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Worm farm, bin or bath

Photo by Sippakorn Yamkasikorn: https://www.pexels.com/photo/earthworms-on-a-persons-hand-3696170/

A worm farm is a simple way to keep compost worms and harvest their vermicompost and worm tea for use as fertiliser or insect spray.

You can keep compost worms in a simple bin, in a clever three tray worm farm or in an old bathtub called a worm bath. Here we explain all three methods so you can choose which one works best for you.

Worm bin


Creating a Simple Worm Bin:

  1. Choose a location: Your worm bin has holes at the bottom so it needs to be able to drain. A spot on some gravel could work.
  2. Select a Container: Begin by choosing a sufficiently large plastic container, similar to what you might use for storage. Ensure it comes with a lid.
  3. Provide Ventilation: Drill or punch holes into the lid and the bottom of the container. This is important for allowing proper airflow and drainage.
  4. Prepare Bedding: Line the container with torn-up pieces of newspaper or cardboard. Think of it as creating a cozy bed for the worms. Slightly moisten the bedding, striking a balance between too dry and overly wet conditions.
  5. Introduce the Worms: Acquire worms, often available at gardening stores, or obtain them from someone who maintains a worm bin. Ask on the NOA Whatsapp group. Gently place the worms onto the prepared bedding. These worms serve as efficient decomposers.
  6. Add Food: Begin by placing small, manageable amounts of food scraps such as vegetable peels, coffee grounds or tea bags into the bin. Position the scraps beneath the bedding, making it accessible to the worms.
  7. Cover and Wait: Seal the container with its lid. Worms prefer darkness, so this step is important. Allow the worms to go about their work, converting the food into nutrient-rich material that benefits plant growth.

Caring for the Worm Bin:

  1. Maintain Moisture: Monitor the moisture level of the bedding. If it feels excessively dry, lightly sprinkle water to create an environment that’s comfortably damp. Remember, worms thrive in a damp habitat.
  2. Feed in Moderation: Every few days, offer small portions of food to the worms. It’s essential not to overdo it to prevent unpleasant odors. A balanced approach ensures a healthy bin. Learn here how to care for the worms.
  3. Environmental Conditions: Keep the worm bin away from direct sunlight and rain. Worms are sensitive to both extremes. Find a shaded spot that safeguards them from harsh weather elements. Indoors is best.
  4. Harvest Compost: After several weeks, the worms will transform the organic matter into valuable compost, packed with nutrients. Carefully separate this dark, rich material from any remaining food scraps. It’s an excellent resource for nurturing plants.
  5. Utilize Worm Tea: Occasionally, liquid may collect at the bottom of the container. This “worm tea” is a concentrated liquid fertilizer. Employ it by diluting it with water and using it to nourish your plants. The three tray worm farm described below is a better design to manage the worm tea.
  6. Appreciate the Process: Observe the worms as they work silently to break down organic matter. Their role as nature’s decomposers and garden enhancers is fascinating to witness.

In essence, maintaining a worm bin is akin to tending to a small ecosystem that contributes to ecological sustainability. By providing a conducive habitat and periodic attention, you facilitate the remarkable process of organic waste conversion into nourishing compost.

Three tray worm farm


Building your own three-tray worm farm from plastic trays is a DIY project that can be both cost-effective and environmentally friendly. Here’s a step-by-step guide on how to build a DIY three-tray worm farm using plastic trays that you can purchase from a store:

Materials You’ll Need:

  1. Three plastic storage trays (shallow and stackable)
  2. Lid for the top tray (can be made from plastic or other suitable material)
  3. A collection tray or container with a tap (for collecting worm tea)
  4. Drill with various-sized bits
  5. Fine mesh or screening material
  6. Organic bedding materials (shredded newspaper, cardboard, coconut coir)
  7. Red wiggler worms (Eisenia fetida)
  8. Organic kitchen scraps

Step-by-Step Guide:

  1. Choose a Location: Pick a suitable location for your DIY worm farm. Like the store-bought version, this location should be shaded and protected from direct sunlight and extreme temperatures.
  2. Prepare the Trays: Drill holes in the bottom of each plastic tray for drainage and aeration. Use different-sized drill bits to create holes of varying sizes. These holes will allow excess moisture to drain and air to circulate through the trays.
  3. Prepare the Lid: If your top tray doesn’t already come with a lid, create a lid using a plastic or sturdy material that fits over the top tray. This will help keep the system dark and discourage pests.
  4. Create a Collection Tray with Tap: Find a plastic container or tray for collecting worm tea (liquid runoff). Attach a tap near the bottom to easily drain the worm tea when it accumulates. This liquid is a valuable nutrient-rich fertilizer.
  5. Assemble the Stack: Place the collection tray at the bottom to catch excess moisture. Stack the three plastic trays on top of each other. The bottom two trays will be used for composting, while the top one will house the active worm bin.
  6. Add Bedding to the Bottom Tray: Fill the bottom tray with dampened organic bedding material. This will provide a suitable habitat for the worms and help retain moisture.
  7. Introduce Worms: Gently introduce the red wiggler worms to the bedding in the bottom tray. Start with a small population to allow them to adjust to their new environment.
  8. Begin Composting: Start adding small amounts of organic kitchen scraps to the bedding. Bury the scraps under the bedding to prevent odor and fruit flies. As the worms consume the scraps, they’ll create vermicompost. Learn how to care for your worms here.
  9. Add Additional Trays: As the bottom tray fills up and the worms migrate upwards, add the second tray on top. Continue this process as the worms process the waste and create compost.
  10. Maintain and Harvest: Regularly monitor the moisture levels in the trays and adjust by adding more damp bedding or water as needed. Harvest vermicompost from the lower trays as it becomes ready. This compost can be used to enrich your garden soil.
  11. Collect Worm Tea: Drain the collected worm tea from the container at the bottom of the stack and use it as a liquid fertilizer for your plants.

Building your own DIY three-tray worm farm can be a rewarding and sustainable project. By repurposing plastic trays, you’re contributing to reducing waste while creating nutrient-rich compost for your garden.

See the detailed instructions on how to build this worm bin here.

Worm baths

You can build worm baths from anything but most people use old bathtubs.


View this excellent article on how to make a worm farm.

Creating a worm farm using an old bathtub and bricks is a creative and resourceful way to repurpose materials for composting. Here’s a step-by-step guide on how to build a worm farm using an old bathtub and bricks:

Materials You’ll Need:

  1. Old bathtub (with drainage hole(s) if possible)
  2. Bricks
  3. Fine mesh or screening material
  4. Organic bedding materials (shredded newspaper, cardboard, coconut coir)
  5. Red wiggler worms (Eisenia fetida)
  6. Organic kitchen scraps
  7. Lid or cover material (optional, to protect from rain and pests)

Step-by-Step Guide:

  1. Choose a Location: Find a suitable and level location in your yard or garden for the old bathtub worm farm. Ensure it’s shaded and protected from direct sunlight and harsh weather conditions.
  2. Create the Base: Place bricks underneath the bathtub to elevate it slightly. This will allow you to put a bucket under the drain hole. The drain must be open at all times preventing waterlogging and ensuring a healthier worm environment.
  3. Prepare the Bathtub Interior: Line the interior of the bathtub with fine mesh or screening material. This prevents worms from escaping through the drainage holes while allowing excess moisture to drain.
  4. Add Bedding: Fill the bathtub with dampened organic bedding material. This will serve as the worms’ living space and aid in moisture retention. Fluff the bedding to create an airy environment. You can use cardboard, compost, soil or a mix of these.
  5. Introduce Worms: Gently introduce the red wiggler worms to the bedding in the bathtub. Start with a small population to allow them to adjust to their new habitat.
  6. Begin Composting: Start adding organic kitchen scraps to the bedding. Bury the scraps within the bedding to avoid odor and attract fewer pests. As the worms consume the scraps, they’ll produce vermicompost. Learn more about this and how to care for your worms here.
  7. Maintain and Monitor: Regularly check the moisture levels in the bathtub. If it gets too dry, add more damp bedding or water. If it’s too wet, consider adjusting the drainage or adding more absorbent bedding. You can also cover the bedding with cardboard and then spray a bit of water onto the cardboard every day.
  8. Optional Lid or Cover: If you want to protect the worm farm from rain and pests, you can create a simple lid using wood, plastic, or any suitable material. Ensure the lid provides enough ventilation while keeping out unwanted visitors. Again cardboard works well also.
  9. Harvest Vermicompost: Over time, the kitchen scraps will be transformed into nutrient-rich vermicompost. Gently sift through the compost to separate the worms from the castings. You can also limit your feeding to one side of the bath and later move your feeding to the other side. The worms will move to the fresh food side and you can harvest the older side. Harvest the vermicompost to use in your garden.
  10. Collect Worm Tea: The worm tea will collect in the bucket beneath the drain. Dilute and use this nutrient-rich liquid as a fertilizer for your plants. You can also make organic insect spray.

Building a worm farm using an old bathtub and bricks offers an excellent way to recycle materials and create a sustainable composting system. It may require a bit more effort in terms of setup, but it can be a unique and effective solution for vermicomposting.

Once you have setup your worm farm in a bin or bath, consider this guide on how to feed and care for them.

Useful Infographic

This picture shows very nicely how to setup and use a worm farm very simple and effectively (from https://www.facebook.com/geofflawtononline):

Worthwhile Videos

How to build a worm bin
Compost worm farming with Geoff Lawton

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