In Part I of our Urban Worm Bag series, we looked at the pros and cons of this system. In Part II we shared our recommended set up approach for UWBs. In this final installment, we will be zoning in on topics relating to the ongoing care and harvesting of an Urban Worm Bag.
Feeding Your Urban Worm Bag
Once the set up process is complete, and your worms have been added to the system, it’s important to wait at least a few days before introducing more food. Just generally, you should err on the side of “too little” food (maybe a few handfuls a week), and use the processing speed of your worms as the main deciding factor for adding new deposits.
I.E. If the worms seem to be consuming what you’ve added, you should be ok to add some more. Do not add food based on the amount of waste the worms are “supposed” to consume daily/weekly. There are a wide range of factors that can heavily influence system processing speeds.
Various forms of food optimization can greatly help the process along. If possible, it’s best to chop up your wastes into small pieces, since this greatly increases the surface area for microbial colonization. Leaving scraps to sit (ideally in a container with some bedding and good airflow) for a period of time before feeding can also help. Freezing/thawing your more resistant scraps is yet another way to help kickstart the breakdown process.
The good news is that the Urban Worm Bag is a very forgiving system. Thanks to the larger size, and ample airflow, even overfeeding it accidentally from time to time shouldn’t cause any major issues, especially if you are regularly adding new bedding and living material. It’s important to note that the larger size of this system will make it more prone to microbial heating, so we highly recommend monitoring temperatures on a regular basis (with an aim to keep them in the 17 to 26 C range as much as possible).
Urban Worm Bag Troubleshooting
As touched on, the UWB tends to be a pretty forgiving home-scale worm bin, but like any vermicomposting system, there can still be some potential hiccups along the way, even under the best of circumstances. In this section we will look at some of the most common issues that people can encounter.
Lots of Flies
Flying “pests” can be one of the most frustrating aspects of worm composting, so it is good to prepare yourself for this, especially during warmer parts of the year. As touched on in Part II of this article series, we strongly emphasize the importance of adding a thick layer of cover bedding - potentially even with some form of worm blanket directly over top of the worm zone. This can be a good preventative measure, and also a way to reduce their escape once the flies get established.
If you do end up with a bad infestation of small flies or gnats, we recommend starting by removing as much unprocessed food material from the system as possible. This is likely loaded with eggs and larvae, and it will continue to boost the population of the adults if left in place. This can be placed in a bag in your freezer where the eggs/larvae will be killed, and it can stay there until you are ready to add it to the system again.
As funny as it might sound, a really great way to quickly reduce a large population of adults is with a vacuum. What’s great about the UWB is that you can even open up the lid just enough to get your vacuum pipe inside (just be careful if your cover bedding materials are up towards the top of the system - you don’t want to suck all those up). These brief vacuuming sessions done daily, over a period of time, can be a great way to bring about a population crash (especially when combined with other strategies).
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Lots of Crawling Organisms
Having a diverse ecosystem of different organisms in a worm composting system is highly valuable for your ongoing success. That said, if you are seeing huge explosions of one or more organisms, other than the worms, it likely means the system is out of balance. The most common culprit is overfeeding (adding too much food at once, or adding deposits too often).
A lot of the “usual suspects” that can show up are simply effective opportunists who are able to take advantage of large food supplies very quickly.
Similar to the situation with flying pests, a good starting place can be to transfer most or all of the unprocessed food to a bag and toss it in the freezer (just be careful not to include any of your worms). Next, it will be a good idea to add even more cover bedding, and then leave the system to sit without additional feeding for 5-7 days. The worms will happily munch away on partially decomposed bedding materials, but most of the other abundant organisms should fade away fairly quickly.
Again, we are NOT trying to eradicate other organisms from the system, but rather to achieve more of a balanced ecosystem.
NOTE: One of the great benefits of using high quality living materials, such as aged bedded horse manure and decomposed leaf litter, in your worm bins is it can help you achieve and maintain more of an ecosystem balance. These materials tend to have a very diverse group of organisms in them, including helpful predators that can keep some of the “pest” organisms in check.
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Lots of Liquid Draining Out from Bottom
As touched on in our set-up article, it is not uncommon to end up with at least some drainage out from the bottom of an Urban Worm Bag, even when using our 3-part false bottom strategy. So, we recommend always keeping some sort of catch bucket or bin down below, just in case.
If you are finding that a lot of draining liquid is accumulating in your container, some additional steps should be taken in order to achieve proper moisture management.
Firstly, while you certainly can occasionally spritz the contents of your Urban Worm Bag with a spray bottle - especially if it seems like materials up towards the top (underneath cover bedding) are drying out - you should avoid adding a lot of water at once, and it is best to never actually pour it into the system.
Hopefully it goes without saying that you should absolutely never pour water through your UWB to make a “worm tea” (much better to produce high quality castings and then make teas and extracts from this material).
Another cause of excessively wet conditions can be overfeeding with lots of water-rich fruit/veggie wastes. Typically, you will also notice other issues, such as funky smells, and outbreaks of certain organisms. Once again, it can be helpful to remove excess food, add more bedding (LMs too if you have them), and hold off on feeding for a while.
Keeping your lid partially or even fully open (with a really thick cover bedding layer) can also help with moisture management when conditions seem to be excessively wet.
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Bad Odours
As alluded to in the last section, this is another issue that can be closely linked to overfeeding and/or excessively wet conditions. It is less common in a well-ventilated system like the UWB, but it can still happen.
More bedding, removing excess food (and not feeding for a period of time), more airflow, more living materials…you know the drill! 😉
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Worms Climbing Up the Walls
For a bag system, the Urban Worm Bag retains moisture quite well, so humidity can be fairly high in the upper zone - even potentially to the point where you will see a lot of condensation on the side walls. Moist, dark environments tend to be inviting for your worms, so it is not uncommon to see some roaming around on the walls when the lid is closed.
If it looks like more of a mass exodus attempt than simply a handful of worms exploring, it may indicate that something is going wrong further down. Very often, it will relate to the food you’ve been adding. A common issue is too much food for the system, which can lead to harmful compounds being produced, or excess heating which can also be dangerous for the worms.
As always, remove as much extra food as you can, add more bedding, improve airflow (maybe even blow a fan over the system with the lid open), add living material if you have some and hold off on feeding for a while.
NOTE: Maintaining a really thick layer of dry cover bedding is actually a great way to reduce worm roaming, especially if you leave your lid at least partially open, since it tends to keep that upper zone too dry (and too well lit, if lid open) for the worms.
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Slow Waste Processing
A good place to start is by tempering your expectations. In other words, don’t assume the worms are going to consume some specific amount of waste per specific amount of time (eg half their weight in wastes etc).
There are many different factors that have a major impact on the processing speed of a vermicomposting system. Temperature, moisture content, airflow, and optimization efforts (if any), are some of the most significant ones. Of these, cooler temperatures - anything down below 20 C - can be one of the most common culprits, since it can greatly slow down the activity of the microbes and worms.
In terms of optimization, basically anything you can do to help the microbes and worms will also tend to speed up waste processing. Chopping up your food materials really well, letting them sit (ideally mixed with bedding) for a period of time before using them, freezing/thawing them - these can all help the process along. Mixing your wastes with living materials can help to get a lot more beneficial microbes where you need them, so this is a great strategy as well.
Moisture content and airflow tend to be inversely related in a worm composting system. The goal is always to have a well ventilated system with damp habitat materials. Too much airflow tends to dry things out too much (which can also slow down the process). Too much moisture impedes oxygenation. Luckily, in the case of the UWB, it tends to be easier to maintain a good airflow/moisture balance in comparison to plastic tub (and similar) systems
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Harvesting Issues
See the next section for more info about harvesting (including some potential issues you may encounter)
Harvesting Castings from Your Urban Worm Bag
Once your Urban Worm Bag is about ¾ full of rich, earthy looking (and smelling) material, it is time for your first harvest of castings. This initial “priming” period will likely take at least 3 to 4 months, but quite possibly longer.
As touched on in our set-up article, your first step will likely involve emptying out all the loose bedding that was placed in the bottom pocket. You may or may not also need to scrape out the thin paper/newsprint layer with a small rake or garden fork. Either way, by this point the castings down in the bottom should be nicely compressed and formed to the walls of the system, so you shouldn’t need to worry about everything just falling out (the only way this will happen is if you have neglected the system to the point of everything mostly drying out).
As is the case with feeding, we always recommend erring on the side of smaller amounts with your harvesting efforts as well, since more aggressive harvesting can result in the release of worms and unprocessed materials from further up in the system. It’s hard to provide recommendations for exact amounts you can remove (once again, this is something that is dependent on a wide range of factors), but you should be ok to remove 2 or 3 litres of it.
NOTE: Depending on your system management practices, it’s not uncommon for the material at the bottom of your UWB to be damp, and for there to even be some worms in it. If it is really wet and/or there seems to be a lot of worms in the material, we recommend leaving the bottom open (with a bucket or bin sitting below it) - and letting everything air out for a number of days. Using a fan to blow air across this zone can help to speed up the drying process, and should also discourage worms from crawling out.
With your first harvest out of the way, you should then be able to continue harvesting modest amounts of castings from the more regularly - maybe every month or two. If it seems like your overall level of rich, dark material in the system is remaining quite high up, you should be ok to harvest more. After a harvest, you should see the overall level in the system drop down within a day or two (maybe sooner).
Final Thoughts
If you made it all the way through our 3-part Urban Worm Bag series, you should now have a very solid understanding of: A) whether it is the right system for you and your situation, B) how to set it up for an increased chance of vermicomposting success, and C) how to care for and harvest the system effectively over time.
If you have any questions relating to UWBs, or anything else in the realm of composting, please don’t hesitate to reach out anytime! We’d love to hear from you! 😎
In the meantime, happy worm composting!
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The Urban Worm Bag - Our Most (Under-the-Radar) Recommended Home System?
Setting Up Your Urban Worm Bag for Worm Composting Success!
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What Is “Living Material”?
Bedding - The Most Important Material in Your Worm Bin?
Common Questions About Harvesting Worm Castings
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