Composting worms will produce nutrient-rich fertilizer for your garden, but you need to feed them right. This is not difficult. Treat these invertebrates like little living creatures – which they are! Worms have likes and dislikes. Putting the right mix of food into your vermicomposting bin helps them do their job: turn trash into treasure.
Let’s start with what composting worms dislike. They don’t like an acidic environment. Whatever you add to the worm bin becomes part of their environment. So, do not add acidic foods such as:
- Citrus fruit (oranges, lemons, limes and their peels)
- Pineapple flesh and rind
- Large quantities of raw onions
Worm bins should smell faintly of earth. Therefore, meat and oils must not be given to worms. The problem with meat and oils is that they go rancid. This stinks up the bin. It also attracts pests such as raccoons. So avoid:
- Meat of all types
- Dairy products such as milk, cheese, yogurt and cream-based sauces
- Large gobs of salad dressing (rinse it off)
- Oily foods like deep-fried French fries and eggplant Parmesan
- Processed foods that are high in salt and additives
- Banana peels -unless buried -if you are composting indoors due to bad odors and fruit flies (outdoors is fine)
What do worms like? If you avoid the items listed above, these worms are not finicky eaters! They love these items straight out of your kitchen and garden:
- Vegetable peelings
- Left-over, extra and spoilt vegetables
- Fruit peelings and fruit flesh
- Fruit cores (if the seeds sprout, pull them)
- Grains, such as oatmeal, rice, bread and potatoes without heavy sauces or butter
- Coffee grounds and used tea bags
- Small amounts of pesticide-free grass clippings (too much will heat up the bin)
Be sure to cut up the food into small pieces. Pieces should be no larger than 1″ to 2″ at the widest dimension. A food processor or food chopper are handy. These smaller pieces have more surface area and are easier for the worms to eat.
Bury the food. This prevents odors, makes the material easy for the worms to find, and discourages pests. Worms also like it if you start feeding in one spot and, at the next feeding, bury the food in a spot next to it. Gradually work your way around the bin. This makes the migration to the new food faster.
You should feed the worms a quantity they can eat in approximately 2 to 3 days. Wait until they have made good progress on a feeding before adding more. If you are producing more than they can eat, put the extras in the freezer or refrigerator. Eventually, they may reproduce and be able to handle larger and more frequent feedings. A tray-based composting system is perfect for this, because you can add trays as the population expands (kind of like an apartment building that keeps adding floors).
Maybe you have heard about having a mix of “green” and “brown” material for composting. If you are not using worms to break down the compost, this ratio is very important. It helps speed up the rate of composting, and prevents foul odors. The mix is 1 part “green,” fresh, moist plant-based scraps to 3 parts “brown,” dry materials. When you set up your worm bin, you added plenty of brown materials as the worm bedding (shredded paper, coconut coir, pure peat moss, etc.). Whenever you add kitchen scraps, you are adding “green.” Therefore, so long as you don’t over-feed your worms, you don’t need to worry much about this ratio.
Every once in a while, you can throw in a handful of egg shells. Rinse them and remove any egg whites stuck to the shell. Then, crush them and stir them into the worm bin. They add grit and calcium, and help moderate the bin’s pH.
The care and feeding of vermicomposting worms is not rocket science, but it takes a little discipline. Collect suitable scraps in a container on your kitchen counter or in the refrigerator. Pick out any meat, oils and banana peels. Bury the food in the vermicomposting bin at a pace that matches your worms’ appetite. The result will be less waste and plenty of precious “black gold” to fertilize your plants.