Harvesting and using my vermicompost

I started vermicomposting with 1,000 red worms in an indoor bin a little over a month ago. My last post was about them trying to escape when I first added them... Luckily that ended completely after several days! They have adjusted well to the bin, and not a single worm has crawled out in weeks. They've stayed in the bin, and have been working non-stop to break down all that food. After only a month I've been able to collect a fair amount of rich soil and worm castings.

But first, here's a few things I've learned:

1. Adding food adds most of the moisture you need. Since the ideal moisture level is about that of a wrung-out sponge, you probably won't have to spray down your worm bin with water if you're adding food to it regularly. As plant matter breaks down, it gets wet. Really wet. This also means you have to add some dry stuff to soak it up. By doing this, you'll be able to balance the carbon and nitrogen in your bin without even really thinking about it. If it's too wet or smelly, add some dry stuff like newspaper -- that's the carbon.

2. Some foods break down really fast, and some take a lot longer. I added some watermelon (not the rind but the inside) that went bad and it had disappeared in the span of two days. It's mostly water! Other things that are fibrous take a lot longer to break down, even with the worm's help. The stem of banana peels are one that will still be visible in the bin for over a month. Even when these things are no longer recognizable, you may notice some fibers in your vermicompost. There's nothing wrong with this, you'll notice the same thing in all types of soil!

3. Freezing food waste is a good way to store excess waste in a way that doesn't stink. For instance, if you produce a lot of food waste at once, like say, you carved up a watermelon, you don't want to put all that in at once. So chop it up into little pieces and freeze it. Then take out small amounts at a time, thaw overnight, and feed it to your worms. This has the added benefit of preventing fruit flies and other pests that could be living in your food scraps.

Another thing I've learned is that harvesting is easier than you think! I've harvested in two ways so far, so I'll talk about both of these.

The first is a very quick way to get pure worm castings. This is the most nutrient-dense part of vermicompost -- it's the worm's poop. My worms like to crawl along the sides and inside lid of my bin, so the castings collect along there. When there's a lot, I scrape out the sides and inside of the lid and I end up with maybe a couple tablespoons of pure worm castings. It's not much, but you can do it every few weeks and put a pinch on each of your indoor plants. Then water them to wash the nutrients down into the soil.

Just today, about a month into the life of my bin, I did a more complete harvest and collected about three cups of vermicompost. This was easier than I thought it would be. I put the lid across the bin sideways so half was shaded and then I shoved most of the bin's contents to the shaded side. This left only the bottom layer that was mostly decomposed and very dark in color. The worms will leave this part after a while because of the light, and then you can scoop out the rich, dark soil.

You'll know it's ready because it looks just like soil. You can't recognize anything that went into it, including bedding and food. I had to pick out a couple bits of banana peel and some newspaper strips -- and a lot of worms. It's a little time-consuming to do it this way. If you want to collect a lot more in less time, you can leave in a few worms and bits of stuff that's not completely decomposed. This doesn't really matter if you're putting it on your garden for instance.

But I was planning to use this to pot a plant so I wanted purer compost, and it really didn't take too long to get enough. Here's what it looks like:

Vermicompost in a jar.

As you can see, it looks just like soil. It's also moist -- about the same moisture as a wrung-out sponge, again. If you're not using it immediately, you should try to keep it at this moisture level. If it dries out completely, the microbes will die and it won't be as valuable.

I used about half vermicompost and half potting soil to pot this plant, so if something goes terribly wrong I'll let you know -- but I think the plant, a dracaena marginata, seems happy.

My new plant! Only 2 dollars at IKEA. 

You can see above the difference in color between the potting soil and vermicompost: The vermicompost at the bottom is much darker than the potting soil.

Vermicomposting is definitely like a hobby for me now and I understand why so many people enjoy it. I feed the worms every few days, and I could probably feed them more than I'm currently feeding them, but I'm also sending off some stuff for composting at a different facility -- which means I get to be picky about what I feed them!

The importance of organics composting

People have been composting at home for ages, but city-wide organics collection is a fairly new part of waste management. The concept is pretty new to me too, but I've been learning a lot about it; I've been working toward introducing organics collection at my university for the past few months, and I have a summer internship focused on community outreach about recycling and composting.

And I've realized that composting is not just a new trend, but an essential part of waste management that can combat climate change and bring us toward zero-waste.

Composting is how we can keep organic materials (anything that comes from a plant or animal) from going into a landfill or the ocean, or being burned in an incinerator and polluting the air. This covers all food waste (preventable table scraps as well as non-preventable waste like apples cores, banana peels, etc) and non-recyclable paper products like napkins and paper towels.

You might notice that these are things that break down quickly-- a lot quicker than plastic waste, for instance. So why is it important that organics don't end up in a landfill?

When a bunch of organic matter is in a landfill, it's been compacted together and buried under tons of other waste, and usually sealed with plastic above and below. This is a lot different than just throwing an apple core into the woods.

When organics decompose in a landfill, they decompose anaerobically -- without oxygen. Whereas all decomposition produces carbon dioxide, anaerobic decomposition also produces methane: a greenhouse gas that's actually 20 times more potent than CO2.

And it's not an insignificant amount of methane: Landfills are the number one anthropogenic source of methane emissions.

Additionally, anaerobic conditions can produce leachate, a toxic sludge, that can leak into the groundwater and soil from a landfill. It's bad stuff.

Okay, so what about when food gets into the rivers and oceans, such as through a garbage disposal? (That's where it goes when you wash it down the drain by the way!) Well, that just adds phosphorous and nitrogen to water, which cause algal blooms and dead-zones.

While burning organic waste isn't as bad as these other options, it's still a pollutant and incinerators are usually located in poor neighborhoods, leading to asthma and other respiratory ailments. And I'll remind you, food scraps and paper are not the only things being burned here.

The bottom line is: This stuff shouldn't be waste! We can turn it into a useful and valuable product to use to grow more food. Of course, the value of the compost depends on inputs and the process: compost consisting mostly of food scraps is more nutrient-dense than compost consisting mostly of napkins for instance -- vermicomposting (using worms) produces the most valuable compost out there.

City-collected compost may not yield the most valuable end result, but it still creates a usable product -- and most of all, it reduces waste, combats climate change and pollution. Whether or not there's a ton of economic value in this should be secondary to that.