I don't use a COW, but I find that if I put wet castings -- worms and all if necessary -- out on a tarp to dry for a couple of days, the sticky clay-like mess transforms into fluffy castings.

Good luck
Mariann

I have quite a few COW's up for 4 years now. When my lower tray is very dense with vermicompost, I dump the material into a rubbermaid type tote, with holes drilled for ventilation. This lets it finish off even further and dry out, as no drainage is coming in from above. The slight drying out and finishing of this materail will give you the casting "fluffiness" you are looking for. I have kept these holding bins for a long time and as long as there is some ventilation and a top on, it stays nice and properly moist for a long time, (perhaps years). Some worms will still be found in this material and can be moved into a working bin, if you wish. The COW's work well, but not exactly as they are touted. I would not add any material (paper) to a casting filled tray, for as you have already witnessed, it just adds some new material that needs to decompose.

OOPS! Too late. Maybe I should split them into two trays, let them progress a while, and then harvest the castings and combine what's left. If the worms are more or less top feeders, then perhaps two trays would be better- more surface area?
Thanks Susan and Kitten for your help.

Maggie

With a COW you need to add a lot of DRY bedding to the working tray to prevent too much moisture from accumulating in the whole system. I add more dry shredded newspaper to the top tray every week, or whenever the existing paper is not quite adequate to cover the food. All this dry paper will absorb some of the moisture that would otherwise trickle down into your lower tray and turn it to mud. With that lower tray, you can fluff it up periodically to aerate it (without adding anything). The worms moving through it will also churn and aerate it, as long as there's not too much moisture coming down from above. I leave the lowest tray 6-9 months before harvesting, at which point it has a nice damp soil-like texture. You can put it on the top exposed to light and scrape off the castings gradually. As you do, the alarmed worms will go below-decks.