planting time—they can kill the plants within a matter of days. Keep the cover on until the plants flower or the beetle’s first reproductive cycle is over and you’ll lessen the damage quite a bit.
Unless you’re going to grow them in with the corn, I’d recommend trellising cucumbers. Trellising increases yields, decreases disease, and helps with both pest control and harvest: to me that’s a convincing list of advantages. When the plants begin to run (or flower, whichever happens first), we take off the row covers. By then the plants are growing fast enough so that the remaining cucumber beetles can’t really hurt them physically, though the beetles still carry disease.
Then we set up the same kind of trellis we use for pole beans and tall peas, rigged with a vertical line for each plant and horizontal lines every foot or so. Gently lifting the vines, we wrap each around one of the vertical lines and then leave them to their own devices. Within a week they’re headed for the top.
Probably the worst thing about cucumber beetles is that they spread bacterial wilt and cucumber mosaic. Bacterial wilt dries up the leaves and causes them to wilt. You can check suspicious plants by cutting across a stem; if it oozes a sticky white juice, pull it up, destroy it, and replant. Cucumber mosaic causes the leaves to mottle, curl, yellow, and eventually fall off. If there are fruits on the vine they’ll be small, light-colored, and warty. Many new cultivars are resistant to these diseases. Still, try to control the beetle if it causes you problems; mosaic is also spread by aphids.
Cucumber beetles and aphids can also be controlled with a mixture of rotenone and pyrethrum, but I’ve found it isn’t worth the trouble. Replanting frequently in different parts of the garden is just as effective.
Cucumbers are more than 90 percent water, and so they shouldn’t be allowed to suffer for lack of it. If you’ve ever seen a cucumber shaped like a barbell instead of smooth and cylindrical, you’ve seen a visual record of the season’s water supply: the fruits grow fat during periods of ample water and skinny during drought.
Since trellised crops need more water than sprawling plants, and are more difficult to water by overhead irrigation, cucumbers are an excellent candidate for drip irrigation, and this will make it relatively easy to maintain a consistent moisture supply.
The first few flowers that appear on your cucumber plants will be male flowers, and will not produce fruit. They are generally borne in clusters, while the female flowers are single and borne at the end of a small fruit (which is the ovary). The single most important thing you need to know about harvesting cucumbers is that they have to be kept picked; if any fruits are allowed to ripen, the plant will stop producing fruit. A mature cucumber is yellow, and if you see one turning that color, pick it and toss it on the compost pile or into the chicken yard.
Cucumbers are ready for harvest at any point after the female flower falls off the end of the fruit. You don’t need to grow a special variety for pickling, either. Just harvest the tiny fruits and pickle them whole. At that point they are ideal for pickles because they haven’t yet taken up a lot of water, and when you put them in the pickling syrup they can absorb that instead—with no need for salting first. Once the vines begin to bear, the fruits seem to grow almost overnight, and should be checked frequently. For fresh use, harvest just as the dimple that contains the spines fills out. At that point the cuke will be swollen and juicy, but the seeds and skin won’t have begun to harden.