Learning to compost, part 3: the worm bin

In an earlier post, I mentioned the small bucket of worms that we’ve had under our sink for the last year and half. At first, I didn’t know much about how to take care of them, and they didn’t exactly thrive. We encountered several different problems with the worms over time.

First, the worms were not able to process our food scraps quickly enough, so we ended up putting most of our scraps in the trash. At one point, we got a pretty bad infestation of fruit flies which was annoying and took some time to get rid of. At another time we found that we had an excess of moisture in the bucket, which caused the worms to crawl up the side and try to flee. Related to this problem, the bin started to smell due to food that was rotting rather than being consumed.

After doing some reading, I’ve learned that all of these problems can be easily avoided by using a proper container and bedding material.

The key to an effective worm bin is aeration. Worms need a humid environment. If they dry out too much, they can no longer breathe through their skin and will die. However, too much moisture can cause the bedding to become compacted and prevent airflow. Without enough oxygen, worms will suffocate. Also, anerobic bacteria will develop which is what produces the awful smell of methane.

For these reasons, worm bins need to have some drainage on the bottom and plenty of surface area on the top to allow air flow. Rectangular tubs are thus much preferred to buckets because they allow for better airflow.

As I started learning about various types of worm containers, I became aware of these commercial worm bins that can be purchased online. In addition to optimal drainage and ventilation, the killer feature of these bins is that they use a system of stackable trays to make harvesting compost much easier. As the worms start to produce a lot of compost, you gradually start feeding the trays above. The worms will migrate upwards towards the new food, conveniently leaving behind the tray of compost to be emptied.

Since I’m sucker for convenience (and an Amazon addict), I was strongly tempted to purchase one of these things. However, I wasn’t too excited to shell out $80-100 for a couple plastic trays. Also, the idea of purchasing a new manufactured product seemed counter to the spirit of this project––which is sustainability, after all. Luckily, I found the ticket to a DIY solution when the IU Surplus Store posted these perfect used plastic bins for sale.

These things are perfect in just about every way. They are rectangular, stackable, and already have holes for worm and air movement. I was even able to grab one without holes to use as the bottom tray where liquid collects. Best of all, they cost a whopping 20 cents each! Before transferring the worms I just had to make one small modification. For the starting holding tray (second from the bottom), I added some window screen material in order to prevent worms or any solid material from faling below.

Next step: transfer the worms and start feeding them.

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