Worm Factory Questions

Some questions from Becky:

1. I have the original worm factory with 16″ trays. How may worms can
I keep in a tray?

2. How much bedding should I expect the worms to consume before
feeding again or adding another tray? I am using office paper from the

3. How wet should the trays really be with red wigglers? My
“processing area” between layers of bedding are much darker and dryer
than in your photos. Like damp coffee grounds.

4. White mites. Have found clusters on individual dead worms 3x in 2
weeks and removed them from the bin. How many are normal and how
should I deal with them?

Thanks for everything!

Hi Becky,
Let me start by saying that my answers are simply based on my own experiences/preferences and reading on the subject – not necessarily what the kind folks at Nature’s Footprint would recommend. You may want to consult with them as well.

1) I definitely wouldn’t think in terms of a specific number of worms per tray. Red Worms are pretty good at self-regulating their numbers so they will grow to whatever capacity they feel comfortable with and then slow down reproduction and/or move to other trays etc. My preferred approach is to do one tray at a time, gradually moving up as trays become filled and fairly well processed – so my focus is more on the amount of processed material (and overall volume of material) than on the number of worms. With my own Worm Factory (360 model) the most trays I’ve had at once is actually only two – although others who are adding materials more regularly than I am will probably move up a bit more quickly than myself.

2) Again, this isn’t quite the perspective from which I would be focusing on the system. There are so many factors at play here, so it would be incredibly difficult to say “after x lb of bedding/food is consumed, you will be ready to add another tray”. I might say something more along the lines of “once a tray is about 1/2 or 3/4 filled with fairly well processed material, add another tray” – but again, this certainly isn’t set in stone by any means. I recommend always keeping your active trays well stocked with bedding, except for those you are trying to finish off (ie the lowermost tray). If you make sure there is always a good supply present, you will have no need to worry about adding specific quantities on a regular basis etc.

Regarding how often to feed – my recommendation is ALWAYS, “let the worms be your guide”. If you feed based on expected processing ability (especially if using optimistic/unrealistic projections), you’re almost always going to end up disappointed and likely with some serious issues in your bin. I’ve come to develop a certain “feel” for when I can feed again – but of course this is pretty vague and wishy-washy, so it’s not going to be of any use to a new vermicomposter. Try holding off on feeding until the vast majority of the food material is no longer recognizable – don’t worry so much about the bedding since it will be processed much more slowly – like I said, just make sure to maintain a decent amount of it in your working trays at all times.

3) My preference is to keep the contents nice a moist – but not so moist that any significant quantity of leachate is accumulating in the reservoir. If you picked the material up, liquid wouldn’t drip out – but if you squeezed it a fair amount likely would. Red Worms LOVE wet – but still oxygenated – conditions. If they seem to be thriving in your bin, I wouldn’t be too concerned (although your mention of dead worms is a bit of a red flag – will talk more about this in the next response).

4) It’s very common for new vermicomposters to link the presence of certain organisms in their worm bins with various “bad” things that are happening with the worms. eg “worms are dying, there are lots of mites…therefore, mites must be responsible for worms dying”
I really, really try hard to help people see things differently (I jokingly refer to myself as a “critter advocate”), since most often it’s a case of “barking up the wrong tree”!

Focus instead on the worm bin environment/habitat – and specifically, on the key requirements of the worms. They need oxygen (and on a closely related note, good air flow), moisture, darkness, and a well-balanced habitat (lots of carbon-rich bedding material, and not TOO much nitrogen-rich material). If you meet all their requirements, you very rarely need to be concerned with other critters in the system.

Like I said above, the fact that you are finding dead worms in your bin is a red flag for me – tells me something is definitely going wrong in your bin. I almost never find dead worms – but when I do (as was the case in my first “Euros vs Reds Head to Head Challenge” bin! DOH!) there is something really “off”. When the balance shifts away from favorable Red Worm conditions it is VERY common to see other organisms expand in numbers and appear to be “taking over”, “causing harm” etc. White mites are definitely one of those creatures – they are opportunistic scavengers, and they even seem to feed on worms that are not quite dead yet (kinda like the vultures of the vermicomposting world – but with a flair for rotten vegetarian meals as well! lol). I can remember some of my early vermicomposting experiments in university (back when I was still a bit wet behind the ears), where I attempted to feed Red Worms all manner of food materials – often adding far too much at once. Let me assure you, I saw a lot of worm carnage back then, and a LOT of white mites!

Bottom-line, get your system back in balance and you should see a reduction in the number of these mites. In your case, it may be a matter of feeding a bit less and improving the air flow – although, without more details about your bin, it’s hard to say for sure.

Hope this helps!

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    • Becky
    • April 2, 2012

    Thank you for your quick response 🙂
    I have only had the worms for about two weeks, so I am VERY new to this.

    Update on the mites: I waited about a week since their last feeding before feeding them again and there were no noticeable mites or dead worms in the bin. I think the dead worms may have just been the ones traumatized by being shipped to me? Everyone seemed active and quickly moved down into the bin when I opened it and they were exposed to the light. Also there are dozens of cocoons.

    I have 2# of worms and gave them 2 1/2# of fruit & vegetable scraps this week, (frozen then thawed) mixed with the layer of moist bedding that was in the top of the tray. Then I added a new 2″ layer of shredded paper/cardboard on top of that. It is very hard for me to tell how quickly they are processing the food I give them because I have been putting it through the food processor and the coffee grounds in the food make it all very dark like the existing castings. I am going on the assumption that they will process the bedding if the food is all gone.

    Also, I have “modified” my use of the bin based on another reader’s comments. I was concerned about air flow, had fruit flies, and the worms kept getting down into the leachate tray. I removed the leachate tray and spout from the bottom tray of the system. This bottom tray is now like the remaining trays, with solid sides and a “screen” bottom. I placed a single layer of an old bed sheet on the top of it, set my working tray into it, then placed another single layer of an old bed sheet over the working tray and placed an empty tray on top. Every few days, I mist the top layer of bedding with a spray bottle of clean water.
    ***results*** I have NO fruit flies/gnats, no odor, no dead worms, no noticible mites in the bin, lots of worm activity, lots of cocoons. Also, pure worm castings seem to sift down onto the bottom bed sheet which I poured into a bucket of water for worm tea. Maybe I’m just lucky this week, maybe I’m onto something! I’ll keep you posted on the progress.

    • Laurel
    • April 18, 2012

    Have followed your advice in starting my bin in February. “My boys” are thriving and black gold is building. I have found they love shredded paper and cardboard, coffee grounds, tea leaves and crushed egg shells. I check their “feed” every few days and give the whole bin a good stir about once a week, while keeping a moist upper layer of shredded paper.
    Question: how exactly do I harvest the compost to use in my garden….

    • Bentley
    • April 18, 2012

    BECKY – thanks for the update (sorry for the delay responding)!!

    LAUREL – you may want to check out this blog post:
    It outlines how I did my first harvest.

    • Laurel
    • April 19, 2012

    Thanks Bentley,
    My bin is nothing fancy…just a rubbermaid bin with holes drilled. I guess I’ll have to make a screen of some sort and scoop out the compost a bit at a time, returning any “reds” to the original bin and building it back up.
    I so appreciate your website in helping to keep me on the right track.

    • amy narewski
    • September 29, 2016

    Hi there, just recently had worms given to me and am now thinking of putting the leaves of the laurel (bay leaves) into the bin as bedding. Are the poisonous for the worms? I read the ca be used as pesticides; so I am a little worried.

    • Dave
    • January 1, 2018

    Hi, I was reading your answers to Becky and admire how you worded everything. I have been worming for a few years now, and had to learn most everything the hard way. You and I seem to feel the same about how it should be done. Tanx for the enlightenment.


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