Previously posted on our forum the following post form March 2009 asks is there any use for old composting bin contents.
I have two worm bins, one of which is fine and healthy, but the other unfortunately needs to be started afresh. It’s about two thirds full, the contents are dark brown but not smelly, but very wet – well, sodden really. I didn’t drain it often enough, I didn’t put in enough paper and the whole thing became wet and therefore anaerobic and that’s why my old worms died. The fault and associated guilt are all mine, and I promise not to let it happen again! My question is, can I reuse the contents? It’s surely full of microorganisms which I can’t quite bring myself to just get rid of, and I also don’t have a garden to just tip it out onto to start again. I don’t propose, obviously, to just chuck it all into a new worm environment – I thought I could drain it, then mix in paper/cardboard until it’s dry enough to store in an old compost bag or bucket, then start the bin anew and just add the old stuff a little at a time over a long period. I’m also wondering whether it could be of use to feed or mulch very hungry plants that need a lot of moisture like courgettes or potatoes (more of a gardening question I know, but if you don’t ask you don’t get), or whether I should treat it as poisonous and find some discreet place to get rid of it. I’d very much appreciate any ideas or advice.
From the details it does sound as if the “compost” was heading towards being anaerobic, if it was fully anaerobic it would have an unpleasant smell about it, heading to being anaerobic could well have killed off the worms particularly if your wormery is of a design with a clamp down lid designed to prevent worms from leaving whatever the conditions! if not then it is more likely the deteriorating conditions would have caused the worms to leave, end result is no worms and dubious compost.
If the compost is truly anaerobic the micro-organisms (and gasses) will be harmful to worms and would do your plants no favours either, best disposed of the best way you can. If it does not smell then treating it as you suggest and feeding back to a new worm system should cause them no problems, use your nose for a decision!
See our advice sheet about Liquid Feed From a Wormery for more about aerobic and anaerobic conditions.