Are you a seasoned gardener looking for your next challenge or perhaps a budding zero-waste enthusiast ready to leap into action? Using worms may be a great choice if you are looking to accelerate the composting process or are short on outside space – and your plants will thank you!
Worm composting, known officially as vermicomposting, is an indoor method using red wiggler worms to break down kitchen food scraps, producing rich compost in a matter of weeks. Just as outdoor composting, worm composting protects the climate by keeping food scraps out of landfills. The US Environmental Protection Agency estimates that 24% of the volume of landfills is wasted food. When used in landscape beds or added to potted plants, worm castings increase soil fertility and, thus, the health of your plants. Composting with worms is inexpensive, easy, space-saving and turns food waste into black gold.
Getting Started
Check out this comprehensive guide from NC State Extension Specialist Rhonda Sherman. Starting a worm composting system is a simple process:
- Purchase a bin to house the worms or make your own
- Identify a good place in your home for storing the bin like a closet or under the sink
- Purchase a supply of red wiggler worms (Eisenia fetida)
- Moisten shredded paper, cardboard or coconut coir (bedding) and add to the worm bin
- Add kitchen scraps and cover with more bedding
- Add the worms
- Check on the bin every day or two, misting with water if dry and adding more adding bedding as needed or if too moist.
- Feed worms more scraps weekly – under ideal conditions worms can eat their weight in scraps per week (1 lb. of worms can consume up to 1 lb. of scraps)
- Harvest the worm castings
- Top dress indoor or outdoor plants with castings to increase nutrients and beneficial microorganisms
It’s important to identify a good location for the worm bin – the optimal temperature range for red wigglers is between 60- and 77-degrees Fahrenheit. In our southeast Texas climate, worms must be kept indoors, as they will die if it is over 95 degrees Fahrenheit. Common locations where the worms will be undisturbed but not forgotten include under the sink or inside a closet. The garage is much too hot for red wigglers to survive. Ensure that your bin is opaque with a secure lid to keep out light and contain the worms.
Tips for Success
Maintaining the worm bin requires creating a routine. Add food scraps and check the bin moisture once a week. Be sure to only add foods from the “do” list and cover with bedding to deter fruit flies. Each time the worms are fed, place the food in a different location in the bin. This entices the worms to move around in the bin, leaving their castings in an even layer on the bottom. Over time the worms will consume some of the bedding; simply add more bedding and moisten it with the spray bottle. Additional bedding may need to be added about once per month.
Troubleshooting Common Problems
| Problem | Cause(s) | Solution(s) |
| Foul odor | Overfeeding | Reduce amount fed; stop feeding for a few days |
| Not enough air | Use small gardening tool to fluff up bedding | |
| Too wet | Add dry bedding | |
| Worms dying | Bin too moist | Drain excess water; add dry bedding |
| Bin too cool or too warm | Check internal bin temperature | |
| Not enough food | Add extra food | |
| Too dry | Not enough moisture | Spray gently with distilled water until bedding is moistened |
| Fruit flies | Too much food in bin | Add more bedding; place fruit fly traps around bin; keep kitchen scraps refrigerated to prevent infestation with fruit flies |
Harvesting & Using Vermicompost
When a few inches of worm castings have accumulated in the bottom of the bin, it is time to harvest the castings. Follow these steps to harvest castings:
- Remove the top 1/3 of the bin (bedding, food scraps and worms)
- Scoop out the bottom layer and place in a separate container for use on plants
- Return the top 1/3 containing bedding, food scraps and worms
- Add fresh bedding and gently mix well
For a full guide on the three methods of harvesting vermicompost, visit this guide.
Worm castings are a rich addition to soil, whether in potted plants or in the garden.
- Soil amendment—blend three parts potting soil to one part worm castings
- Fertilizer—topdress houseplants and outdoor container plants with a shallow layer of worm castings
- Transplanting—add a scoop of worm castings to the bottom of the planting hole, then add the plant and cover with potting soil or garden soil
Worm Composting Resources
Unfortunately, there are no local worm farms in the Montgomery County area. Research online retailers, making certain that the retailer sells red wigglers worms (Eisenia fetida) by the pound. One pound of red wigglers equals approximately 1,000 worms and a good ratio to start is one pound of worms per square foot of surface area.
For more information, watch the video or visit the guide below:
I have been using compost tumblers for a couple years, filling them with correct kitchen scraps. I haven’t added much brown material, leaves and cardboard. Now my tumblers are full and dry. How can I stimulate the material to decompose?
Hi Laura,
Great question! Creating compost requires green material (kitchen scraps, grass clippings, green plant trimmings, coffee grounds); brown material (dry leaves, brown pine needles, frozen plant material); water (rain); and air. The brown and green material must be present in proper ratios (2 parts carbon—brown—to 1 part nitrogen–green). Air is required to provide oxygen to the decaying plant material. (A tumbler system usually does not have free access to the open air, so may lack sufficient oxygen). In addition, the decomposers that are naturally present in the soil are not available to material contained in a tumbler system. Soil decomposers include bacteria, fungi, nematodes, arthropods, and protozoa. These organisms move directly from the soil into an open compost pile. They do the work of decomposing the organic material. Since the tumbler system is full, you would need to remove at least 2/3 of the material and replace it with natural brown material (dead leaves, pine needles, other dead plant material). A small amount of water would need to be added. Adding the proper amount of water is challenging since most tumblers do not drain. If too much water is added, the plant material may become anaerobic, which creates fermentation rather than decomposition. If you would like anymore guidance, please feel free to email at enviro@thewoodlandstownship-tx.gov or call us at 281-210-3800 and ask to speak to Environmental Services.