Moisture & Food Quantity Questions

These questions come from Beth.

Thank you for the informative blog! I am new to worm
composting (about 1 month) and have set my bin up following your
YouTube video for the ‘deluxe’ bin (2 rubbermaid bins with the
recommended number of holes drilled into the sides, bottom and cover
of the top bin). I have 4 questions and would be grateful for your

1) The inside of the bin is very moist – so moist that when I remove
the lid it is dripping with condensation. The sides of the bin are
also covered with condensation and there are worms clinging to the
walls of the bin (and some have escaped onto the floor where they
have sadly met their demise by drying out). This seems like way too
much moisture. What is the ideal level of moisture? What’s the best
way to get the moisture down at this point? I have checked the lower
bin and there is very small amount of water there as well.

2) How much food can I add to the bin at a time? I have a family of
4 including me. We eat plenty of fresh foods, but I don’t think we
eat more of them than most people. Should I be able to add all our
scraps to one bin, or would this be too much for the 1 pound of worms
I have in there?

3) Is it normal to smell an unpleasant odor when opening the bin? I
have not added any meat or oily foods, but still, the bin smells
like, well, garbage! 🙂

4) I see some long furry looking white stuff growing on some of the
food scraps. Is this OK?

Thanks very much for your help and this terrific resource.

Thanks Beth! Let’s see if I can help you out here.

1) Condensation on the lid and sides of the bin is totally normal, and not really something to worry about. Worms up on the underside of the lid and sides of the bin is also very normal (as long as it is only a few – if it is a LOT of worms there is likely something wrong). Worms crawling out of the bin and onto the floor however is not normal – if conditions in the bin are too their liking worms would much rather stay where it is nice and moist rather than venture out into the dry air. Once in awhile you might see the odd curious worm venturing out, but if it is ever more than one at once I would suspect something going bad in the bin.

Composting worms LOVE it wet, and will be happy as long as there is still oxygen available. Given the fact that there is only a little water down in the reservoir below, I’d say you are ok on the moisture front. If the bin didn’t have drainage holes there would be a much greater chance of excess moisture build-up. Still, if you are hoping to dry things up a little and keep the worms down below you might want to add some fresh, dry bedding on top of your bin contents. The best material would be something very absorbent. I particularly love the cardboard used to make egg cartons and drink holders (the throw-away kind, from coffee shops and fast food restaurants). I’ve added this material to wet bins and it worked very well – absorbing condensation and keep the worms down. Of course, if there is something nasty going on in your bedding already this might not help much. More on that in a minute.

2) I would predict that your family of four produces quite a bit more waste than can be handled by a pound of worms – ESPECIALLY when just starting out. A brand new worm bin goes through an adjustment period before the worms are performing at their best – and even then they wouldn’t likely be able to handle this much. My wife and I produce more food waste than could be handled by a single small worm bin. Luckily I have a variety of different bins, and other options (like bokashi buckets, backyard composters etc). It is hard to give a definitive answer as far as what amount your bin should be able to handle. There are so many factors coming into play. The best way to find out is simply by testing your own system. If you set up your bin exactly the way I demonstrate in the video (ie. food is mixed in with bedding before adding worms) you don’t really need to add much food to the bin for awhile. Simply monitor the waste that is in the bin, and as you see it disappearing start to add more (a little bit at a time). Too much food in a worm bin can really create problems.

3) This question definitely makes me think there is too much food in your bin (thus explaining why your worms are venturing elsewhere). A well-balanced worm bin should definitely not smell like garbage. It should be essentially odourless. Bad odours are typically caused by anaerobic decomposition of organic wastes – something that can happen quite readily when lots of wet food waste sits in any one spot for an extended period. I would definitely recommend mixing a fair bit of fresh dry bedding into your bin (do this before adding the layer of bedding over top I suggested earlier) – this will help absorb excess moisture and help air to circulate through the bin materials more easily. The bad odours may persist for a little while, but if you stop adding food they should disappear before too long. I’d recommend setting up a separate food scrap holding container if at all possible. A bucket should work fairly well. Simply add a thick layer of dry bedding at the bottom, then add your scraps as they become available (mixing in a little bedding each time you add any). This allows your wastes to age (worms will process them more quickly) and also ensures that you won’t add too much food to your bin at once. Once the weather outside is decent (maybe it already is where you live) just set up an outdoor compost bin as well so you have some place to put excess food waste should it start to pile up on you.

4) The ‘furry’ looking stuff is just some type of fungus – I wouldn’t worry about it too much. It is common to see lots of fungal growth in a bin when too much food is added. It can be an indication of acidic conditions (which can be brought about via anaerobic processes mentioned above), since fungi prefer somewhat acidic conditions in general. Again, I’d recommend mixing in a decent amount of new (dry) bedding and holding off from feeding your worms for awhile. If you eat eggs you might want to keep your shells and grind them up for your bin as well.

Anyway Beth – hope this helps! Let me know if you have any other questions (feel free to comment on this post).


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    • Mary
    • March 21, 2008


    I have the same problem as Beth. The bin also has pot worms. How do I get rid of them prior to harvesting the castings? If the ph level comes back to normal will the pot worms disappear? Should I add natural charcol to sweeten the environment?


    • Bentley
    • March 21, 2008

    I would simply harvest the castings then let them sit for awhile to partially dry out. Without any food supply the pot worms should disappear pretty quickly. You may also want to mix in some dry, absorbent bedding to help wick up extra moisture.


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