If I want to save seed from my pumpkin, how far away should I plant them from the watermelon or cucumber, so they don't interpollinate? Thanks!
1/2 mile apart from if you are saving seeds to sell as pure seed.
Pumpkin will cross pollinate with Acorn Squash, Delicata Squash, Zucchini and other summer squash. 1/4 mile apart if you don't mind an occasional seed that is crossed.
Row covers would be also another recommendation.