from the publishers of: Verywell, Real Simple, EatingWell, Shape, Parents, Health and Allrecipes
From gherkins to slicers, cucumbers are among the most widely planted garden crops. Cucumbers are relatively easy to grow but can be plagued by a variety of insect and disease pests. We can encourage natural pest management in our gardens by thoughtfully pairing cucumbers with beneficial companion plants. Companion planting is the centuries-old practice of combining plants in the garden in a way that benefits one or both plants. This can be in the form of increased pollination, pest management, or enhanced soil health. The cucumber companions featured here provide a wide variety of services to help you get the most from your plants.
Companion planting is an age-old practice, and many strategies have been handed down from generation to generation. However, it is only recently that science-based studies have investigated the effectiveness of these strategies. Some have proven successful, while others don’t stand up to rigorous testing. The companion plants described below represent those that have stood up to scientific testing. Other traditional bean companions, such as petunias or garlic, may yet be proven effective in future studies.
Cucumber flowers are pollinated by insects, so attracting pollinators to the garden is important. The plants are monoecious, meaning they produce separate male and female flowers on the same plant. Pollinators, including honeybees, bumblebees, and squash bees, fertilize flowers by transporting pollen from male blooms to female blooms. Other important cucumber pollinators include native bee species, syrphid flies (a.k.a. hover or flower flies), and soldier beetles (which are also good predators).
Many of the same plants that attract pollinators to the garden also provide resources that support insect predators and parasitoids of cucumber pests. Parasitoids are non-stinging wasps, flies, and other insects that develop on or in a host, eventually killing it. Parasitoids important to cucumbers include a tachinid fly and a braconid wasp that parasitize striped cucumber beetles. Managing cucumber beetles is important because they transmit plant diseases as well as cause feeding damage. Other common pests of cucumbers include aphids, spider mites, whiteflies, pickleworms, and melonworms.
Borage is a gorgeous plant, with showy blue blooms and crinkled, gray-green leaves. The edible flowers have a cucumber-like flavor, but more importantly, they are highly attractive to honeybees and medium to large-bodied native bees that pollinate cucumber blossoms. They also attract predatory insects and are known to add trace minerals to the soil.
Sweet alyssum is a delightful, low-growing flowering plant that attracts pollinators and natural enemies to the garden. The flowers produce tiny nectaries sized just right to draw in syrphid flies, ladybeetles, and parasitoid wasps, all of which feed on aphids. Syrphid flies are also known to pollinate cucumber blossoms, providing an extra benefit. Plant as a groundcover beneath the cucumber trellis, where plants will benefit from partial shade.
The airy golden flowerheads of dill plants are packed with thousands of tiny flowers that support a diversity of predatory insects, including syrphids, parasitoid wasps, lacewings, and ladybeetles. These predators and parasitoids prey upon a variety of small-bodied garden pests such as aphids,
whiteflies, insect eggs, and young caterpillars. The flowers also attract tachinid flies, an important parasitoid of cucumber beetles, which can be quite devastating to cucumber plants.
Cilantro prefers cooler weather and tends to bolt or set flowers when temperatures rise. This is perfect for companion planting, as it is those umbrella-shaped flowerheads that we want. They attract ladybeetles, lacewings, and syrphid flies that feed on aphids and other small, soft-bodied garden pests. In addition to predators, cilantro flowers attract tachinid flies and parasitoid wasps, which attack cucumber beetles and caterpillar pests of cucumbers.
Botanical Name: Cosmos bipinnatus
The frilly, threadlike foliage and vibrant pink blooms of cosmos are a welcome addition to any garden. Cosmos are members of the aster family (Asteraceae), whose members produce disk-like flowers packed with tiny blooms and surrounded by showy ray petals. These flowers support insects with small mouthparts, including parasitoid wasps, small native bees, lacewings, and syrphid flies – all excellent natural enemies of cucumber pests and a few that also provide pollination.
Companion plants provide pest management through a variety of mechanisms. Aromatic chemical compounds produced in some plants can act as a feeding deterrent to certain pests or cause confusion that prevents pests from finding the main crop. Other plants are highly attractive to target pests and can be used to “trap” them, thereby protecting the main crop. Trap crops are most effective against pests that are commonly destructive and difficult to control through other means.
Tansy produces rambling, ferny foliage and golden yellow button-like blooms. As members of the aster family, tansy blooms consist of hundreds of tiny flowers packed tightly together that support parasitoid wasps, small native bees, honeybees, lacewings, and syrphid flies. Tansy has long been touted to repel cucumber beetles when interplanted with cucumber plants, and recent research supports this claim. Tansy is invasive in many areas and plants should be deadheaded to prevent seed production.
Nasturtiums provide an abundance of pest management services in the vegetable garden. They are highly attractive to aphids and can be planted along the edge of vegetable rows to serve as a trap crop. As aphids congregate on nasturtium, they attract a variety of natural enemies that feed on aphids – acting as a sort of nursery for predators and parasitoids that will move throughout the garden. Nasturtiums have long been planted among squash and cucumbers to manage pests. Recent research shows companion planting with nasturtium to be an effective technique in reducing damage from squash bugs and cucumber beetles.
Bean plants and their relatives fix atmospheric nitrogen from the air, transforming it into forms usable by plants. Soils enriched by bean plants provide an ideal growing environment for cucumbers and other heavy feeders. To take advantage of this service, plant a fall crop of cucumbers in the same bed where beans grew over the summer.
Botanical Name: Raphanus sativus
Radishes are known to provide several services in the garden, from trapping flea beetles to breaking up heavy and compacted soils. Studies investigating watermelon production, a close cucumber relative, found interplanting rows of watermelon with rows of radishes and buckwheat (a plant used to attract beneficial insects) resulted in fewer cucumber beetles on melon plants. Results suggested this impact was due to the plants creating a physical barrier that disrupted the movement of cucumber beetles, rather than any effects of repelling them or attracting beneficial insects. Applying this approach of interplanting cucumbers with radish and/or flowering plants could result in a similar reduction in cucumber beetles. Any efforts to manage cucumber beetles will have the added benefit of reducing viral diseases transmitted by these insects.