Believe I can use empty compost bags instead of crocks to help drainage in my containers
By Jenniegill
Cornwall,
United Kingdom 
Should I shred or crumple the bags ?
12 Jul, 2009
Answers
The weight of compost in the containers will compress the compost bags, even shredded, and these will block the drainage holes.
Maccrimmon's suggestion of broken polystyrene is a good one.
12 Jul, 2009
never used compost bags Jenniegill , I know youcan use polystirene packing broke up into bits , it's light in the pots compared to crocks.
12 Jul, 2009