How To Make Worm Casting Tea

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This article provides instructions for making worm casting tea you can use to feed all types of plants
by Brett · All Zones · Fertilizing · 1 Comments · May 10, 2012 · 4,932 views

What you'll need to make worm castings tea:

  • 2 cups of well composted worm castings (no large scraps, preferably sifted)
  • 2 tablespoons of corn syrup or molasses
  • Water which has been left to stand overnight or rain water.

Step-By-Step Instructions

  1. Fill a bucket with water. Either use rain water or let the water stand so the chlorine can evaporate out. You don't want to kill the beneficial micro-organisms, which is what chlorine-treated will do. Using a bubbler will speed up the release of Cl- ions from the water, cutting down the time the water needs to stand.
  2. Add the corn syrup or molasses to the water. This will serve as food for the micro-organisms. It helps to dissolve the molasses in a small volume (like half a cup) of hot water before adding it to the bucket. This prevents potential obstruction of your air bubblers.
  3. Place castings in the bucket by either putting the castings into a thin mesh "teabag" of pantyhose or a similarly sheer sock and knotting the end. The knotted end of the bag can be hung down and submerged so the tea bag is situated above the rising bubbles. Some simply dump the teabag in. putting the castings in directly if you plan to use a watering can anyway, otherwise, straining through cheesecloth or mesh may be necessary when using backpack-type sprayer with nozzles that could clog easily with debris.
  4. Realize the grade or particle sizes of your choice of castings (determined by source and packaging process) play a role in making this choice. Casting particles in sizes larger than marbles, or even bark mulch. Other's are finely ground castings, smaller than ball bearings. The difference in total surface area exposed to water is much larger for the finely ground which has more exposure to the aerated water.
  5. Put the worm castings in directly into the bucket. Some people say put the castings in an old sock or stocking hose that has no holes and tie the opening closed. This does not allow the castings to exchange into the water freely and slows the growth of the micro critters. Both ways give satisfactory results with the castings right in the water. Also, slime mould formations which are micro critter super colonies, may form. This shows the intense populations of tea made this way. You can use a plastic watering can without the strainer on the end and apply the tea in total - castings and all.
  6. Use a bubbler like an aquarium pump and airstone if you have one. Place it in the the bucket and hold the air stone to the bottom with a rock. Plug in the bubbler so the the water is aerated.
  7. Let water and castings bubble (or at least soak) for 24 hours. If you don't have a bubbler, consider stirring occasionally- don't worry you cannot hurt the micro critters (microbes) by stirring. The air stone at the bottom of the bucket will cause the tea to be in constant mix - this is the best way to get a high yield tea.
  8. To produce high yield tea, conditions should be desirable for the microbes to proliferate, multiplying exponentially. The microorganisms from the digestive system of the worm are extruded in their castings. These aerobic (oxygen-dependent) microbes are "good" microbes for plants (nature's way). Bad microbes are typically anaerobic (oxygen kills them) and many give off offensive odors as they release byproducts of metabolism like hydrogen sulfide (rotten egg smell). Aerating the tea improves conditions (agitation, circulation, aeration) for the good microbes, which enhance (survival, reproduction, growth). Aeration helps suppress the presence or growth of bad "bugs" that will compete against the good ones. Use of a bubbler helps along dissolution of the molasses food as well; it dissolves and diffuses more rapidly. Some instructions for tea setups without a bubbler recommend up to three days of brewing.
  9. Use within 48 hours. Exponential populations in limited spaces eventually peak and then plunge with massive population loss. We want the tea to be biologically active, alive, with good microbes like Bacillus subtilis.
  10. Refrigerate (in a sealed, labeled container) for up to 3 days. Non-pleasing odors from the tea after initial brewing or prolonged refrigeration may signal a low quality brew which should probably be dumped. This could be added to a composter or wormery to prevent waste.

If you are interested in trying earthworm castings you can find this amazing fertilizer at

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Troy Meyers

Troy Meyers · Gardenality Stem · Zone 6B · -5° to 0° F
I have a small vermicomposter I keep in my house. The problem for me has been getting enough of it. I will try this method to get some more. Giving some worm team to flowering plants seems to make them flower even more.

9 years ago ·
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