Worms at Work: Vermicomposting 101

Compost is Key

We all know compost is good for your garden soil, and that I’m a big fan of incorporating composting into the garden cycle- but did you know that worm castings are nature’s effortless and ideal answer to up-cycling!? Vermicomposting is the practice of using worms to decompose food scraps and using their worm poop (aka worm castings) to grow more great  food. 

Melanie with some impressive garlic- must be the worm castings!

I asked local vermicomposting expert, Melanie Harding, to help us understand more about using worms to transform trash into treasure. Melanie has been Tamarack Nature Center’s Naturalist Coordinator for going on 5 years. She’s most happy when she gets to help people have those light bulb moments when they make a nature connection. Her info here will have light bulbs going off all over the place!

So… let’s all learn a little more from Melanie:

I have a deep respect for decomposers – those marvelous creatures that recycle nature’s leftovers into the building blocks of new life. That probably doesn’t surprise people who know me, as I have been working in the field of environmental education for more than 25 years. But when someone finds out I have worms living in my kitchen, the reaction is usually surprise…followed by disgust…and eventually curiosity. Those who are curious enough to ask about the three bins stacked inconspicuously in the corner, open a proverbial “can of worms” at my house. I have worms living in my kitchen and I love to talk about them!

Everyone can help with the worms!

I first learned about vermicomposting (composting with worms) in the 1980’s through a series of publications and education initiatives called “Worms Eat My Garbage,” by Mary Appelhof. Mary, affectionately known as the “Worm Woman,” is no longer living, but her worm composting legacy continues in the form of updated publications and a website (http://www.wormwoman.com.) It wasn’t until about 10 years ago that I started vermicomposting in my own home. I find it wholly satisfying and a super easy way to give back some of the resources I’m taking from the Earth to sustain myself. My family supports me in this obsession. I hope yours will too!

Some “Worms of Wisdom” About Vermicomposting…

 What is vermicompost?

Worm Heaven. Photo Credit: Melanie Harding

There’s no getting around the fact that vermicompost is worm poop. But this is the best smelling excrement you’ll ever encounter! It’s dark and rich and smells like the goodness of the Earth. It’s extremely high in soil nutrients like nitrogen, phosphorous and potassium – all the things you find in a commercial fertilizer. You can boost the quality of your garden and the health of your plants by continuously incorporating vermicompost into your soils.

What kind of container do I need?

You can use any durable container as long as it doesn’t degrade over time and interact with the environment or release contaminants. I use plastic because it’s inexpensive, easy to work with, light-weight and stackable. My go-to worm composting container is the classic 10-gallon Rubbermaid tub. I’ve been using the same 3 tubs for the last 10 years. You can also purchase ready-made worm composting containers online. 

Lots of composting going on inside neatly stacked bins. Photo Credit: Melanie harding

Where should I put my worm bin?

Vermicomposting can happen indoors or outdoors as long as temperatures remain between 55 and 77 degrees Fahrenheit most of the time and the bins are protected from heavy rain and direct sunlight. I keep my worm bins indoors because I don’t want the trouble of moving them in and out with the seasons. As indoor bins, they are also more convenient, cleaner and well-maintained. While I keep mine close-by, in the kitchen, I know composters who set up their systems in a basement, on a porch or in a heated garage. 

What kind of worms do I need and where do I get them?

The Red Wiggler

One of the best vermicomposting worms is the red wiggler (Eisenia foetida). This is not the kind of worm you can dig up in the yard. It can be purchased at bait shops and pet stores, or you can order them online for about $35 per pound (about 1000 worms). The red wiggler is a good container composting worm because it’s a surface dweller and does not need to burrow very deep to be happy. The red wiggler can consume half its weight in food each day. I would recommend starting a new bin with about ½ pound of worms. They will reproduce quite quickly if they have what they need to thrive. Each square foot of space in the bin can accommodate about 1000 worms. When my 10-gallon tubs are going strong, they can support about 2000 worms each! 

Why are there other critters in my worm bin?

A worm bin is a micro-ecosystem that contains a variety of living organisms. Bacteria grow in a worm bin and play a vital role in the health of the system. Other decomposers may also be present, so don’t be surprised to find millipedes, sow bugs, springtails and even small snails in your worm bin. Fruit flies are also decomposers, but they are less desirable in a vermicomposting system, especially an indoor one!

What should my bin look like?

Open Bin Photo Credit: Melanie Harding

A healthy worm bin is very low-maintenance, but it does need 5 things to remain healthy: (1) darkness (avoid clear containers that let in light), (2) water (bin contents should be moist but not soaking), (3) bedding, (4) air flow and (5) food. If these elements are out of balance, your bin can produce unwanted odors, attract unwanted pests or even die.

What is bedding and why do I need it?

You’ll need some organic “bedding” for your worm bin to keep in the moisture, maintain the temperature and to cover the food scraps. Bedding can be as simple as shredded newspaper or cardboard. Most inks in newspaper are soy-based now, so they are safe for your worms, even the colored inks. (Avoid the shiny ads and extra inserts that come with newspapers.) You can also use straw or dry leaves for your bedding, especially if it is an outdoor bin. I use newspaper because I keep my bins indoors and don’t want to bring in unwanted visitors with the outdoor materials. The worms will eat the bedding over time, so you’ll need to add more as it gets recycled. The bedding should be moist but not too wet – like a fully wrung-out sponge.

What can I feed the worms?

Food scraps ready for feeding. Photo Credit Melanie Harding

Any organic materials can be composted. However, for an indoor compost system, I recommend sticking to fruit and vegetable scraps, coffee grounds (and tea) and crushed egg shells. Adding anything meaty, oily or dairy-based could bring unwanted odors and pests into your home. Cut or tear food scraps into smaller pieces for quicker composting. I keep food scraps in a container in the freezer so they don’t sit around too long and make a mess. At feeding time, I just pull a container out of the freezer and let it thaw in the sink. ALWAYs cover your food scraps with bedding. My best advice to new worm composters is “don’t dump and run!”

How much should I feed my worms?

Red wigglers can eat about half their weight in food each day. That means 1 pound of worms can eat 3 ½ pounds of food each week! As someone who wants to avoid the potential problems of overfeeding, I do not give my worms that much food. I provide each 10-gallon bin with 1-2 pounds of food per week, depending on what my family has eaten (or not eaten) that week. A pound of food is about 4 cups. I use 4-cup plastic containers in my freezer to hold the food scraps until I’m ready. It doesn’t have to be exact – approximations are just fine!

I rarely open my bins more than once a week. While feeding each week, I check moisture levels. If the bins are too dry, I add some water. And if they are too wet, I add some additional bedding or set them outside to dry out for a while. If they need more bedding, I start shredding newspaper. Overall, I spend about 15 minutes each week maintaining my worm bins.

How do I harvest the compost?

Pick those worms!

As your worm bin fills up with valuable vermicompost, you’ll need to decide on a way to harvest the compost so you can put it in the garden. There are a variety of methods for harvesting. My favorite is to simply dump the entire contents of a bin out onto a tarp and start separating worms from compost. It’s relaxing and you learn a lot about your worm bins through this process. If you have kids around, enlist their help and make them into official “worm pickers.” I have kept kids busy for hours with this activity! You can also use a migration method for harvesting. If you feed the worms in the same place each week for about a month, they will all migrate to that area in the bin, making it easier to separate them from the compost.

How do I get started?

First decide on a container. You can make one or buy one. I would recommend starting with at least ½ pound of worms (about 500 worms), which you can purchase. (Vermicomposters usually love to share worms if you can find someone who already has healthy bins going.) Add plenty of moist bedding at the start. Inoculate your bin by adding a handful of finished compost or some garden soil. This will get the bacteria and other critters going in your bin. Add about a ½ cup of sand. The worms use this grit in their digestive system. Once your bin is ready, let the worms acclimate for a few days before starting to add food.

For more information, including instructions for building your own worm bin, troubleshooting your system, feeding tips and harvesting methods, Oregon State University Extension has a great online resource HERE.

Layers in the bin. Photo Credit: Melanie Harding

Thanks Melanie!!

Using Worm Casting in the Garden

Basically, worm castings are Garden Gold. They are actually better for most plants than regular compost- because of the exact neutral 7pH of castings, and the HIGH level of available micronutrients that slow release.  The benefits of worm castings have been long understood but are gaining even more traction now as we’re understanding our personal roles in reducing the amount of food waste, and increasing our home gardens. For a deeper dive into benefits  of worm castings check out this article. If you want to start with a regular compost pile first, read my Dot Com Post all about why I love composting. Or if you’d prefer a video, our guest blogger Melanie if featured in THIS VIDEO answering your composting questions. 

So, obviously I’m experimenting with worm castings  in my gardens this summer, side by side comparisons coming soon! And we plan to start our own worm farm this winter to make our own potting soil mix for next year’s seedlings.  It does help that my kids LOVE worms! If yours need some more coaxing, the book Yucky Worms should move them (or you) in the right direction!

So, everybody; go hug a worm today!

Dig In- but carefully so as not to hurt all those worms at work!

Michelle