There are few friends in the garden more important than the earthworm. Worms increase the permeability of soil, improving drainage and allowing more air and water to penetrate the soil. They eat organic material and the waste they produce, referred to as worm castings, is a micronutrient-rich organic fertilizer. Worm castings are not only rich in the micronutrients our plants crave, but they are full of beneficial bacteria.

Now, what if I told you that you could bring the benefits of worms to the indoor garden? What if you could use them to make your own fertilizer loaded with micronutrients and you could do it essentially for free? Too good to be true? Actually making, maintaining and harvesting your own vermicompost is a really simple process that anyone can learn if they follow a few easy steps.

Making Your Own Worm Bin

Worm bins are easy to make at home. First, you need a box or bin (plastic storage containers are great for this) to house your worms and the compost. The size of the box depends on the amount of food scraps your family produces; however, the box must be no taller than 12 to 18 in. otherwise the weight of the compost can cause compaction—and if there is not enough air getting to the compost, it won’t be a healthy environment for the worms and millions of beneficial bacteria that are converting the compost into a great organic fertilizer. To further improve oxygen levels in your worm bin, drill small holes around the sides of your container, roughly 2 to 4 in. above the base.

The next step is to line the base of your worm bin with a couple inches of bedding. Bedding will house the worms and can be made from a light organic material—shredded newspaper that has been moistened but not soaked with water makes great worm bin bedding.

Once the bedding is in place you can add the worms. Worms can be purchased at bait shops or dug up in a garden. The worms will work their way down into the bedding instinctively.

Feeding Your Worms

Now that your worms are comfortably set up in your worm bin, it is time to start feeding them. Spread organics loosely over the bedding. Most table scraps are acceptable to add to your worms bin. Fruit and vegetable rinds are great, as well as eggshells and coffee grinds (in small amounts). You can also add lawn clippings, leaves and used napkins and paper towel. Try to avoid adding meat, dairy and fatty foods, mainly due to the odor (especially if your worm bin is indoors). Also, citrus fruits can be a problem if you add too much.

Harvesting Your Vermicompost

After 2-3 months, your vermicompost is ready to be added to your indoor or outdoor garden. If you are able to wait four to six months, the organics in your worm bin will resemble healthy soil. To harvest your vermicompost, you need to sort out the worms. One of the easiest ways to do this is to spread the contents of your worm bin on a tarp underneath a light. Try to pile it all into a pyramid shape. The worms will instinctively move away from the light, to the lowest section of the vermicompost pyramid. Remove the top third of the pile and repeat the process until you have removed most of the compost and most of the worms are left in the bottom. Keep the last bit of compost containing the worms and reintroduce it into your worm bin once you have adding fresh bedding. The little bit of compost will accelerate the break down of the next round of organics added to your worm bin. You can now repeat the process of feeding and harvesting year round.