They will love the compost, it has rotted for a good year now, should be full of organic goodness. Only issue for indoor crops is the living things that come along with it! Worms, flies, beetles, gnats, spiders, centipedes, mites, earwigs, etc etc etc. Diatomaceous earth is great but if you bring in a zoo, who knows what could happen! For outdoor plants not much beats good compost.
BTW I have an outdoor plant for the first time. Well, I've done a greenhouse before, but this is the first in an open garden. It's in the back yard where nobody will see it, unless they're at a very specific point on the sidewalk, and looking at the right angle, with good eyesight. But if my tomatoes grow up a little, they'll hide it, I think. Then again, dude, it's growing pretty quick. They really like it outside, eh? Gonna be 105F this week though, not sure how it's going to do. I'll just keep it watered and hope for the best. Same with the matoes! You having a heat wave too?