How do you add compost and manure to containers and raised gardens?I assume you have to take some of the old stuff out first? I have a few large rubber maid containers that need some fresh compost and manure added, I didn't add anything last year so the dirt/ compost is two years old. Not loft of room from the top. Would be a huge job to dump out completely and refill. Should I just take some off the top and add some, maybe 6-12 inches?

What about for raised beds? I'm building two and was just wondering, for maintenance, how to continue adding manure and compost to an area that only can only hold a certain volume before it overflows, unlike gardening in the ground.