used growbag and container compost

Hello Yellowbelly,
Mix it up to a dry state and top dress your lawn with it.

I recycle my bought compost when it has been used - I put it in pots with bulbs, or store it in sacks until the spring when I mix it with my home-produced compost and long activing fertilizer to use it for another season. As long as you haven't got any nasty plant disease, this is fine

I was just about to ask this very question on re-using last season's container compost. All I would add is questioning the number of times or seasons I can do that.....?

I would only use it once to avoid follow on of pests and diseases.