The idea is for the worms to finish that first tray. You can add shredded paper and some food in a second tray but the surface of the bottom tray should touch the bottom of the second tray to coax them to move up. However, just like kids, they don't always do what's expected of them and just go their merry way. Don't bother picking them up. I did that and just wasted my time.

3 weeks is not a long time but your tray is looking good. You're getting there, just be patient a bit longer. When I had my WF360, there were always worms staying in the lower trays. Not sure if those were the same worms or other worms crawling back and forth. The lower trays will always be more damp than the one above it and that's what the worms like I guess.

Karen, don't worry your worms are doing fine. Like Otis said the worms will gradually move up into the next tray as the food supply becomes depleted in the lower tray. Your lower tray (in the pic) looks like it still has food/shredded paper in it and the worms are still working on it. Don't forget, the worms don't really eat the food until it begins to decompose. Even when they do start to favour your newest tray you will always find some lingering in the bottom tray. Just make sure the upper tray contacts the bottom tray so they can migrate upwards easily.

When the bottom tray looks like it's just castings and you want to harvest it try moving the bottom tray to the top and put in in a bright spot with the lid off. That way whatever worms are still in that tray will tend to move down away from the light into the active tray below. At that point I've found you can usually remove most of the castings from that tray without coming across many worms. If the worms seem slow to go down into the active tray just scrape off a few castings at a time. Once you start to see some worms, stop scraping for a bit and give them a chance to continue moving into the lower tray.

Hope that makes sense! Have fun and good luck with your worms!!

Harry

There will always be some that don't get the message. I've been remiss in harvesting the lowest tray. Should have harvested it 6 months ago. It is a mucky mess but there are still 100s of worms in it.

How many trays should I use? Mine came with four. I have shredded paper with a sprinkle of DE on the top tray after I saw too many fruit flies. I’m wondering if I should purchase additional trays or just use the four it came with not having the top tray full of paper and DE. The flies are gone so I could get rid of the top paper tray.