How to make worm casting tea?

Worm casting tea isn’t a trendy new health drink for you – it’s actually for your plants. You can create a non-toxic organic fertilizer using worm castings that will enhance soil and improve the growth of your indoor and outdoor plants. 

While you can purchase this tea readymade, it’s easy to make on your own. Read on, and we’ll tell you exactly how.

What is Worm Casting Tea?

The fancy term for worm tea is vermicompost tea. Vermi means worms. So vermicomposting is simply the process of using worms to make compost. 

Worm tea is a natural solution that will improve the diversity of plant soil, repel pests, and prevent plant disease.

Composting is a win-win for your garden and the planet. While disposing of food scraps and reducing landfill waste, you can also create organic fertilizer for your plants full of beneficial microbes. 

Here’s how worm composting produces castings:

When worms consume organic matter, and it passes through their system, their bodies infuse it with good bacteria. Once excreted, this matter is now known as worm castings.

Castings are more than just worm poop. Compared to regular soil, worm castings can contain:

  • 5x as much nitrogen
  • 7x as much phosphorus
  • 11x as much potassium

Soaking the castings in water overnight produces the nutritious solution known as worm castings tea. 

Perhaps you already have a compost pile. Maintaining a worm farm is a simple additional step that will help you dispose of your compost while creating earthworm castings that you can ultimately use for various plants. 

How to Make Worm Casting Tea

Before making worm compost tea, you first have to gather some castings. You can purchase castings and readymade tea online or at some local gardening stores. Vermisterra earthworm castings and Vermisterra earthworm casting tea are two great options. 

However, you can also make worm casting tea yourself. Wait, before you send the neighborhood kids out to gather random worms off the sidewalk, make sure you’re collecting the right kind of worm. For vermicompost, use Eisenia foetida worms, commonly known as “red wigglers”.

There are worm bins specifically designed to cultivate worm compost, or you can make your own out of a plastic bin or Rubbermaid container. Select a shallow bin and drill holes in the top and bottom. Airflow is essential to cultivate the growth of good bacteria.

To create your worm bin, alternate layers of the following compostable materials within the container:

  • Shredded cardboard
  • Kitchen scraps (coffee grounds, used tea leaves, produce peels, etc.)
  • Organic matter (twigs, leaves, mulch, ground limestone, used potting soil, etc.)

Put your red wiggler worms on top, cover the bin, and leave them alone for one week so they can start the composting process.

Make sure the compost stays moist but not overly wet, which could cause harmful bacteria to grow. Then, add compost food for your worms to eat each week, slipping it under the cardboard.

You’ll also want to place an empty container below the bin to catch the castings as they drop through the bottom holes.

Now let’s move on to making the compost tea.

Materials and Supplies 

You’ll need the following supplies to start your compost tea: 

  • Five-gallon bucket
  • Dechlorinated water (distilled or rainwater)
  • Worm castings 
  • Porous material, bag, or stocking to use as a “teabag”
  • Fish tank bubbler (optional but recommended)
  • 1-2 tablespoons molasses or sugar (optional)

Now you’re ready to start the process! 

How to Do It 

it’s time to make the tea. Follow the following instructions to get the best results. 

  • Place your worm castings in the tea bag material, and tie them off. You will need a few scoops of castings or enough to fill the bucket approximately one-tenth of the way full. 
  • Next, fill the bucket with water. Be sure to use a form of dechlorinated water such as distilled water or rainwater. 
  • Place a fish tank bubbler in the bucket as the tea is steeping to aerate your tea. Aerated compost tea contains an even higher density of beneficial microbes. 
  • Add a small amount of sugar. One to two tablespoons will suffice and will also enhance beneficial bacteria growth.

Let the tea steep (soak) overnight. When ready, the tea will be a light brown color. 


Some of our recommendations include:

Find products that compare to the above to get the most out of your worm tea experience. 

How to Use Worm Casting Tea 

Before applying it to your plants, dilute the castings tea with an additional five gallons of water. It should still be a light brown color after dilution.

Strain the castings tea and pour it into a spray bottle or watering can to water your plants. 

Worm tea is beneficial for both indoor and outdoor plants. 

We recommend spraying both the soil and the leaves, as this will more effectively disperse the healthy bacteria over the plant. Covering the leaves is helpful because the microbes in castings tea may also minimize plant disease.

You can store the tea solution for 48-72 hours unrefrigerated and up to 30 days if it’s kept refrigerated. Leave the storage container open or loosely covered because the microorganisms will die off without air. 

Be aware that composting tea can go bad. It should smell earthy, but if the tea smells rancid or foul, discard it.

Although you can store the tea for short periods, many experts recommend using a fresh batch for each watering. 


Here are some of the most commonly asked questions about worm casting tea and their responses. 

Is worm casting tea good for plants?

Yes, worm casting tea provides beneficial bacteria to your plants that will promote growth and yield. In other cases, research experiments have shown improvement in crop quality when plants are watered with worm tea.

How often can you use worm tea on plants?

Water your plants with worm tea every two weeks. For fruits and vegetables, you can water with the tea once a week. In addition, you can spray worm castings tea on your lawn up to twice a week.

Is worm tea better than worm castings? 

Although some gardeners apply worm castings directly to the soil, the castings have fewer beneficial microbes compared to worm tea. Steeping the castings in water, especially when using aeration, encourages the growth of that bacteria.  

Can I make worm tea from worm castings? 

You can make worm tea with worm castings by combining water and castings to create the tea. 

How long can you brew worm casting tea? 

Your worm tea should be ready after soaking overnight, or you can brew it for up to 24 hours. 

Does worm casting tea need to be diluted? 

Yes, worm casting tea needs to be diluted. Although worm tea won’t burn plants like chemical fertilizers, you should dilute it and then distribute the mix on the same schedule you typically water.

Does worm tea really work? 

Research studies have shown that aerated vermicompost teas promote germination growth, flowering, and yields. These results have been demonstrated in a variety of fruits and vegetables. 

What is the difference between worm juice and worm tea? 

When you maintain a worm farm, a liquid waste will seep out of the bottom. This drainage is called worm juice or worm leachate and isn’t the same as worm tea. 

Worm leachate occurs when the worm bin has too much moisture and produces bad bacteria – this is the opposite of worm tea which contains good bacteria for your plants.

So how can you help your garden grow? One solution might be worm castings tea. 

With a bit of time and effort, you can maintain a worm farm, utilize your compost, and transform their waste into food for your plants. 

It’s a beneficial process on all ends, and the outcome is healthier plants with less disease and pests. 


Download Your Free eBook: The Ultimate Guide to Compost at Home

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