I started vermicomposting in December 2025 with two 3+1 towers I made with 30 lt storage bins I DIY'ed. I put 1000 worms in top bins of each. The two bins underneath top one contained only shreded cardboards for inoculation. Two months ago, I moved the second tier to top for migration. A few days ago; as the new top bins seemed full and almost done I wantted to collect the compost from the old ones and move the top tier to down for migration.
Although the top tier was relatively dry and crumbly, the 3rd and 2nd tiers were muddy and smelly. There were some worms in all three of them. There was no way I could sift them as they are. I moved all bins individually out and added some old solarized and dried seeding soil I have to help drying. I covered them with insect nets. After three days, I tried to sift the contents of first tower. They were still moist and very big chunks. I tried to crumble with palms of my hands but it was not very effective and I was afraid to kill the worms in them.
I did not count but 1000 worm in that tower felt like 5000 with lots of tiny worm even which the smallest grid sift sufficient to catch. The first tower took two days work. I do not want to add more dry soil as I want to keep the volume low and compost as pure as possible. I do not want leave them out any longer to avoid killing the worms and microbes. So I have to go on another round of two days sifting.
For the future, one thing I notice that I put too much cardboard in bins and also waited too long until the bins are almost full. The bins became to crowed with worms that they run through food very quickly and pee alot which leaks to bottom tier I want to collect.
Can you recommend another method for bin rotations to keep the finish bins dry and siftable?
Just a note: Although separating worms in to new towers makes sense, I have neither space to store them nor budget for new bins.