This is how to prune a spaghetti squash plant . Now, squash grows from a vine. So, it's much like a watermelon or any other gourd it will grow from a vine. A lot of people that say don't ever prune your squash at all because they'll produce all of this fruit and you can enjoy it and if you prune it at all, you'll cut back on your fruit production. However, it's very good to prune at least one third of the plant back at least once a month because then that will encourage more growth from the existing plants and your squash will be much larger because they're not producing as many squash. The people who are saying not to trim are actually concentrating on the few squash that are on the plant. So, if you have a large plant that's pretty much just out of control and lots of small squash, it doesn't hurt to trim it back about one third. Every third of a vine trim it down to the main vine and then that way the remaining vines will concentrate on producing larger squash but whether you prune it or not, you're going to have lots of squash whenever you plant a squash plant. -Birdy