This question comes from Peter. He is a little concerned about some white fungi growing on his worm bin bedding.

I used damp cardboard as bedding material. But after some
time, I notice the growth of white moldy substance on some pieces of
damp cardboard. Can you please tell me what is the cause please? I
fed my worms with freshly chopped vegetables like cabbage, amaranth,
soybean pulp, etc.

Hi Peter,
It is important to remember that inside your worm bin is a complex ecosystem, chock full of countless varieties of microorganisms, such as fungi, bacteria, protozoans – along with many larger creatures, such as mites, nematodes, and of course the worms themselves. You may not see a lot of these organisms most of the time, but occasionally some of them will make their presence known when conditions are really to their liking.

This ecosystem is vitally important for the proper functioning of a worm bin. If you’ve ever tried to add worms to a totally new worm bin containing only moistened bedding along with some fresh food scraps, you may know that they often try to escape – this is why I recommend aging the bin before adding the worms. This way, by the time the worms are added there will be loads of microbes for them to feed on.

In your case, I would guess that some type of fungi (many different species can be white and moldy in appearance) is simply feeding on the cardboard soaked in the juices from the plant materials you’ve been adding. I definitely wouldn’t be concerned about this, unless of course it completely takes over the bin and causes the worms to want to escape (I have yet to see anything like that happen – I always view a decent amount of mycelial growth as a good thing).

One thing you would want to avoid is excess growth of green or black molds (especially the latter), since inhaling large quantities of their spores isn’t something you want to do on a regular basis. The good news is that large growths of mold only seem to occur when too much food is added, and when certain types of food are added. For example, if you added multiple slices of bread and simply left them to sit at the top of your bin there is a good chance they would be covered in mold in no time. In a well balanced system on the other hand, the worms and other bin creatures will keep excess fungal growth in check.

It might not be a bade idea to add a layer of fresh, dry bedding over top of the materials in your bin – this helps to keep the microbial growth down below where it belongs.

Hope this helps!

Bentley

[tags]fungi, worm bin, worm composting, vermicomposting, mycelium, food waste, ecosystem, bacteria, microorganisms[/tags]

Looks like today is going to be another busy ‘Reader Questions’ day. I’ve been getting some really good ones lately and have been enjoying answering them here! This first ‘question’ (which isn’t really a question) comes from Felicia. She has an interesting idea for keeping her bin warm/cool and I thought others might benefit from her creativity.

I would like to start out with European Nightcrawlers in
hopes of raising worms for fishing as well a composting. Today, I
started a plastic bin (10 gallon) with moist peat moss and a small
portion of, coffee grounds, and onion and potato peelings. Since I
live on the outer banks of North Carolina, and it turned cool again
today, I sunk the bin in the sand under my home about 3/4 of the way
up in hopes that it will keep the bin warm in the cool weather and
cool in the warm weather. I added to that about 8 worms from my
garden just to try it out. I have since read your recommendations
against yard worms.

Hi Felicia,
I’ll often recommend in-ground worm bins as a way to help keep worms warmer during colder months, and you are absolutely right – the opposite effect can expected in hot weather. The earth is an excellent insulator and isn’t affected by rapid air temperature changes. Keep the bin under your home is also a great idea since it will provide even more shelter during hot/cold periods.

I especially like your idea since you can pull out the entire bin when you want to harvest castings (although, it will certainly be very heavy) – whereas a truly in-ground system would be quite difficult to work with, assuming you ever wanted to remove worms and/or worm castings.

If your area gets especially cold during winter months you may need to take some extra steps to protect your worms from the cold. You may need a larger system to help generate (and hold) more microbial heat, you may need to sink it further down into the ground, and you might also want to add a thick layer of insulation over top (straw, leaves etc work well).

For your particular bin (the one you described above) I would recommend adding more food waste, and also mixing in some shredded cardboard or newsprint. Peat moss is a good bedding material, but you’ll get better air flow if you also add some other bulkier materials. When first starting a bin you can definitely get away with adding more food scraps – assuming you then leave the bin for awhile before adding your worms. This allows time for lots of microorganisms to colonize the materials and for moisture levels to balance out.

You are right about the garden/yard worms – I definitely don’t recommend adding them to a vermicompost bin. If you system is in direct contact with the soil (i.e. isn’t sealed) plenty of regular earthworms will venture into the lower regions to feed on organic matter, but you won’t find an abundance of them up where the composting worms are. Most regular soil dwelling worms require cooler, less crowded conditions in order to thrive. The worms you added may survive for quite some time, but the chances of them reproducing (assuming they are even the same variety) is slim to none.

Regards,

B.

[tags]worm bin, composter, worm composter, outdoor worm bin, vermicomposting, worm composting, composting worms, earthworms, earth worms, european nightcrawlers, composting[/tags]

A couple great questions from Robyn this evening…

Hi Bentley,
I am brand new to this and very interested. I’ve already begun collecting kitchen scraps and have been reading through your articles. Perhaps I haven’t come upon the right article but some questions that I have now are:

1) you mention a “decent amount” of food scraps to bedding…what would this be — equal amounts? more food scraps than bedding? And also, are these layered or mixed together?

2) How does one know when the compost is “ready”? In other words when is it ready to put on the houseplants? Also, is this kind of compost ok for container gardening, specifically a tomato plant?

Hi Robyn,
I’m glad you asked these questions because I have little doubt that there are others wondering the same thing! Ok, let’s get to it.

1) I know I tend to be rather vague at times – aside from being the sort of person that just kind of ‘wings it’ a lot of the time, I also really feel strongly about the idea that there are no hard and fast rules for these sorts of things. Every worm composting system is different (there are so many variables involved) so I always recommend that people test these things out for themselves.

That being said, I’m not just going to leave you leave you hanging like that. 😆
I would definitely say the amount of food (volume, that is) you add should be less than the amount of bedding added. [NOTE: Just in case anyone is unsure, I should mention that we are talking here about when you start up a new bin (before worms added) NOT when you are adding materials once your worms are in the system.] Remember that the bedding serves as a protective buffer for your system, absorbing excess moisture and helping to keep the overall C:N ratio in a safe zone (if it gets too low, nitrogen tends to be lost as ammonia gas which can harm your worms). I would still recommend adding a large volume of food scraps though – perhaps 1/2 the volume of the bedding. As for mixing or layering – either/or is fine (I’ve done both), but DO make sure there is a layer of pure bedding material at the bottom since this is where the most moisture will tend to accumulate.

[Update – Mar 26/08: I started a new worm bin today and realized that the amount of food scraps I feel comfortable adding is actually closer to the volume of the bedding than I thought – perhaps 3/4. I used a layering system today – 4 layers of bedding (1st and last – nice and thick), and 3 layers of food scraps]

2) This is another example of something for which there are no hard and fast rules. If you are using some sort of flow-through system it is much easier to know when the material is ready since the worms are continually moving towards the zone with the best food resources, leaving the compost material behind. In the case of a stackable system like the ‘Can O Worms’, the idea is that once your last (upper) tray has been added and fills up, the compost in the lowest tray is probably ready to be used.

In the case of a regular worm bin (a plastic tub, for example) it can be a little bit more of a challenge to know when you can start harvesting. My recommendation is to simply wait until a lot of the material in the bin has a dark, soil-like appearance, with no residual food waste or bedding. If your system is sealed (i.e. no drainage holes), the material near the bottom will likely be quite anaerobic (oxygen deprived) and definitely shouldn’t be used right away. I’d suggest dumping out your bin (preferably on a sheet or mat outside) and breaking up the compost with a garden fork, then leaving it to dry out somewhat. The worms will concentrate down below and the compost can gradually be removed until you are left with partially digested materials (and worms), which can be added to a new system (something you should prepare prior to harvesting.

As for worm castings (vermicompost) being used in container gardening – ABSOLUTELY! The beauty of this type of compost is that a little goes a long way. A small handful placed in the hole when you plant each tomato should make a big difference.

Anyway – hope this helps!

B.