Cucamelon and Nasturtium
Beneficial Pair — Good Match
Nasturtium's aphid preference is documented in general, even without a cucamelon-specific trial, which keeps this above traditional lore. Cucamelon is enough of a niche crop that we're not aware of any dedicated companion-planting research on it at all, so the rating reflects extending a general mechanism to an unstudied specific plant.
Mechanism: Trap Cropping
Cucamelon is a cucurbit and, like its relatives, is genuinely appealing to aphids at its growth tips - the same mechanism cited for nasturtium's other cucurbit pairings on this site applies here. What's different is cucamelon's growth habit: it's usually trained up a trellis rather than left to sprawl across the ground, which means nasturtium at its base isn't competing for the same low, horizontal space the way it does with a sprawling squash or pumpkin.
Cucamelon is one of the less commonly grown crops on this site, a small, grape-sized fruit related to cucumbers that's usually trained to climb rather than left to sprawl the way its more familiar cucurbit relatives do.
A Trellised Cucurbit Solves the Usual Space Conflict
Most nasturtium-and-cucurbit pairings on this site run into the same problem: both plants grow low and spread wide, competing for the same ground-level space. Cucamelon's climbing habit sidesteps that entirely - trained up a trellis, it frees the soil at its base for nasturtium to occupy without the shading-out conflict that comes up repeatedly with sprawling zucchini, pumpkins, or summer squash. It's a more favorable spatial arrangement for this pairing than most of its cucurbit cousins offer.
Spacing
Because cucamelon climbs rather than sprawls, nasturtium can be planted much closer to its base than to a sprawling squash - cucamelon's 12-18 inch spacing leaves the ground level mostly free once the vine is established on its trellis, unlike the ground-level competition nasturtium runs into with zucchini or pumpkins.
Watch For
Cucamelon fruits are small, roughly grape-sized, and the plant can be easy to overlook among more vigorous garden vines - keep an eye on where the trellis line actually is so nasturtium doesn't end up planted somewhere the cucamelon's climbing growth won't reach or benefit from.
Frequently Asked Questions
Does cucamelon need a trellis, or can it be grown like a regular cucumber vine?
It can sprawl on the ground if left untrellised, similar to a bush cucumber, but it's more commonly grown vertically since the vine is vigorous and the small fruit is easy to spot and pick at eye level on a trellis rather than searching through ground-level foliage.