This is Part III of our DIY In-Ground Worm Composting System series. Be sure to also check out: “DIY In-Ground Worm Composter” and “DIY In-Ground Worm Composter - Summer Update”, if you haven’t already.
With fall in the air, and Bentley visiting the farm (early Oct 2024), we decided it was time to once again check up on our in-ground bucket vermicomposting system, and to provide our readers with an update, including some end-of-season tips/recommendations!
If it wasn’t clear in our July update, this is a system that we’ve “neglected’ a wee bit more than we would typically recommend, and the results - especially by the time we checked most recently - were a demonstration of this.
Although not mandatory, one of the best ways to use an in-ground vermicomposter is as an in situ, natural fertility (and moisture) station for plants. The basic idea is that you install one of these close to where you will be growing plants - typically, seasonal food crops - and the plants then directly benefit from the waste-processing activity of the composting worms.
The trade-off, however, is that the plant roots can take a real toll on the system, especially during the second half of the season. Drier seasons, and less feeding/watering, only amplify this impact.
When we first opened up our bucket, we could tell that the nearby plants had really taken advantage of our revamped late-July system. The overall level of material had dropped considerably, and the contents seemed quite dry and overgrown with roots.
It’s important to note that a vermicomposting system in this state should never be considered devoid of worms. Red Worms, and other composting species, are incredibly resilient - often able to adapt to conditions that are far from ideal. When moisture and food levels drop, they will shrink in size (sometimes almost to the point of being basically invisible) and lay more cocoons - which are even more tolerant of harsh conditions. Both of these strategies help ensure the future survival of the population.
With this in mind, we decided to dump the entire contents of our bucket system into a new backyard composter we happened to be setting up nearby on the same day. This is a great end-of-season option for those who want to start fresh with their in-ground systems (whether it be the next spring or right away).
With our moderate Vancouver Island climate (one of the mildest in Canada), we figured it wouldn’t hurt to get the system going again, especially since it would offer a safe haven for any composting worms that had migrated out of the bucket into the adjacent soil zones.
The hole itself had quite a bit of leftover material in it, so our next step was to completely clean it out (and transfer the contents over to the composter).
Once cleaned out, we added a thick layer of well-aged “triple alder mix” mulch down in the bottom of the hole. This serves as a false bottom below the system to provide the worms with some additional habitat space (if they need it), and also to provide some separation between the bottom of the hole and the system. This can help avoid flooding of the bin during very wet times of year.
Although a cardboard false bottom would likely offer more habitat/food value for the worms, we recommend bulkier, more-resistant materials like wood chips or mulches so as to maintain the structural integrity of this zone for much longer. Given how rotten a lot of our triple alder mix was by the time it was used, it was a near-perfect choice, but even basic wood chips can work well in this zone.
Where we do often recommend a more biodegradable material, such as shredded cardboard, is in the false bottom of the actual bucket (we used cardboard when we first set up this bucket back in the spring). This time around we opted to simply use more of the rotten alder mix, since we had a lot of it on hand and (as touched on) it’s really nice stuff.
NOTE: Always remember that there are a wide range of materials that can work very well in these systems (and most vermicomposting systems, especially outdoors). One of the best approaches is simply to take advantage of the materials you have good local access to (i.e. it’s definitely not mandatory to use the exact same materials we’ve been using).
Next, it was time for a material that is more biodegradable - and also likely better for water retention (especially as it starts breaking down) - hemp tow.
Then, we added some worm-rich material from another system. Aside from providing a new starter population of Red Worms (and some nice habitat for them), this was also an excellent living material to help boost the population of beneficial microbes.
More tow was layered in over top, before laying down a layer of water-rich food wastes.
Next up was a layer of aged bedded horse manure, which offers excellent food and habitat value for the worms (and, once again, loads of helpful microbes).
The uppermost layer was old straw. This offers good insulation value while still helping with airflow.
The final set-up step - which could have been done any time after the false bottom was added and the bucket was in the hole - involved stuffing all the extra space in the hole with more of the decomposed mulch mix.
With the set-up complete, the system was watered thoroughly (remember, there is excellent drainage, so you can give it a good soaking) and the lid was once again secured in place.
If you live in an area that is a bit colder, one additional step you may want to take is heaping more browns - such as straw or fall leaves - over the closed lid as well. This, plus any snow that falls, should provide quite a bit of extra insulation for the system.
We’ve opted to leave our bucket exposed, and may even add some additional deposits between now and spring!
Key Take-Aways
- DIY bucket worm composters are an easy and inexpensive way to compost directly in your gardens and other outdoor soil zones.
- Aside from allowing the plants easier access to the nutrient- and microbe-rich contents, they offer more protection from the elements than most above-ground systems. (Just keep in mind that direct plant access can lead to root invasion and some moisture management challenges during the active growing season).
- A wide range of materials can be used in these systems. If possible, aim for a diversity of locally-available “greens”, “browns” and living materials.
- Materials should be added in layers, starting with a thicker false bottom (both outside and inside the bucket) and ending with a cover bedding layer.
- These systems can be stocked effectively with smaller quantities of composting worms, either as bulk worms (we recommend ⅛ to ¼ lb at most), or in the form of worm-rich material from another system.
- Watering and feeding every 1-3 weeks can help the worm population thrive, but in-ground bucket systems are quite tolerant of neglect (especially earlier in the season and during colder months).
- Depending on your local climate, you may opt to completely empty out your bucket in the fall and start fresh in the spring, or restart it for a slower composting process over the winter.
Helpful Related Resources
DIY In-Ground Worm Composter
DIY In-Ground Worm Composter - Summer Update
The Plastia In-Ground Worm Composter
Outdoor Cold Weather Composting
Can I Add Red Wigglers to My Garden?
Outdoor Vermicomposting 101
What Is “Living Material”?
Bedding - The Most Important Material in Your Worm Bin?
Recommended Products
Red Wigglers
Urbalive In-Ground Worm Composter
GeoBin
pH Buffer Grit
EM Concentrate