There is no problem with placing a second tray even though there is debris in the bottom tray. The bottom tray is not ready for harvest and worms will continue to work in the bottom tray and some will move into the upper tray especially if you place some food in a corner. Also THERE IS NO NEED TO LINE THE SECOND TRAY WITH PAPER. I have never lined a tray after that first time.

I suppose I take this for granted that everyone does this , but if you have a juicer or food processor of some kind the worms can use the material much faster by using the extra step bacteria will break the food down that much faster otherwise the worms will be just be sitting there tapping there fingers waiting for that to happen,, just a thought.

Isn't it easier for the worms to migrate if the new tray is *below* the currently in-use tray? That's what I do anyway. and I leave the top off the upper tray to encourage them to move down, away from the light. They love baked sweet potatoes!! Cheap worm food, imo. Also banana peels torn in thin strips. Watermelon and watermelon rind. I place these in the tray I want the worms to migrate to and they follow their noses.....or whatever.

I don't think the force of gravity is that big an influence on what direction the worms travel. Some people have them migrate up. Some people have them migrate down. Some people have them migrate laterally. It doesn't matter. Up is common because it is what worms do in the wild.

Oh, that's interesting and I see your point. Thanks!

Never used a stacking tray system before but this is thought provoking. Sure worms in nature migrate upwards as this is where new material is added but it begs the question as to if nature always knows best.

If you put your new tray in the second from the top position and the last active one on top it would help to stabilize both temperature and moisture in the current feeding tray. You could also allow the top tray to dry which would further encourage the worms there to move into the new digs.

Yes, that would be an advantage of downward migration.

I hink most wormers agree to the theory that red wigglers prefer to stay in the top 6" of material but then again they will go where the food is.

Exactly, but what are the mechanics behind their desire to be in the top six inches? Is it because new organic material naturally deposits itself there so if their world goes topsy turvy would they simply migrate down or are there other things at play like pressure or light? Light seems like it would be another advantage of encouraging the masses to assemble in the second tray down as it would surely be darker.

Only reasons I can think of that could be non optimal would be the extra effort of having to remove the top try for feeding and slight possibility air flow may be less than stellar.

All just guesses here on my part, bin wormin is interesting to me and I am probably gonna set some up this summer but come cold weather they will be introduced into my "Free the Worm" movement.

Concerning the worm factory Im seeing more and more when It comes time to harvest a tray and add a new one[feeding tray] its better to not be in any great hurry to add food to that top feeding tray, since there is still a lot of food yet in the tray below it . Dont try and draw the worms up quicker by adding new food or not either way works,, just sayin.

The book that came with mine indicates you should wait until most of the food in the current feed tray is consumed before adding another. On the other hand, it also implies that you may have worms in multiple trays at the same time working on different stages of decomp. I'm thinking of adding second tray with bedding but no food as a way to try to get rid of the fruit flies I have spawned.

Other factors: Worms don't like to live in their own castings (though some seem to) and oxygen is more available near the surface.

Yes, you will find worms throughout your system, but the bulk of them tend to want to migrate away from their castings.

My thinking in the downward migration is that in nature, they are wiggling up in dirt. With the trays, they will need to negotiate plastic sides. Sure they can, but wouldn't it be easier to just wriggle through the mesh at the bottom and drop to the lower tray? it's all good, but that's what I was thinking when visualizing the worms going up.

The worms are able t go up because the upper tray is sitting directly on the VC in the lower tray.

that's not what happens here, for me. The one tray is not so full that it touches the new, upper tray. There's the difference I think.

I thought the idea of multiple levels was to increase the surface area. Thus each bin is "the top six inches". I agree with putting a tray ready to be harvested on top for a little bit of time. I agree with not having to lift trays in order to do a regularly scheduled feeding.

If a person only has 1 or 2 trays going there is really no problem. In my situation I have 5 trays going so when the bottom tray is ready to be harvested obviously the 3 or 4 trays above it will have some unprocessed material in it and it will continue in this manner although the only tray I will put any food in will be the top tray. In the meantime there is still worms at work in the middle trays. Once the bottom tray has been harvested back to the top it goes with all new bedding along with some old newspaper from the previous top tray, therefore the name of the bin "factory 360" as a rotation has just been done. So therefore the middle trays will always have worms in them working on the yet to be processed material. Hope this makes some sense to some as Im totally confused by now :-).

I really should ramp up my feeding and worm poop harvesting. I'm a bit negligent as much of my kitchen scraps go to the barrel composter out in the yard. I like the worm castings for potted veggies, especially the strawberries which respond *really well* to the addition of some castings from time to time. Being in Phoenix, I don't have all that many container plants as the soil dries out so quickly here. I use compost from the barrels in the garden beds.

I've learned A LOT from this discussion. Thanks for all the help worm lovin' buddies!!

In response to the above question about upward migration: My worms are able to climb plastic just fine. In both my worm factory and my rubbermaid bin, they are frequently crawling upside down on the plastic lid. But as sbryce _gw mentions above, the bottom of each tray is sitting on top of the bedding/compost in the bin below. Heck, based on the tray I'm about to add, some of the shreds even hang out of the top bin into the bottom.