In news:rec.gardens, "Farm1" posted on Sun, 3
Jun 2012 16:47:22 +1000 the following:

I've cut the bottom out of very large plastic pots, drilled very large
holes around the sides of the pots, (so worms can go in and out at will)
submerged the pots almost to the rim in the garden and put a lid on them
with either upside down pot plant saucer or old chrome hub caps. I've
started seom fo them off with mature compost and compost worms and then
thrown in kitchen scraps and I've also started others off with soild and
a mix of compost worms and earth worms.

That sounds like a nice idea... The pot would act as a partial barrier
(except where the holes are) so you get a "slow-release" fertilizer.

Damaeus