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What Is Worm Tea?
Worm tea is a natural liquid fertilizer made from soaking worm castings (worm manure) in water. In a healthy compost bin, worms help decompose food scraps by eating them. As the worms digest the organic material, they produce castings filled with nutrients and beneficial microbes. Steeping these castings in water overnight creates a worm tea that helps boost plant growth.
Worm casting tea should not be confused with worm leachate—the drainage liquid that collects at the bottom of your worm bin. Leachate can be harmful to certain plants.
How to Make Worm Tea in 5 Steps
Brewing a high-quality batch of worm tea is an easy, straightforward process.
- Gather your materials. To make worm tea, you’ll need a compost tea bag (this can be any porous, natural fiber bag), a five-gallon bucket of dechlorinated water (e.g. distilled water or rainwater), and worm castings (should fill about a tenth of the bucket). To collect the worm casings, purchase a worm bin, fill it with a mix of soil and kitchen scraps, and add red wiggler worms—the worms produce castings as they eat the kitchen scraps.
- Fill the bag with worm castings. Fill your porous worm tea bag with your vermicompost (the worm casings), and tie the open end of the bag shut.
- Steep the bag in a bucket of water. Begin the steeping process by submerging the teabag in the bucket of water. Aeration boosts microbial activity, so you may want to use a fish tank bubbler to add extra oxygen to your worm tea.
- Keep the bag submerged overnight. You'll know your worm tea is ready to use when the water is light brown.
- Dilute the tea with water. Remove both the fish tank bubbler (if necessary) and the teabag from the bucket. Dilute the tea with an additional five gallons of water; the tea won’t lose its potency and will last longer.
How to Use Worm Tea to Fertilize Your Garden
Once you’ve brewed worm tea, use it as soon as possible. Water your plants with worm tea every two weeks, or once a week for fruits and vegetables.
- Choose your delivery method. A watering can or spray bottle are acceptable options. If using a sprayer, strain the worm tea to avoid clogging the spraying mechanism.
- Water your plants with worm tea. You can water your both your outdoor garden plants and your houseplants with worm tea. Make sure to cover both the soil and the plants' leaves. In addition to fertilizing the soil, the microbes in the tea help stave off plant disease.
- Properly store any leftover tea. It’s important to store any remaining tea in a container without a lid so the good microorganisms can receive enough oxygen to survive. The microorganisms in the tea die over time and the tea becomes less effective. For best results, use a new batch of tea every time.
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