Cucumbers don't cross with watermelons, cantaloupes, pumpkins or squash. And cantaloupes don't cross with cucumbers, watermelons, pumpkins or squash. Summer squash varieties will cross with each other and with pumpkins, but not with winter squash. Note that even though a cross may occur, the appearance of the fruit won't change until you plant the seed from the cross, and it produces fruit the following season. The only cross that can show up the first year is corn.
Sweet corn can easily cross with field corn, which produces starchy-tasting corn the same season.
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