Setting Up Your Urban Worm Bag for Worm Composting Success!
This is Part II in our 3-part Urban Worm Bag series. If you want to start with an overview of the pros and cons of the UWB system, be sure to check out: The Urban Worm Bag - Our Most (Under-the-Radar) Recommended Home System?
In this installment we will be digging in with the actual set-up process for this bin. Well, at least the way we encourage people to do it! 😉
Our approach involves a 3-section set-up strategy - somewhat similar to what we recommend for tub systems, but with some unique differences catered to the UWB design.
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False Bottom - This is the zone down in the very bottom of the system, where dry, bulky, absorbent bedding materials can play an important role in moisture and airflow management. Unlike in a tub system, some of this bedding will be removed completely intact during the first harvest (and can simply be added back at the top).
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Worm Zone - This middle zone is where most of the action happens and - as the name implies - where most of the worms will be hanging out (at least early on). Over time, this zone should shift upwards in the system.
- Cover Bedding - This is the uppermost, ideally thick, layer of bedding materials (which can include some form of worm blanket as well). The purpose of these materials is to help reduce moisture loss in the worm zone, discourage pests, and to provide you with an ongoing supply of loose bedding that can be mixed with your food deposits.
We’ll now expand on each of these as we walk you through our recommended set up process!
False Bottom
At the very bottom of the Urban Worm Bag, there is a pocket that extends down from the main compartment. It features a heavy-duty removable cover that can help to keep things even more contained. Our preference is to actually take this off, so as to provide more airflow for the lower reaches of the system (this can make a big difference once it comes time to harvest).
The pocket itself is made from a durable-yet-breathable, lightweight fabric, and is opened and closed easily with a plastic toggle. We recommend filling this zone with dry, absorbent bedding such as shredded cardboard. This will help you soak up excess moisture that drips down, and also provides some separation between the composting zone and the lower opening (which will be even more important early on).
NOTE: There is actually no expectation that this bedding will break down (it most likely won’t). During your first harvest, you can simply collect it, along with any other unprocessed or semi-processed bedding, and deposit it back into the system up above.
Over top of our pocket bedding, it’s very helpful to add sheets of newspaper, or blank newsprint, or kraft paper (the latter two being much better choices). These layers should be moistened enough so they to stick to the side walls. The idea here is to basically contain the composting zone during the early stages of the process. This will help prevent worms, and other organisms, from moving down into the pocket zone (and potentially out of the system). It should also reduce the amount of liquid draining out. Similar to the pocket bedding, it’s not critical for this material to fully decompose. It can easily be raked out during the harvesting process (and recycled as a bedding / living material further up in the system).
Our final false bottom layer consists of a generous deposit of bulky, absorbent bedding materials. This bedding will, once again, help with moisture management, but it will also help to balance out our initial food deposits. Just generally, it will contribute to the overall quality of the worms’ habitat during the early stages of the process. Unlike the other two sections of the false bottom, this bedding will more than likely be completely converted into vermicast over time.
Worm Zone
With our false bottom complete, it’s time to start putting together the worm zone. Ideally, this will be mostly made up of bedding and living materials (our two main types of "safe habitat materials"), along with a smaller quantity of food. Aim for a ratio of at least 2:1; safe materials vs food.
NOTE: The habitat:food ratio we're aiming for in the entire system is more like 4:1.
A good starting place for your worm zone is with a healthy deposit of living material (LM) directly over the false bottom. If you are not familiar with the LM concept, please be sure to check out our What is “Living Material”? blog post for an in-depth look at the topic.
Next, you can add a thin layer of food materials. It’s ok to cover the entire surface, but aim to keep it to an inch or less in depth.
The image below makes it look like a lot of food was added during the set up process for this particular UWB, but it was actually a more moderate amount of food that had already been mixed with some living material and bedding.
This food/habitat mix was then covered with even more living habitat material (mostly semi-rotten bedding). It’s always helpful to sandwich food layers in between layers of these much more stable habitat materials. Things just tend to go more smoothly, and the system as a whole will be more forgiving.
Although not mandatory, adding amendments like our pH buffer grit and/or biochar can also help to enhance your worm habitat. Lightly sprinkling them over the surface of your food layer is a great way to add them during the set up process.
Obviously, we can’t forget about the worms - this is the “worm zone” after all! When and how you add them, and how many you add will depend on a few important factors.
We often like to use a “good, better, best” model of assessment for a wide range of things relating to composting, including setting up systems and adding worms!
Let’s consider it specifically in the context of setting up an Urban Worm Bag:
In simplified terms, you might think of “good” (a very common approach) as getting the system set up with a nice ratio of bedding materials to food materials (always aim for somewhere between 70/30 and 80/20 habitat/food), and stocking it with worms bought from a supplier.
The “better” level would be very similar (including the worm stocking), but instead of only using bedding for your habitat materials, you would also incorporate plenty of quality, microbe-loaded living materials too!
The “best” case scenario here would involve adding a lot of worm-rich material from another thriving system, or even emptying an entire system into the UWB to get it started.
This is probably a good place to mention that the system featured in our photo series here was started using what we’ve designated as the “best” approach. Another thriving system was literally dumped into the UWB (some in the bottom of the worm zone, the rest up above the food layer), providing it with a full worm composting ecosystem (including loads of worms, of course), living material, even some really nice older bedding materials.
We realize this likely won’t be an option for a lot of readers, so it’s important to chat about the other two scenarios as well!
If you only have access to regular bedding and typical food materials (eg compostable kitchen scraps), we recommend simply sandwiching your initial food layer in between 2 layers of bedding. In this case, we also recommend letting the system age for 5 to 7 days before stocking it with your worms. The quantity of worms we recommend for the UWB (when added in bulk) is ½ lb to 1 lb. This might seem to be on the low side for a system this big, but we always encourage growing your worm population more naturally, so you end up with a quantity of worms perfectly suited for your particular system and conditions!
Moving on…
If you do at least have access some quality living material (e.g. really old leaf mulch, well aged, bedded horse manure etc), our suggestion would be to sandwich your thin food layer in between two layers of LM (it should be a “primary LM” - i.e. a “habitat-grade” living material - again, we highly recommend reading the LM article if you are new to this topic). The good news in this case is that it won’t be quite as important to let the system age before adding your worms. You might wait 2 or 3 days if you want to err on the side of caution, but with a decent amount of living material in the system, the environment should feel a lot more like “home” for the worms, and they will likely settle in a lot more quickly.
It’s important for your worm zone to be nice and moist - somewhere in the range of 50-70% moisture content will be ideal. The habitat should be damp to the touch, but not dripping-wet. You can moisten your materials with water, or even a dilute (100:1) EM mixture, before adding them, or simply spray them down as you layer them in.
Cover Bedding
The final section of our 3-section set-up model is the incredibly important - yet often neglected - cover bedding zone. This is where you should add a nice thick (3” or more) layer of dry, bulky, bedding materials, such as shredded cardboard, coco coir or hemp tow. Even better, we often recommend a combination of all 3 (and/or other materials)!
This is also a great zone to add some form of worm blanket. We recommend adding this directly over the worm zone, with the loose cover bedding heaped over top. These blankets are completely optional, but they can add an additional level of moisture retention and pest protection to help keep things humming along beautifully down below. The hemp worm blankets we sell break down more quickly than blankets made of jute or coir, but they are better for short-term habitat enhancement, and balancing out the food deposits. Worms really seem to be drawn to the hemp fibres as they break down, so it likely won’t be long before you see lots of them concentrated directly below it (even starting to crawl right into it).
NOTE: The light-coloured paper in the image below is blank newsprint paper, often used in a packing material for shipping. We recommend a “scrunched” treatment vs a shredded version, since the latter can end up matting together, potentially limiting airflow. It’s also worth noting that we recommend avoiding the use of white (bleached) office paper as much as possible, since it can contain a range of different chemicals we won’t want in the system. Same goes for coloured newsprint. As alluded to earlier, one minor exception to this rule is if you don’t have access to blank newsprint or sheets of kraft paper for your bottom cover (middle false bottom layer).
By the time you have added the cover bedding layer, the overall level in the system should be up towards ½ or ¾ full. Remember that the vast majority of this material should be in the “safe habitat” category (bedding and living material), with only a modest amount of food to start.
Summing Up
- We recommend a 3-section set-up model for the Urban Worm Bag: 1) False Bottom, 2) Worm Zone, 3) Cover Bedding.
- The (UWB) false bottom itself has 3 sections: 1) loose pocket bedding, 2) paper sheet bedding, and 3) upper loose bedding (nice and thick). These greatly help with moisture management and keeping system contents (and residents) contained.
- The Worm Zone is where we add even more bedding, ideally some living materials (LMs), a modest amount of starter food, and of course the worms.
- Aim for a 2:1 (or higher) ratio of safe habitat materials (bedding and LMs) to food materials, with your food sandwiched in between safe materials. All habitat materials should be fairly damp but not sopping wet (50-70% moisture).
- If you don’t have LMs and are stocking with purchased worms, use bedding for all your safe habitat material, and let everything age for 5-7 days before adding the worms.
- If you do have LMs, include these with your bedding. You should be able to add the worms after 1-3 days (since the LMs will greatly help the development of a microbial population).
- The absolute best way to start up an Urban Worm Bag is by using a lot of worm-rich material from another thriving system, or even just dumping in the entire contents from a smaller system. This way you get lots of living material, and worms (and ecosystem), likely even some bedding all in one shot.
- The Cover Bedding zone is where you add (and maintain) a nice thick layer - 3” or more - of loose bedding materials. Using some form of worm blanket directly over the worm zone and under the loose bedding is a great strategy as well.
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For information relating to the ongoing care of your Urban Worm Bag, be sure to check out Part III in this series: How to Maintain and Harvest Your Urban Worm Bag.
Helpful Related Articles
The Urban Worm Bag - Our Most (Under-the-Radar) Recommended Home System
How to Feed Your Worms to Get The Best Results From Your Worm Bin
Smelly Worm Bins - Possible Causes & Effective Solutions
What Is “Living Material”?
Bedding - The Most Important Material in Your Worm Bin?
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