Worm Food

When talking about worm food we enter a fairly broad topic. For most worm farmers determining what food source to use really comes down to why you are raising worms and how many worms you have.

Just like us worms need food to survive and composting worms eat many of the same things people do, and lots of things we would never eat. While worms may feed off many of the same foods we do they eat them in a completely different way.

Worms have no teeth so they really don’t break down food by biting pieces off. Instead worms prefer decaying organic matter that is already breaking down. Food is decayed or broken down into a soupy mush by microscopic organisms, microbes. It is this mush of decaying organic matter and microbes that the worms feed on.

Another thing to keep in mind is your worm bin bedding is also a food source, meaning it’s made from organic matter. So worm bedding also decomposes and breaks down into a food source for composting worms. Bedding material such as paper, cardboard, leaves, grasses, black peat, and coconut coir eventually all decompose into a food source for the worms that live in it.

In fact some worm farmers use cardboard as their sole source of worm bedding and food and report their worms do just fine. Cardboard, paper, and peat moss all contain high levels of carbon which provide a good habitat for composting worms.

Food sources the home vermicomposter should avoid are meats, grains, citrus fruit, oils, and non-biodegrable materials, and pet waste.

Home vermicomposters using composting worms to reduce kitchen waste and produce their own vermiculture find that vegetable and fruit matter scraps from the table are just fine. Items such as vegetables, fruit, used coffee grounds, and egg shells are ideal. These food items should be free of grease and fats such as cooking oil and butter. If you live in a rural area and have access to aged cow manure this makes both an excellent bedding and food material.

If you feed your worms kitchen waste consider cutting up the pieces into small pieces, or even running them through the food processor. This will help jump start the decomposition process, smaller pieces break down much more quickly than larger pieces. This especially helpful with tough vegetables such as broccoli stalks, cauliflower, cabbage leaves, and root vegetables. One exception to this is when you plan on being out of town for vacation. This is when we put tough vegetable matter in the bin. Sometimes it can take weeks for tough matter to break down; this gives the worms a long term food source.

Another method of breaking down material is to put the fruit and vegetable scraps in plastic storage bags and placing them in the freezer for a few days. When thawed out this material quickly becomes mushy and breaks down rapidly. Freezing also kills off seeds and little critter eggs that may be along for the ride.

For the really dedicated there is thawing frozen worm food in the micro-wave, I will admit that we have done this more than once during the winter when we keep a 5 gallon bucket on the porch filled with vegetables. Again this aids in the break down process of vegetative matter.

For the worm farmer raising worms in large bins indoors or outdoors which they will sell to vermicomposters or for bait the same food sources used by the home vermicomposter are fine. However for consistency sake, not to mention a steady food source, these types of operations will often use commercially produced worm food, such as Purina Worm Chow. Or they will mix up their own blend of prepared worm food to reach a well-balanced diet of nitrogen and carbon.

For worm farmers wanting to produce large size worms or are focusing on castings getting worms should be fed a consistent diet of highly nutritious food.

Manure for Worm Food

Arguably the absolute best food source for worms is animal manure. Both home vermicomposters and commercial worm farmers use animal manure as their primary food source with great success. Manure is nutrient rich and composting worms thrive in it. In fact when you visit a farm you would likely find plenty of red worms in the nearest mound of aging horse manure.

While manure makes a great food source for composting worms don’t rush out and grab the first pile of animal poo you see and feed it to your worms. Some types of manure are much better for your worms than others.

Composting worms do best in aged manure; in fact fresh manure is so rich in nitrogen that dumping it straight into your bins would likely have some negative effects on your worms. Even aged manure should be mixed with other materials such as peat moss or shredded paper. You should also consider where you are getting your manure from. A small horse ranch that immediately moves manure to piles will likely provide some good clean manure. While a large industrial farm where manure comes into contact with urine, other feed sources, and even chemicals may have manure that can be downright dangerous to worms.

The most common type of manure in used by worm farmers is aged horse manure. Hog manure and cattle manure are also a popular choice; however with these manures the solids should be separated out. Some worm farms do report good success with rabbit manure and even some more exotic manure like llama manure. Others use chicken manure from their chicken coops. However be very cautious when using bird droppings; which again are very high in nitrogen. We strongly suggest mixing some carbon to bird droppings to offset the nitrogen.

No matter what manure you choose to feed your worms we strongly recommend you let it age before you use it as a bedding or food source. Some worm farmers call this pre-composting and it allows the organic matter to start to decompose for a while before it’s added to worm bins.

Another problem with fresh manure, or any composting material, is that it goes through an initial hot composting stage. In other words the composting process generates heat. Large quantities of fresh composting materials can actually heat up a worm bin enough where worms will try to escape or worse die.

We find that pre-composting for a about a week works well for manure. We also pre-compost many other foods we intend on using for worm food. One exception is material we add to our compost tumbler where it is allowed to compost for weeks, or months on end. This composted material is a key part of our preferred bedding mixture.

How much to feed worms

Compost worms have a hearty appetite, theoretically able to eat more than their body weight each day. However that consumption potential is under ideal conditions and the average worm farmer should not expect their worms eat quite that much.

We find that a more reasonable expectation is about ½ their body weight each day. Now mind you; we don’t weigh each worm then calculate how much to feed them. Instead we estimate how many worms, by pound, are in various bins. Then we place twice that weight in food in the bin a couple times a week. After that it’s a matter of monitoring how much the worms eat and adjust food amounts based on consumption. This is a basic guideline that works for us.

For the beginning worm farmer it’s really pretty easy to figure out how much to feed your worms. Say you start out with about 2000 worms. If you bought them from a reputable source they should weigh about 2 pounds. At a consumption rate of ½ pound per day that would mean your worm farm should be able to process around 6 pounds of food per week. Again; this is only a rough estimate.

It’s important to remember there are many variables in determining how much to feed your worms. Some of those variables include; type of food, how long it was pre-composted, temperature, bedding, and moisture levels. For us the biggest variables are temperature and bedding. During the winter we have lots of indoor bins in the basement; and it gets pretty cool down there. At this time food consumption goes down to only about ¼ of summer time consumption.

Bedding will also be a large variable. We use our own mixture of bedding made up of leaves, shredded cardboard, and coffee grounds, plus a few other things. Each and every one of these items are a good food source in their own right, so it would only stand to reason that our worms eat a bit less of the food we give them than expected.

As mentioned above simply how you prepare your worm food will have a big impact on how quickly your worms can eat a given amount of food. Cabbage leaves are a great illustration of this. If I simply place a few fresh cabbage leaves in a bin they will literally last for weeks. Take the same cabbage leaves; chop them up, freeze then thaw them, run them through the food processor with other food, then place them in the worm bin. They are gone in a matter of days.

Worm Food Distribution

Food distribution will be dependent on what type of bin you have for your worms. Remember, you should have a plan for food distribution, especially when introducing any new types of food.

Instead of just tossing all your food into your bins develop a feeding plan. For enclosed wooden or plastic bins we like to divide up our allotted food into smaller amounts then distribute the smaller piles in the corners, or on one side of the bin. In the event your food source aggravates your worms they will have a safe area of the bin to move to. Similarly if you add a food substance that starts to hot compost the entire bin will not get too hot and your bins will have cool areas for your worms to hang out in.

Final thoughts on Worm Food

While it is important to monitor and track worm food consumption the casual worm farmer should not overly worry about it. Start with the recommended guidelines and go from there. See how quickly, or slowly your worms eat what you provide them and adjust as needed. Remember that temperature and bedding material will have an impact on worm food consumption. Above all don’t over react if food consumption varies from time to time. Stick with our recommended foods and don’t over feed your worms and you should do just fine.

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