Until recently I had never succeeded in cultivating springtails in large enough quantities for them to be of use as a food source for my Dendrobates or Mantella, though they are always in my vivaria.  At Frog Day in Holland in April, 1996 I bought a culture contained in an ice cream-type tub, which was teeming with springtails.  From this I was able to establish how it had been made.  The important feature would seem to be the form of the medium.  This was peat, sterilised in a microwave and then compressed until it was a very solid block (easy to achieve with my weight!).  The culture should then be seeded with a substantial number of springtails and fed regularly with suitably small amounts of boiled potato or flaked fishfood.  The springtails can be extracted by holding the peat 'block' in place with a finger while tapping them out.  Alternatively they can be floated off by drowning the culture.  However, the culture needs then to be re-started.  With six cultures on the go at any one time, I even feed them to my larger frogs. 
Mick Bajcar