DIY-In Ground Worm Bin

With all the extra time spent at home, might as well spend it improving your garden soil, decreasing your waste, and giving your kids some fun new pets right? Seriously, kids LOVE worms! And a DIY in-ground worm bin is a very economical way to provide long-lasting slow release soil amendment to your plants. It’s super easy to do, and the kiddos can help. My 4 year old had a blast playing with worms, learning about what a drill does, and digging in the dirt.  

As you likely know, composting is a great way to improve your soil, while recycling your food and yard waste. It’s nature’s way of recycling! Why in-ground vs. typical composting? I personally have a traditional compost bin and a typical worm bin (above ground). For me, vermicomposting (composting with worms) is great given worms are voracious eaters of food waste and my family creates more food waste than yard waste. But, I find with toddlers running around my home, that I rarely have time to harvest my worm bin appropriately. An in-ground worm bin is one where you still add the compostables to the bin, but the worms will travel in and out of the bin and therefore spread their castings (wonderful worm poop) into your garden, improving your soil all the while. Also, if you forget to feed them for a time, they have a chance to travel into the garden to find some food for themselves (don’t worry, they won’t damage your plants either). Yes it takes up a little bit of precious garden space, but I think it’s worth it. These hard working worms certainly earn their keep! Supplies: 

• 5 gallon bucket with secure lid 
• Drill with ½ inch drill bit/spade bit 

• Red wiggler worms (eisenia fetida) available at many garden nurseries or neighbors who vermicompost 
• Compostable materials 
• Ideally some type of bedding/substrate for the worms such as coconut coir, shredded paper, or leaf litter  
• Shovel for digging 

Directions: 

1. Find an appropriate spot in your garden to dig a hole that will fit your 5 gallon bucket. If the area has not been dug before, or is not in a raised bed, be sure to consider calling 811 before doing any digging to ensure safety. Be mindful of your current plants/trees root systems as well. Make sure the 5 gallon bucket fits nicely in the hole and the lid still sits slightly above the soil line when set in.
2.  Drill approximately 20 evenly spaced holes in the side of the bucket and about 10 on the bottom of the bucket. NONE on the top! 
3. Soak some shredded paper, or dampen some leaf litter or coconut coir, as a starter bedding for your red wiggler worms. Also add a little bit of sand or soil to provide them the grit they need to digest their food since worms lack teeth. 
4. Add in your compostables (more on this later) and then the bedding on top 
5. Add your worms, put on your lid and put the bucket in the hole. Make sure to back fill any open space around the bucket to ensure the soil touches the sides. 
6. Give yourself a pat on the back for doing something good for the environment, your soil and plants, and saving yourself some money on future soil amendments

 What to put in your bin: 

A worm bin is especially great for fruit and vegetable scraps. Worms can also eat some plant material, but nothing too woody or tough. Worms are partial to soft foods so you’ll see soft foods like avocado, melon rinds, bananas, apples, and berries disappear quickly. However, they don’t seem to like tougher things like broccoli or strong smelling things like onion or garlic as much so those might take longer. Don’t worry though, worms aren’t the only superheroes in your bin. Many small organisms, some you can’t even see, are working hard to turn your food/plant waste into garden gold. Coffee grounds are also fine in moderate amounts, just make sure it doesn’t make up too much of your bin space. Paper towels, coffee filters, torn up cardboard, a little bit of bread here and there…all fine.  

That said, there are some items you should NOT add to your bin.  Do NOT add much if any citrus. Citrus (lemons, lime, oranges) have an oil in the rind that is harmful to worms in large amounts. I save citrus mostly for my traditional compost bin. Don’t add eggs, oil, dairy products, or meat (it’s stinky and can potentially introduce harmful bacteria). Oil doesn’t break down so if your burnt asparagus is drenched in oil, into the trash it goes. Same is true for that cheesy broccoli…trash can bound.  

Plants are generally fine to add as long as they aren’t too woody (lignin is hard to break down).  Diseased plants are also a no go (don’t want to add diseases back into your soil), or weeds that have gone to seed. Be careful with mown grass clippings too. Fresh grass clippings can get very hot and make the temperature too hot for worms. If you let your clippings dry out before adding them, that should be fine. Harvesting: 

The goal of the in-ground worm bin is to let it work on it’s own for longer than a typical above ground worm bin. The nice thing about composting is that even if you fill up the bucket, the act of decomposition decreases the product you put in by about half. So as things are composted you’ll see the bin level dropping and you can add more as you go. That said, castings (worm poop) can get kind of thick and fudgy if you leave it in the worm bin for too long. So eventually you probably want to empty the bin (feed a tree!)..  

You can stop adding compostables to the worm bin for about 2-4 weeks prior to harvesting. This allows worms to finish up the current compostables, and then many of them will hopefully move into the garden bed to look for more food. At this point you’ll remove the bucket from the ground and empty the contents onto plants or trees. Then simply start new bedding, add compostables and return the bucket to the ground and hope many of your worm friends return quickly. If using this method, it’s inevitable that some worms will stick around inside the bucket and get emptied out along with your lovely finished compost. To avoid losing any worms, you can use a sifter/screen or hardware cloth above a bin or wheelbarrow which allows the finished compost to go through, but catches the worms to be returned to the bucket.  Additional Notes: 

• Yes, it should be red wiggler/compost worms that you use. Not all earthworms are created equal for this job. Your typical nightcrawler earthworms are great, but not as good for this task. Red wiggler worms are voracious eaters and can eat up to half their body weight in a day so they are superstars at eating our food waste. They also are homebodies so will stay in the bin if the food is there instead of wandering about the garden. 
• Check on the moisture level of your worms from time to time. The dampness should feel as wet as a wrung out sponge. If it drips when you squeeze it, it’s too wet. If it feels dry, add water.  

• Once you set up the worm bin, let the worms settle for a few days before bothering them, or adding more food. The frequency and amount of food you add depends on how many worms you have in the bin. You’ll start to get a feel for how fast your worms are composting and adjust accordingly.  

Happy vermicomposting!