One question we hear quite often at Uncle Jim’s Worm Farm is, “What should I do with the liquid that drains off my worm bin? Is that worm tea?”
First off, properly speaking, the liquid that drains from the spigot is not worm compost tea, although some people do call it that. The liquid that drains from the bottom of a worm bin is more accurately called worm leachate or worm seepage.
So What Is Worm Leachate?
Worm wee. Wait, do worms pee? No. So how is worm leachate worm wee then? Simply because some people call it that. Somewhat incorrectly. To get serious – worms release extra water through the pores on their bodies, similar to how we sweat. And in addition to the worms in your worm bin, microorganisms also live there.
When you feed your worms (and organic matter is mostly made of water), they, along with the microorganisms, break down the food scraps and release water and CO2. This extra water condenses and seeps to the bottom of the bin. So that’s what worm leachate is – the excess water in your worm bin that has seeped to the bottom of the bin.
Having Too Much Worm Leachate in Your Worm Bin Is Not Good
The spigot that lets the worm bin leachate drain is a valuable safety valve. If you leave it open, you’ll know pretty quickly if your worm bin is getting too wet because you’ll see brown liquid seeping out.
It’s important to know if your worm bin gets too wet because the material in an overly wet worm bin tends to get compact and that means air can’t get in. When no air gets in, the material goes “anaerobic” (meaning “without oxygen”).
There are three reasons you don’t want your worm bin to get too wet and go anaerobic:
- Anaerobic decomposition stinks – nobody likes a stinky worm bin.
- Worms need to breathe – anaerobic conditions can kill your worms.
- Anaerobic bacteria are generally bad for your plants.
Since worm seepage only happens when your worm bin is too wet, and overly wet conditions lead to the production of bad bacteria, there is a good chance that the draining liquid will not benefit your plants.
Can You Use Worm Leachate as Fertilizer?
So what do you do with the worm leachate or seepage? If it smells bad, discard it. Pour it onto the driveway, flush it down the toilet, or tip it down the sink, it is not good for plant growth. If the odor is not bad, you can dilute it heavily with water, or run the bubbler in it. However, there is a much better way to make liquid fertilizer for your plants.
Worm castings, because they are filled with the beneficial bacteria from the digestive system of the worm, are great stuff for your plants. You can use them as they are, of course, but you may also decide that you want to use some of the worm castings to create some genuine worm tea.
Make Real Worm Tea
True vermicompost tea is actually cultured or brewed, to help increase the number of good bacteria. Here’s what you’ll need to brew up a batch:
- a handful of worm castings, about a pound;
- 10 gallons of water (if your water is chlorinated, let it sit for 24 hours before using);
- a fine mesh bag or nylon stockings or large sock with no holes and string to hold it closed;
- 1 tbsp organic molasses (or other simple sugar, to feed the microbes)
- a bubbler (the kind used in an aquarium);
- a 5-gallon bucket.
Fill the mesh bag (or stocking/sock substitute) with worm castings and close it up securely. This is the tea bag that you submerge in the 5-gallon bucket of water. Add the molasses and submerge the bubbler.
Let it bubble away for 24 hours, to make sure everything stays aerobic. After 24 hours have passed, remove the bubbler and mesh bag. Dilute the compost tea concentrate with another 5 gallons of water. Use immediately.
You can use the liquid to water special plants or spray it over your entire lawn and garden. (If you use a sprayer, be sure to strain the liquid well so no particles clog the nozzle.) The best time to spray is mid to late afternoon, after the heat of the day has passed.
Your plants will love this genuine worm tea!
Worm Leachate vs. Worm Tea in Short
Worm leachate is the extra water inside your worm bin that seeps to the bottom. It does not go through the digestive tract of worms which has the beneficial microbes that make a good liquid fertilizer. It is rarely good for your plants and can actually be harmful. If your bin regularly has a lot of worm seepage, the conditions are likely too wet.
Worm tea is made from worm castings. This is the good stuff that you want to use to fertilize your plants!