The runoff from a worm bin really should not be used on any plant. It is excess moisture that has perculated through undigested feedstock and therefore could be contaminated. Actually, you want to work toward no leachate at all. I have only added compost when I re-pot my houseplants. An inch on the bo0ttom and (after cutting away extra roots) add a 1/4-1/2 inch around the edge. Making aerated compost tea is the best alternative to leachate.
