Q20361: I think the idea is to put a composter on soil, preferably loosened up first, because that encourages worms to enter the material in the composter. If you have to put it on concrete try to gather some worms and throw them into the material to get it going. Worms will tend to gather where there is anything wet - eg wet sacking, wet carpet, wet cardboard, etc.

Ordinary garden worms won't survive in a composter, what you should do is go to your local fishing bait shop and ask for dendrobaena worms. You may be better off investing in a wormery instead!

We have a compost heap on concrete. Not advocating this, but it works for us for last 23 years, and in the garden before this one. I have noticed there is a crevice just in front of the heap and the worms pop in and out of this slot. I put leaves under a bucket, under the waterbutt tap, and there are nearly always worms there when I lift the bucket. They are press ganged into the heap and we occasionally get the small red worms from Wiggly Wagglers too. There is an occasional donation of diluted urine too. My brother says this is done directly on his allotment!!!!!!!

We answered this question recently and at length too. If possible have your compost bin on soil. If for whatever reason this is not possible it is better to have a compost bin on concrete than no bin at all.