If you leave em on the vine, they'll keep growin until they're as big as watermelons, but they ain't good to eat. Don't plant them to close to your squash, cause they'll cross up and you'll have a great big green thing that nobody knows what to do with. We used to cut the type you got when they were only about 4 or 5 inches long, whatever will fit into a fruit jar when we canned them.