Q.3 questions about spreading plastic over areas to be planted in the spring.
I’ve heard that spreading plastic sheeting over an area that I want to plant next year is an effective way to kill grass & weeds over the winter (the heat created & contained kills everything). Is this true? If so, would clear plastic be better since it will let light through and theoretically increase the retained heat? Lastly, would this also kill any beneficial nutrients, worms, etc.?

Certified GKH Gardening Expert
It works better in the summer, but you should have some success over winter too. Clear plastic works best.
It will kill beneficial bacteria ONLY in that spot. This means that once the plastic is removed, they will return from surrounding areas. Worms will not stick around to get hot. They will go elsewhere until the plastic is lifted as well.
This is a very safe and effective way to prepare a garden spot.