Last year, I lost a lot of squash to cutworms. Even after the seedlings matured into 12-foot vine, the cutworms still got at them, splitting the vines near the roots and killing off squash plant after squash plant.
All you have to do is take a regular plastic cup (or an old planter cup that seedlings come in). Cut the bottom off so that you have a little collar. Your cut doesn’t have to be too precise or neat. Gingerly slip the collar over your squash seedling vine (you can also use it on tomato and other vegetable seedlings). Bury the bottom of the collar in the soil, leaving a few inches above the soil.
These little collars are great because they keep water near the roots, protect the seedlings from wind, and deter cutworms.