Winter Squash + Nasturtium

Nasturtium is one of the more reliable companion plantings for winter squash, primarily because it deters squash bugs (Anasa tristis), which are the most damaging pest for this crop in most regions. The mechanism appears to be chemical deterrence and physical disruption of pest movement rather than any nutritional benefit to the squash itself.

Spacing matters here. Nasturtium should be underplanted at the base of squash hills or along row edges so it can sprawl between the larger plants as both mature. Direct sow nasturtium at the same time as squash seeds or transplants; nasturtium germinates quickly and establishes without competing aggressively for nutrients. Both crops tolerate similar soil conditions, though nasturtium actually performs better in leaner soil, so avoid heavy fertilization near nasturtium if blooms and pest-deterrent effect are the goal.

This pairing is most useful in regions with consistent squash bug pressure. Where squash bugs are rare or absent, nasturtium still adds pollinator traffic without causing harm, but the benefit is less pronounced.