What to Plant With Cucumbers and Squash (and What the Research Says)
Quick answer
A border of Hubbard-type winter squash draws striped cucumber beetles away from cucumbers, squash and pumpkins, but in UMass farm trials it worked because the border was treated. An unmanaged border is untested, but in one Utah State trial, Hubbard plants with the squash bugs picked off by hand cut squash bugs on nearby pumpkins. The squash family tolerates black walnut, and Three Sisters (corn, beans, squash) is a described intercrop.
Updated
The best-tested companion for cucumbers, squash and pumpkins is a border of Hubbard-type winter squash as a trap crop for striped cucumber beetles. In farm trials it worked because the border itself was treated with insecticide. An unmanaged border is untested, but a hand-picked Hubbard border cut squash bugs on nearby pumpkins in one Utah State trial. Unlike tomatoes, the squash family tolerates black walnut.
Cucumber and squash companions: the evidence
| Claim | What the research says | Evidence |
|---|---|---|
| Hubbard squash trap border | Works at farm scale with a treated border. UMass Extension: a more attractive crop is planted “around the outer edge of the main cash crop”, and “Pesticides applied to the border prevent further invasion of the main crop.” Beetles “concentrated in high numbers on Hubbard squash borders.” When the border treatment was delayed, “the border was destroyed by feeding damage” and “beetles flowed into the main crop” (UMass Extension, Using Perimeter Trap Crops to Manage Striped Cucumber Beetle). A border left unmanaged is untested; see the hand-picked Utah State trial below. The border only worked because it was sprayed. If you treat a border, the product label must list the crop you are spraying, and follow the label. | Strong(farm trials, treated border) |
| Perimeter trap crop for beetles and squash vine borer | UConn: “Preliminary research in Connecticut has shown that PTC can reduce pesticide use, while lowering cucumber beetle and SVB infestations on summer squash by up to 95% and 88%, respectively.” As in the UMass trials, the border was treated; for vine borer it “must be sprayed during the adult flight” (UConn IPM, Perimeter Trap Cropping for Summer Squash). In Massachusetts butternut squash trials, UMass reports: “The main butternut crop of the PTC system fared as well as the main crop of the conventional system – even though the PTC crop was never sprayed.” (UMass Extension; peer-reviewed: Cavanagh et al. 2009, Journal of Economic Entomology 102(3):1101-1107) | Strong(farm trials, treated border) |
| Hubbard trap plants for squash bugs on pumpkins, picked by hand | Utah State put Hubbard squash at the ends of each pumpkin row, “planted two weeks prior to the pumpkins”, and removed squash bugs by hand from the Hubbard plants only. “Results of the squash bug counts showed that there were significantly more adults, nymphs, and eggs on the pumpkins in the plots without the trap crop than on the pumpkins with the trap crop.” USU: “Our trial was on a small scale and we could remove squash bugs by hand.” (Utah State University Extension IPM, Blue Hubbard Squash as a Trap Crop to Suppress Squash Bugs). | Moderate(one season, small plots) |
| Three Sisters (corn, beans, squash) | Described as a working intercrop. WSU: beans fix nitrogen, corn gives beans support, and squash acts as a living mulch that inhibits weed seed germination; the three “don’t outcompete each other” (WSU Extension, The Myth of Companion Plantings). We have not reviewed yield trials. | Moderate |
| Near black walnut | Tolerant. Penn State lists plants “less sensitive or not affected by juglone, including the squash family, beans, onions” (Penn State Extension, Allelopathy in the Home Garden). | Strong |
| Nasturtium or radish repel cucumber beetles | No qualifying test found. That is a gap in the research we reviewed, not proof it fails. | None |
Evidence labels: Strong = several field trials or a clear extension recommendation built on trial data. Moderate = one or two trials, or extension guidance with limits. Weak = suggestive only. None = no qualifying test found.
Myths
- “Any squash row around the garden traps the beetles.” The UMass trials treated the border. When treatment was late, beetles destroyed the border and moved into the main crop.
- “Companion charts tell you what loves what.” WSU: “Traditional ‘companion plant’ charts have entertainment, not scientific, value.”
See the companion planting hub and what to plant with tomatoes.
Sources
- UMass Extension: Using Perimeter Trap Crops to Manage Striped Cucumber Beetle
- UConn Home & Garden Education Center: UConn IPM, Perimeter Trap Cropping for Summer Squash
- American Geophysical Union (peer-reviewed journals): Cavanagh et al. 2009, Journal of Economic Entomology 102(3):1101-1107
- Utah State University Extension: IPM, Blue Hubbard Squash as a Trap Crop to Suppress Squash Bugs
- Washington State University Extension: WSU Extension, The Myth of Companion Plantings
- Penn State Extension: Allelopathy in the Home Garden
Organic options Growing without synthetic sprays? See our organic gardening guides: pest control and fertilizer.