This is another port of one of my newsletter articles into Steemit.

One of the first things every new worm farmers ask is what to feed and what not to feed their worms. A lot of resources are available regarding this subject and it's usually the same:

Feed your worms most fruits and veggies scraps with few exceptions such as onions, garlic, chili, pineapple, tomatoes, citruses...
Don't feed your worms scraps such as meat, dairy products, bread, cooked meal etc...

Does it really mean worms cannot eat meat, dairy products etc?

Well not exactly... but first, you need to know that worms don’t really eat the food waste as they don’t have teeth. It’s the bacteria and other microorganisms in the worm bin that will start consuming the waste and break it down. The worms will then come in and suck in the soften food. Some bacteria and other microorganisms are thus ingested by the worms along with the soften food waste. Most of the bacteria and microorganisms are digested by the worms, whether or not the actual food is digested is a bit blurry but my guess is at least part of it is.

Back to our question, can’t worms eat those “forbidden” food waste? Or maybe a better question is: is feeding worms meat, dairy etc... an absolute no no

Worms can ingest those food waste after it has been broken down by bacteria and other microorganisms (again). However, it is highly recommended to avoid those types of food, the two main reasons are:

Some food scraps can be harmful to the worms. Citrus, for example, is said to irritate the worm skin and pineapple contains a meat tenderizer chemical which is claimed to harm the worms.
Other types (protein rich) will turn bad quickly. Meat, for example, only needs few days to start producing offensive odor and attract vermin and other pests such as flies or rats and mice which can also introduce pathogens to the worm bin. This situation is worsened by the fact that most domestic worm bins are small, enclosed and not properly aerated systems. We need to remember that worms don't start eating food scraps until they have been broken down by bacteria and other micro-organisms. Worms don't have teeth, they need the food to be soft for them to start "sucking" on it. It takes usually about one week for the bacteria to break down the food down, then the worms get in and take another week to consume the food.

That being said, there have been videos showing worms devouring lemons fallen on the ground or pineapple fed in large quantity as part of an experiment in a large worm bin. I, personally, never had any issues with adding all types of fruits and vegetables to my worm bins.

Now, I'm NOT suggesting you dump all your meat, pineapple, citrus etc... in your worm bin because you will most likely kill all your worms.

The purpose of this article is to understand something else: relative quantity/volume.

The advice to avoid food types above is usually made to prevent the new worm farmers from failure followed by disappointment and then giving up. But as you get more experienced, you might start noticing some worms chomping on pieces of oranges or pineapple that have accidentally made their way into the worm food.

What can turn "bad" food waste safe for the worms?

A safe place: if fed with potentially harmful food scraps, then, always provide a lot of safe/neutral place for the worms to retreat to while the bacteria will break down the scraps. Or just reduce the amount of the scraps and place them in a corner and observe the behavior of the worms.
Neutralise the pH: the acidity of some food scraps can be neutralized by the presence of other non-acidic food scraps and the addition of a large quantity (same or twice the volume) of dry bedding material that will "dilute" it. Additionally, adding material rich in calcium carbonate such as finely ground eggshells or garden lime will help raise the pH (reduce acidity). Be careful, however, and avoid some alkaline materials that are caustic and will burn the worms, those are materials such as slack lime (calcium hydroxide also called builder’s lime) or ash.
Add a lot of bedding material (cardboard, newspaper etc...) and with time bacteria will break down the scraps and the harmful compounds or they will leach out and get diluted in the bedding material.

How to apply this to the feeding process?

Start a new bin with 10 to 20 cm (4 to 8 inches). Add a handful of garden lime (pH buffer) and a handful of finished compost, vermicompost or soil to innoculate with beneficial micro-organisms. This would be the initial safe space with some bacteria to start breaking down the scraps. Add some food scraps, the same weight as your worms, on one half and add the worms to the other half.

The pocket feeding technique is one safe technique to use for a small enclosed system. You feed half of the bin or a corner each week and move to the next available unfed area the week after. New scraps are taken care of by bacteria while the one-week-old scraps are being consumed by worms. Providing you are not overfeeding (worms eat their weight if food scraps and bedding material per week) there is always a safe place for the worms to retreat to (the one-week-old side). More details on my previous post on How to feed your compost worms

For a larger system that has a deep enough bedding/castings layer, you can feed the whole surface area to a maximum thickness of 5cm (2") to avoid too much heat due to the composting process. The photograph at the top shows a feeding for Gargantua (that is how I call my homemade Continuous Flow Through worm bin). Its dimension is 100 x 60 x 60 cm (3.3 x 2 x 2 ft) and at the time of the taking of the photograph, it was filled to 18". So in terms of safe place, Gargantua has plenty of it. If there ever is anything wrong with the scraps I add, the worms would either migrate horizontally or even vertically and will come back when the scraps are rendered safe by bacteria.

I always use a lot of dry bedding materials (hand torn newspaper or shredded corrugated cardboard). The total volume of bedding material is about once to twice the volume of scraps:

I first mix in the bedding material with the food scraps in a tub, this will absorb any leachate that is already present. I take the opportunity to sprinkle some garden lime. This step is optional but I like to do if if time allows
A good layer of dry bedding will go under the food scraps. This will absorb leachate that will be produced later on as the scraps break down. It will also help "dilute" any acidity from citruses for example. When using bedding material such as corrugated cardboard, being bulky, they will help with better aeration of the system, sustaining more beneficial composting organisms.
I then cover the whole thing with more bedding material or coffee chaff (which acts similarly) as an attempt to control odours and restrict access from flies to the food.

Check that process on the following video:

Conclusion

To summarise, it is all about a quantity/volume relative to the size of your worm bin and total food scraps. In a system like the Can-O-Worms, the Worm Factory or a Rubbermaid self-made bin, half or one lemon (with other food waste and a lot of bedding material) will not be harmful, add one kilo (two pounds) and it you will get a worm soup. It’s all about the volume of “bad” waste relative to the volume of other “good” waste relative to the volume of neutral space in your worm bin.

However, what ever system you have, it is still best to avoid meat, dairy products and other protein-rich waste due to the vermin and pests issues mentioned above, unless you know what you are doing. For those types of waste, I would use Bokashi or Black Solider Fly Larvae that can potentially consume them in a single day.

As usual, if you are overwhelmed with the info, don't hesitate to comment below and I will be happy to clarify any confusion.

Do worms really not eat meat. Understanding relative quantities.

Does it really mean worms cannot eat meat, dairy products etc?

How to apply this to the feeding process?

Conclusion

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