We have a few flats of tomatoes and peppers started in the greenhouse I put up in the basement. They're doing great, should be big and strong when it comes time to put them out to harden.
Grass clippings are great if they're used in a balance. Jamie has a big garden, small amount of clippings, and he uses leaves and other organic matter to mulch.
Folks with raised beds tend to put a whole garbage bag of clippings around one plant. It's great for the first year because the grass doesn't break down so much. The following year there's so much free nitrogen that plants grow huge and fruit very little.
Go easy on the grass clippings, B. A little is great, too much is not great.