Dec 15, 2017

Raise Your Own Worms – Vermicomposting

In the Diggin’ Earthworms article, we learned about worms and what their presence means for your garden and the soil in general. I mentioned that you can raise your own worms to help compost your food and paper waste. Today I’ll give you step-by-step instructions on how to build a worm bin, and how to raise your own worms to help compost food and paper waste!!


You will need:

  • 2 plastic totes (14-18 gallon). One bin with a tight-fitting lid, and make sure they close stack (similar to the picture, I believe those are Rubbermaid brand)
  • Window screen material
  • Duct tape
  • Distilled Water or Rainwater
  • 1 cup of sand
  • Shredded newspaper or regular paper (no glossy advertising paper or colored ink), in approximately 1” strips, or run through a paper shredder
  • Electric drill with 1/4” bit
  • 2 pounds of worms (or as many as you can find in the garden!)
  • 1-2 pounds of kitchen scraps, cut into small pieces


Using the drill and bit, evenly space holes around the outside of one of the bins, about 4” from the top of the bin. Drill another 5 holes in the bottom (in an X pattern).

Line the bottom with screen and tape it down. This keeps the worms from escaping and allows compost tea to drain down and be accessible when you want it.

Place the bin with holes inside the bin without holes, and take a pen and mark the sides of the outer bin through the holes in the inner bin. Drill out the holes in the outer bin so they line up with the holes in the inner bin.  Don’t drill the bottom of the outer bin!

Duct tape screening over the sidewall holes in the inner bin. This will also keep your worms from escaping.


Set Up:

Cut the paper into 1” strips. Thoroughly wet the paper so that it is like a wet sponge, but not dripping (you can squeeze excess water out). Fill the inner bin about ⅔ full of paper. This serves as bedding and food for the worms.

Evenly spread the 1 cup of sand, as well as kitchen scraps, over the paper.

Add the worms to the top. Place the lid to close the worm box, and you’re done with setup!

You can increase or decrease the size of your worm bins from what is described. I have seen people use a stack of 5-gallon buckets and it worked well for them (small households, or apartments where outdoor space is at a premium), and I’ve seen enormous bins as well. As long as the worms have their three essentials – food, water, air – they will be just fine.


Eligible Scraps to Feed Your Worms

  • Coffee grounds with the paper filter
  • Tea bags (no staple)
  • Shredded paper (black ink newspaper only, no color or glossy ads)
  • Cooked pasta
  • Fruit and vegetable scraps (try to avoid onions and garlic)
  • Crushed egg shells
  • Bread
  • Cardboard
  • Untreated grass and leaf clippings (no pesticides/chemicals)
  • Small amounts of untreated wood chips/shavings/sawdust at a time

Remember that the smaller the pieces of scrap you add, the faster the worms can convert it to castings!


Maintaining the Worm Bed

Worms like it best between 60-80 degrees, but they will tolerate colder or warmer weather. They are very independent little workers, all they really need is food, air, and water. Troubleshooting is easy!

  • If their environment gets compacted, you can fluff everything up gently to give them a little more room to move around (unless it’s cold outside, then just leave them be).
  • If the soil is too wet, give them more shredded paper bedding (it will wick up the water). If it’s too dry, give them a little water, or water-laden kitchen scraps like tomatoes and cucumbers.

When it’s time to harvest castings (your bin will be quite full of castings, and you’ll need to make room for more!), you’ll need to feed the worms on one side of the bed only, and move all visible food to that side as well. Give the worms a couple of days to travel to that one side. Then, scoop out the castings on the other side. Try to remove as many worms as you can to put back in the bin, but don’t worry if you don’t get them all. Redistribute the remaining castings evenly in the bin so the surface is flat again. Spread the castings you collected into your garden and scratch them in around the roots of plants and such. Lightly water them in, or if you know rain is coming, just wait. Your plants will love it!

The Bottom Bin – The Compost Tea Collector

There’s this magical stuff called “compost tea” that comes as a byproduct of vermiculture. It is a nutrient-rich liquid that filters down through the compost, and contains the more liquid parts of your worm’s castings. After some time has passed with your worms hard at work, you can lift the worm bed out of the bottom container and you should see some brown/black liquid in the bottom of the outer container. I recommend using compost tea for plant pick-me ups, as the nutrients in the tea are very bio-available to the plants. Take the liquid from your bin and make a half and half mix with water. Use it to water plants as needed for extra nutrition, taking the place of watering that day. They will thank you! Check your compost tea bin every 3-4 weeks, sooner if you have been using the worm composter very heavily (like a pound or more of scraps every single day). You can use compost tea not only in your garden, but in houseplants, landscaping, and for trees.

Final Tips

If you have a smaller bin and it is going to freeze, try to move it inside if possible, or insulate it. Worms can survive cold weather, but if the soil freezes they aren’t going to do so well. Small containers are more likely to freeze than large ones simply due to volume versus their container’s exposure to surface air. If there is enough decay in the system, it will be less likely to freeze because of the heat generated from rotting. But just to be safe, think of your worms in a freeze.

If you just have a single worm bin, you can still make compost tea. A couple of days before you want the tea, put new food on one side of the bin, and push any food from previous feedings to the same side as you put the new food. Worms will travel to the new smell over a couple of days, leaving one side with less worms. From that “vacated” side, take a volleyball-sized amount of the castings, or as much as you have there, and try to remove as many worms and/or worm eggs as you can find. Wrap it in cheesecloth and tie a handle of some kind on it (like a rope). Place the casting ball into a 5 gallon bucket and fill the bucket. Let it sit overnight. The next day, take the castings out, and spread in your garden, lawn or landscape. Use the compost tea in a sprayer for soil and foliar feeding of your plants/shrubs/trees, or just use it to water from the bucket.

I hope you’ll try your hand at Vermiculture and Vermicomposting! It’s really fun, and a great way to keep trash out of the landfills while getting an organic source of nutrients for your beloved plants. And, you get a few more “kids” to take care of.   There are lots more bin designs and configurations out there, so feel free to just use this as a basic guide and experiment with other types of bins too! Enjoy! – Marissa

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