Cucumbers are a rather exuberant crop with vines that can sprawl over a lot of space—the healthier the cucumber plant, the more space they seem to take up. But space requirements aside, cucumbers can also play well with more types of vegetables than you think.
Cucumbers (Cucumis sativus) are in the same family as squash and melons and can be eaten fresh or pickled for later use. There are some plants that make good garden neighbors to cucumbers, and several that should be avoided. You may be surprised to learn that melons, cucumbers' cousins, are poor matches to grow nearby.
What Is Companion Planting?
Companion planting is the close planting of different species based on their ability to enhance one another's growth, offer some form of pest protection, or other advantages. Sometimes this is a matter of choosing plants with different growth habits that do not compete with one another, or it can mean choosing companions that have different nutrient needs in order to make efficient use of soil. While scientists haven't published findings on companion planting, many gardeners swear by it. Some companion planting simply involves common sense—making sure that taller plants don't provide too much shade to low-growing plants, for instance.
Strategic companion planting is especially important in small gardens or wherever careful space planning is needed.
Because vining cucumbers need a trellis to keep the fruit off the ground and prevent diseases, corn or sunflowers can act as a natural trellis for cucumber vines. Cucumbers require at least one inch of water per week to thrive and avoid bitter fruit, and they'll be situated well near corn and sunflowers, as they won't compete heavily with cucumbers due to their less thirsty habits. Bush cucumber varieties, however, don't require a trellis and may compete for sunlight and space with corn and sunflowers.
There are many vegetables that make excellent companions for cucumbers. Peas, corn, beans, and lentils are legumes—a type of plant that has a root system that increases nitrogen in the soil. The mechanism by which this happens is that roots have the ability to colonize the Rhizobium bacteria and absorb about 20 percent of the sugar produced by the plant—which is then turned into nitrogen. Any of the nitrogen not absorbed by the legume is released into the nearby soil as the plant decomposes, thereby becoming available to nearby companion plants. This will benefit your cucumber plants, as well as many other garden plants. Other good vegetable companions include radishes, beets, carrots, and onions.
Marigold flowers will help repel beetles, and nasturtiums are distasteful to thrips and other insects that feed on cucumbers. These flowers, along with sunflowers, make for good companions for almost all vegetables and herbs.
Oregano is an herb with a well-established reputation for repelling insect pests and is another good companion for cucumbers, as is dill. Dill attracts beneficial predatory insects to the garden as well, which help rid it of pests.
Poor Companions for Cucumbers
Just as some plants are good companions together, there are also those that should not be allowed to reside side-by-side.
Potatoes compete mightily with cucumbers for nutrients and water, so they should not be planted together. Cucumbers also encourage potato blight, so avoid planting these crops together.
Sage is reported to stunt the growth of cucumbers, so plant it elsewhere. Avoid mints as well, as they are overly aggressive in garden beds and can infringe on both the space for cucumbers, as well as its nutrients. Contain mints in a pretty pot instead.
Pests that enjoy cucumbers also find melons tasty. To protect both crops, plant them away from one another.