Vermicomposting

Using this simple technique, you can turn your kitchen waste into nutrient-rich compost that will have your garden looking beautiful, green, and healthy.

By Susan Wanjiru

Vermicomposting (worm-composting), is the process of using worms to turn organic waste, such as kitchen waste, into nutrient-rich compost. The worms eat the waste and excrete nutrient-rich excrement known as worm castings – a rich, dark, crumbly form of compost loaded with nutrients.

This method of producing compost is encouraged because it is a sustainable, low-cost, and environmentally friendly way to turn household and agricultural waste into high-quality compost.

Vermicomposting is usually done in a smaller scale than your regular compost pit. Therefore, you will not be able to put in debris from your farm such as dried leaves, twigs, etc. Feed your worms with waste like potato peels, cabbage, and carrot peels, amongst others. Avoid giving them oily foods or one kind of food. They will do better when you provide a variety of foods. Also, avoid giving too many citrus foods as they are very acidic and can kill your worms.

Benefits of Vermicomposting:

1. Worm castings (black gold) contain higher amounts of nitrogen, phosphorus, and potassium than traditional compost.
2. It reduces the amount of organic waste that goes into garbage sites, thus  reducing the production of methane- a potent greenhouse gas.
3. If done correctly, a vermicomposting system produces minimal odour and does not attract pests.
4. Worms can consume waste equivalent to their body weight every day. Thus, a well-maintained worm bin can produce compost faster compared to some of the usual traditional methods.
5. Vermicompostingis usually done indoors and outdoors, making it an ideal composting option for urban and rural settings.

How to Start Vermicomposting:

1. Selecting a Bin: Look for a plastic container, purchase a worm bin, or make a wooden or plastic box. When deciding on the size of your container, consider the amount of waste you generate from your kitchen. If you get about 1/4 kg-1/2 a kg of waste daily, the  bin should measure 2ft wide x 3ft length x 1ft deep. Put about 0.5 -1 kg of worms in it.
2. Put holes for aeration and drainage at the bottom of your bin and on the side around the perimeter about an inch from the top.
3. Bedding: layer the bottom of the bin with shredded newspaper, cardboard, or coconut coir as bedding. Ensure your beddings are moist but not soggy.
4. Worms: Purchase the worms from a reputable supplier and put them into the bin. Though some people have used the regular earthworm to populate their bins, the best worms are the small red worms known as red worms, or red wrigglers.
5. Feed the Worms: Add small amounts of organic waste (fruit and vegetable scraps). Avoid meat, waste from dairy products, and oily foods. Gradually increase the quantity of food as the worm population grows.
6. Maintenance: Keep the bin in a dark and cool place. Maintain moisture levels and turn the bedding occasionally to provide aeration.
7. Harvesting: In a few months, the bin will be full of worm castings. You can then harvest the compost and start the process again. Worms increase in number fast . When fed correctly, their numbers will double every month.

Challenges:

1. Overfeeding: This can lead to odor and pest issues. Feed your worms according to their consumption rate.
2. Temperature and moisture extremes: Worms are sensitive to temperature and moisture. Keep the bin where temperatures remain between 13°C – 25°C. Adjust moisture by adding dry bedding or sprinkling water as needed.
3. Predators and Pests: Occasionally, bins might attract pests or predators like fruit flies and ants. Addressing overfeeding and maintaining the correct moisture levels can help reduce these problems.

Points to note:

• Ideally, harvest your worm castings every 3 to 6 months. To do this, place fresh food on only one side of the bin. Your worms will migrate towards the food. Worms will migrate when the food gets finished on the side without food. Following their migration, gently scoop out your worm castings from the side they have migrated from.
• To use, place your worm castings on the top of your potted plants and let the nutrients seep down as you water them, or mix them with topsoil when preparing your planting soil.
• Worm castings are rich in nutrients, or that reason, use them as you would utilise a highly nutritous fertiliser. Avoid using too many worm castings. If, for example, your soil is already nutrient-rich, do not add more.

In conclusion, vermicomposting is an environmentally friendly way to handle your organic waste. It’s also a means to produce high-quality compost beneficial to gardens and plants. By understanding the basics and maintaining the right conditions, anyone can turn their waste into a valuable resource for your shamba.