When we were first reviving our garden and lifting the pebbles (New Year New Garden) I found a lot of earthworms in the soil whilst digging (surprising since we have such terrible heavy clay). I wanted to incorporate earthworms directly into my raised beds rather than waiting for them to come up. As we lifted and saved more top soil I collected more worms and stored them until the beds were ready (New Year New Garden update).
I had read that if you introduce worms straight into new soil they can get a shock and die as there is not the same mini-biome as they are used to. So I decided to create my own worm colonies where the worms could live until they felt fine to leave. You can do this too with bought worms if you are not collecting them from the garden like I was.
The benefit of this method is two-fold – if you have worms and just spread them on the soil to improve it – this will most likely just improve the bird’s diet before all the worms can make their way underground (especially in clay soil or hot/cold conditions) so in a colony you are keeping the worms safe. Two; if you have any worm eggs in the soil they came with it will give them time to hatch and live in your soil along with the parents. You could just dig a hole and plonk them in but they may die if they are not used to the soil. It also means your soil gets a dose of worm castings before the worms leave the box.
First get a box (or some cardboard) we happen to drink scotch so had some very conveniently shaped boxes arrive recently but they could be any shape as long as they are not too big and fit your worms/soil snugly.
Then get your worms and fill up the boxes
If you are using cardboard and do not want any tape left in your garden (after the cardboard decays) then you can put the loose cardboard into a box shape and use the soil to hold it in place. Also if the box is flimsy you might want to place it in the position before filling it.
Then put the lid on and cover with soil
Make sure the soil is moist – if it is not going to rain then water in and make sure the soil is moist for at least a couple of weeks. The cardboard will absorb and break down and the worms will eat their way out into the soil.