The uniformity of particle size and the darkening colour are good indicators of worm casings. But the best is to just simply check to see if worms are mating and making coccoons, check to see that more coccoons have been made each day. A cardboard template laid over a few areas is an easy way to see if you can count more coccoons. Check to see worms are coupled up making a coccoon each, but don't disturb for long.
No mating signs means the food is insufficient or the pH is wrong, as pH is the next biggest thing that goes wrong after too much cast. You are running a bacteria farm primarily, worms have no bacteria naturally like every other animal, so pay attention to pH first or the wrong bacteria will grow and the worms can not use them to break down the food first, next keep moisture levels high and constant, once again to peak bacteria, keep light out primarily for the bacteria as well. Peak the bacteria count and you peak worm growth, which simply responds to an apparent over supply of suitable food. So add large quantities of AG lime to keep the pH up to around 6.5 to 7.5 ideally, peak. Correct bacteria is best maintained in that range.
In true commercial growing you really need a Separator to harvest the 40 kgs in the fastest way, our separators have proven to be very popular.
Offered by Darryl.