How to Feed Composting Worms

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Welcome to the second post in this series about how to build and take care of a simple worm farm. Be sure to check out the first post if you haven’t already. You’ll find all the details about how to build a warm farm using plastic storage containers. This is the perfect beginner worm farm for you or your kids. Now, let’s dive into what and how to feed your composting worms. 

 

 

What to Feed Composting Worms

Red wiggler worms feed on the microbes that feed on decomposing matter. Since worms don’t have teeth, they’re not really munching on the food itself. That being said, we still talk about what food the worms like to eat. There are two parts to their diet…nitrogen and carbon materials. The carbon materials make up the bedding, but it is also a food source for them. The nitrogen materials come from your kitchen.

 

Carbon (Bedding)

• shredded black and white newspaper, paper grocery bags, cardboard
• torn paper egg cartons
• dry crumbled leaves
• torn up paper towel and toilet paper rolls
• printer paper is okay as a last resort (but try to avoid it)
• NO glossy paper

 

Nitrogen (Food)

• fruit and veggie scraps (use more vegetables than fruit)
• used coffee grounds and unbleached filters – occasional use only
• Broccoli and other cruciferous vegetables give off strong odors when decomposing. Avoid if worm farm is kept indoors.
• NO oils, butter, fats, or dairy
• NO animal based items (bones, meat, fat, eggs)
• eggshells are ok (more about them below)
• NO citrus, onions or garlic (can be used in small amounts in larger farms by experienced worm farmers)
• NO human or pet waste, hair or fur

 

Prepare the Food

Smaller pieces of food will decompose more quickly. You can certainly put a whole cucumber in there, but it will sit for a bit before the worms get to it. Cut up the pieces into about 1″ chunks…no need to dice it finely. You can keep the food scraps in a compost crock until you’re ready to feed them.

You can also place the food scraps in the freezer and thaw before feeding the worms. Freezing kills any bug eggs and also kick starts the decomposition process. I like to thaw the food in a bowl of bedding material (shredded black and white newspaper, torn paper egg cartons, shredded paper bags). Use about equal parts food and bedding by volume.

Whatever you do, PLEASE do not blend the scraps! Blended food can “disappear” easily into the bin which makes it hard to see. Many new worm farmers who try this end up killing their worms by overfeeding them. There’s just no need to blend and it’s very risky.

 

How Much to Feed Your Composting Worms

Red wiggler worms can eat half of their body weight every day…BUT this is NOT where you want to start. This is a common worm farming fact that gets tossed around without the explanation that new worm farmers need. This is under ideal laboratory conditions which is difficult, if not impossible, for home worm farmers to create. Although, it does make for some fun measuring activities for kids!

Start out with one handful of food and place it in a corner buried under the bedding. When this is almost gone, add another small handful to another corner. When that’s almost gone, add another small handful to another corner. Keep repeating this.  You’ll soon get a feel for how much to feed and how often.

Kids can measure and weigh the food and keep track of the feedings on a calendar. They may even find certain foods that their worms just love!

 

Add a Buffer

Buffers help prevent the worm farm from becoming too acidic. Decomposing food creates acidic conditions but worms can die if it is too acidic. You can use azomite, dolomite lime, zeolite, garden lime or finely ground eggshells. Bake the eggshells at 200 degrees for 20 minutes or until completely dry. I’ve also used the rock dust blend that comes with the Worm Factory kits. Sprinkle a light dusting of one of these over the food each time you feed the worms. I use eggshells with each feeding and then add a sprinkle of some rock dust over the whole farm once a month. Very lightly mix it into the top inch. Use a face mask to prevent breathing in the dust.

 

Add More Bedding

Too much nitrogen based food can lead to anaerobic conditions in your bin which can kill your worms. It’s important to err of the side of too much bedding to avoid this. I add an equal amount of bedding material, by volume, mixed into every feeding. When I feed, I leave a small layer of bedding below the food and cover it up with additional bedding. Having a thick layer of bedding on top of the food helps prevent pests from getting into the bin.

 

How Much Moisture?

Most people do not need to add additional water to their worm farms. The water that is released as the food decomposes is usually enough. A worm farm should be damp like a wrung out sponge. If you live in a dry climate, you may need to add additional water. Just sprinkle it on top. Don’t drench it. Worms do not swim! Too much moisture can lead to anaerobic conditions which can kill your worms.

 

What About Leachate?

Leachate is the liquid that can sometimes drain out of the bottom of the bin. Some leachate is okay but any more than the occasional little bit is a sign that your bin is too wet. Leachate is NOT worm pee. Yes, many new worm farmers believe that, but it’s simply not true. It is the result of too much moisture. Leachate can have harmful microbes in it (due to an anaerobic environment), so it’s best to toss it down the drain instead of using it in your garden. If you’re regularly getting leachate, mix in dry bedding material to soak up the excess moisture. Corrugated cardboard is great for this.

 

Now that you have your worm farm built and running, be sure to check out the next post in this series all about harvesting your worm castings! (It’s my kids’ favorite part!) Learn how to harvest it and use it in your garden.

 

Other Posts in the Series

Post #1 – How to Build a Worm Farm

Post #3 – How to Harvest Worm Compost