Worm Casting Tea: Everything You Need to Know

by Sam Richards | Last Updated: November 18, 2020

Fertilizers are important for keeping plants healthy. They replace the nutrients that are no longer present in the soil. It supplements the necessary minerals for healthier growth. However, fertilizers can also contaminate the water supply, especially those with phosphates and nitrates. A lot have harsh chemicals that can pose more risks than benefits.

If you are looking for natural fertilizer, you can’t go wrong with worm tea! It is a by-product of vermicomposting, allowing you to harvest a nutritious compost out of healthy worms. It is worm poop loaded with the essential minerals that plants need. Keep on reading to know more about what it is and how to prepare one.

What is a Worm Tea?

Some might take it too literally and think of it as a tea made of worms. Technically speaking, however, it is a tea that comes with worm castings. In case you do not know, casting is an organic fertilizer from earthworms. Also called vermicast, it is an earthworm waste. Worms are taken care of in a container where there is also bedding and the worms are fed organic scraps. As they mature, they release castings, and this is what is used for making a tea that is in turn fed to plants.

The mineral composition of vermicast tea will differ depending on the source. It is commercially available and manufacturers may have different formulas. If you are making one at home, the composition will differ based on what you are feeding worms. It contains up to 30% organic carbon. In small quantities, there are also nitrogen, phosphorus, potassium, nitrogen carbon, calcium, and magnesium, among others.

Perhaps, the most important thing to note is that while it is called a tea, this isn’t a replacement for the tea that you are drinking at home. It is not fit for human consumption! Even if you like to eat and drink anything exotic, worm compost tea should not be one of them! It is made from a by-product of worm poo and household waste. Although it is organic, it is not for humans.

How to Make Worm Casting Tea?

It can be quite intimidating for beginners, but the process is pretty much straightforward. Even if it is your first time doing so, things don’t have to be complicated. While it requires minimal effort, making worm cast tea is a rewarding experience.

Here’s a quick step-by-step guide on how you can make a vermicast tea. There are different variations, so feel free to do as you please. The assumption in this recipe is that the castings are ready. This means that they have already been harvested, so your main focus is on making the tea itself.

  1. Look for a five-gallon container and add water. It is best if you can use rainwater. Otherwise, you can use tap water but give it enough time so that chlorine will evaporate. A bubbler can also be helpful. Having chlorine is a bad thing because it might kill the beneficial microbes in your compost tea.
  2. Add molasses or corn syrup. Start by dissolving the latter in hot water before pouring in the gallon. This is an important step because it will serve as food for the microorganisms.
  3. Add the castings to the bucket. When doing this, you have two options. The first is to use a pantyhose or similar material that can also function as a mesh tea bag. Add the castings on the makeshift teabag, tie the open end, and let it hang, making sure that the castings are submerged in the water. The second is to add the castings directly in the bucket, eliminating the need for a teabag.
  4. Leave the castings for up to 24 hours. This will let the water absorb everything from the casting. You can also install a bubbler. Otherwise, you can give the water a quick stir.
  5. You can now use the tea after steeping. It is best to use it as soon as it is steeped. Nonetheless, if there is any unused portion, don’t throw it! Seal the container and refrigerate to prolong its functional life. Make sure to add a label to the container! Someone in your home might end up drinking it!

If you need the fertilizer tea only in small doses, there is an easier way to make one. All that you need is a paper coffee filter. Add ¼ cup of the worm castings and tie the open end. Once it is closed, add to hot water just like how you would normally steep tea. After about three to five minutes, the tea is ready and you can give it to your plants. This is a good way to avoid waste since you are making the fertilizer in a limited quantity.

How to Use Worm Tea?

Now that you know how to make a worm casting tea, it is time to use it in your garden and enjoy its many benefits. Here’s a quick guide on how to use the tea on your plants:

  1. After steeping the tea, transfer it to a spray bottle, which will make its application a lot easier. Strain the tea first using cheesecloth or similar material. This will get rid of the chunky particles, which can clog the spray and limit its functionality.
  2. Once the tea is in the sprayer, apply it directly to the plant you would like to fertilize. Start on the soil, making sure that you spray enough but do not saturate. If you spray too much, the soil will be soggy. This can encourage the presence of diseases. Also, spray on the leaves.
  3. After watering your plants, store the leftover tea. Keep it sealed to preserve freshness and maximize its benefits. As mentioned earlier, it is best to refrigerate the tea while making sure that it has a tight seal.

As you use worm fertilizer tea, another important consideration is the proper timing, which will maximize the results. We suggest that you do it during the active growing season. It will depend on your location and the plants that you are growing. For houseplants, you can give them the tea once every ten days. On the other hand, for outdoor vegetables, add the fertilizer at least once a week. The good thing is that you cannot overdo it, but the most important concern is to prevent saturating the soil.


Not convinced to give your plants worm water? Here are some of the compelling benefits that might make you change your mind:


In sum, a worm casting tea is an easy recipe for DIY fertilizer. It uses the by-product of your vermicompost. The vermicast in the tea is loaded with minerals that ensure the healthy growth of plants. This is not only a good way to enjoy a natural fertilizer in your garden, but this is also a practical solution for household waste management. You don’t have to think about the disposal of your organic scraps. You can add them to the worm bin, and when the time comes, it will produce castings that you can use as a fertilizer tea.

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Types of Nightcrawler Worms: How to Identify Them

How to Make a Worm Farm for Fishing