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How are Worm Tea and Worm Leachate Different?

spigotOne 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 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.

The spigot that lets the worm 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, and
  • 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.

What to Do With Extra Liquid

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. If the odor is not bad, you can dilute it heavily with water, or run the bubbler in it (see below). 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 worm 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:

  • worm castings, about a pound
  • 10 gallons 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), and
  • a 5-gallon bucket.

Fill the mesh bag (or stocking/sock substitute) with worm castings and close it up securely. This is your 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 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!

17 comments on “How are Worm Tea and Worm Leachate Different?

  • Marta Krissovich says:

    My standard compost bin regularly needs water to maintain the correct moisture balance. Can I use worm leachate instead of water for this?

  • I have had my worm for now for about a year but am still not the most educated on them. I have been using the leachate on my house plants and they have been thriving. I get about a cup per week and dilute it with water. Does this sound like my worm been is overly moist? I have not had any problems with stink or bugs, but do have some brown mites (which I read were okay in small doses). I would love to start a home worm farm for some extra money while I finish school, but need to learn more I guess!

  • @sarah: The article states the leachate may be used to moisten the new dry bedding, which was suggested as a solution for too-wet bin. Most experts advise discarding the leachate, away from plants for safety’s sake (flush it down the toilet!) IMHO, if the bin is too wet, add more dry bedding (coir fiber or just torn up newspaper), and let the worms do the rest. If it’s too dry, toss in a chopped up ripe canteloupe and you’re golden.

    The whole point of the worm bin is the worm castings! Use them up on your veggies, and flowers. I think a too-big bin could also be a culprit when it comes to the material staying wet. I’ve read other articles that say a healthy bin doesn’t really drain because the ratio of worms to veg matter to worm castings, when exactly right, it remains moist but not overly so. Above all, I would NOT use the leachate (runoff from rotting veg, pathogenic, could actually kill the beneficial microbes we are trying to promote!) for anything, most especially consumable garden produce. Organic farmers and gardeners wouldn’t even put non-edible trimmings in the regular compost heap if they had been treated with the leachate.

    There are plenty of items on the innerwebs on how to “make” worm compost tea. Compost Tea isn’t a byproduct of worm farming! You have to make it!! And plants love it. (Plants grow like crazy if we use sewage based “sludge”, but we now know that’s a very unhealthy practice. So, just because we get great results doesnt mean it isn’t dangerous.)

    Happy Gardening!

  • I am a new vermicomposter.

    I have the plastic stackable bins with a reservoir for leachate. I noticed that when I check the leachate reservoir, I find handfuls and handfuls of worms.

    What does this mean? Are the worms able to move back into the top bin on their own?
    Are my conditions perhaps not right? Or are they simply looking for a cool and moist spot?
    Im southern California, and we just got hit with a heatwave.

  • @Michael
    I’m in Vista, CA and have a bin for 2 yrs. The heat down here will kill these guys quick if you don’t regulate the temp. They truly start melting when it’s over 90 degrees F. They are trying to escape the bin and find cooler places to survive. A closed-in SoCal garage is no sanctuary!
    I freeze a few 2-liter bottles full of water and put one frozen in the top most bin in the mornings when the forecast is going to be hot. It drips cool condensation throughout the day and keeps the temperature inside near 70 all the time.
    There’s a spigot on the bottom always open and all excess moisture drains away.
    A few worms, mostly dead ones, are coming through the spigot. I dump them all out into the edge of our yard once a week or so. The yard doesn’t seem to mind the extra few worm or water.
    The worms have been happy since I started doing this.
    All the best.

  • I started my worm bin about 3 months ago and all seems to be going very well. The leachate its producing is a pale yellow and has no odor at all. is this uncommon as I’ve only read leachate described as dark brown. The bin itself has a nice earthy smell, nothing offensive. I check it daily and pour the leachate onto my outdoor compost.

  • I am about a year in and stated with 1 single layer rubbermaid bin and have split a couple times and this week started my 3 multi layer bin. I drain about a gallon of very dark leachate every week or 2 and it does not have an odor at all, and there are usually 30-100 worms that I pick out and throw back into the bin.
    I used to dilute the leachate and feed to my house plants until figured out that was not vermipost. the plant did like it but once i started brewing tea I think they really thrive on it. Spring if here and snow is melting so I am excited to start feeding my garden. I think I will dilute the leachate and feed trees with it as I feel there are beneficial microbes and nutrients in it, especially if its fresh and not anerobic.
    My long winded question, does anyone move their worms outside for the summer and take them in for winter? I was going to build a large compost heap with my current outdoor compost and add a few pounds of worms. Will the heat of the compost heap kill the worms?

  • A hot compost pile will cook worms. They’ll sorta move the perimeter of the pile to avoid the heat if they can. Best to add them to a compost pile after the thermophilic process has finished. I let my outdoor compost piles cure for about a month after they finish cooking, and that’s when i mix in a few scoops from my worm bins.

    I just did this with a compost pile a few days ago. It was still a little warm to the touch when I flipped it but it looked pretty well decomposed, so a couple of scoops from my worm bins got mixed in. I’ll let that pile sit for about a month, flip it maybe once during that time, then use it in the garden/lawn.

  • I am so excited to find this page. I do not fertilize my yard with chemicals simply to keep our family and the environment safe. I always just toss casting over the grass and plants. I can’t wait to make the tea and feed the yard. Thanks for sharing!

  • I scooped out my leachate and I realized there are these really really tiny white (maybe greenish?) bugs congregating on the top of the liquid. They’re too small to really describe well but there are a lot of them and they are capable of hopping around the top of the liquid. Are these normal or safe? Should I be concerned?

  • When making worm tea, can I add some of the seepage to the mix to help get it healthy? Using a bubbler too of course…

  • I note that the descriptions for your worm farms describe the leachate as worm tea….
    Valuable “Worm Tea” works its way down to the collector tray where you can utilize the handy tap to dispense the tea and use it as liquid organic fertilizer for all your plants.

    Perhaps you should rewrite this ?
    But apart from this, a very informative website, thank you !

  • I’ve seen different recommendations on watering a worm bin. Some posts suggest there should be little leachate. Instructions for my Worm Cafe recommend watering the bin once a week with at least 5 gallons of water, which produces lots of leachate as one would expect (and which I then dilute and use to water plants). Is this just different schools of thought? Does watering help keep the bin cooler?

  • Correction on my above question — 5 liters of water, not 5 gallons (not creating a worm swimming pool).


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