How to Use Worm Castings in Potted Plants: Create a Thriving Indoor Plant Collection

We have to admit, we weren’t expecting this one ingredient to transform our plant parent journey. Incorporating worm castings into our plant maintenance routine elevated our houseplant collection to a new level. No wonder they call it BLACK GOLD!

And the great thing is you can incorporate these worm castings into your routine in multiple ways.

So, if you’re not already excited about worm castings, by the end of this guide, our mission is to get you so excited that you will be running out the door to grab a bag at your local nursery!

How to Use Worm Castings in Potted Plants

How To Use Worm Castings In Potted Plants

On initial impression, you may think it is overkill, dedicating an entire guide to How to Use Worm Castings in Potted Plants.

You add it to your plants, and you’re done, right?

Well…not exactly

Joey surprise gif

We’ve got good news! There are many different applications for how to use worm castings in potted plants.

We will explore (in detail) all the methods you can use for worm castings to keep your indoor plants happy and healthy.

Using Worm Castings in Your Potting Mix

As we subtly hinted earlier, one of the more common ways of using worm castings for potted plants is to mix it into your potting mix.

And, we agree, it is one of the most effective ways to deliver this nutrient-rich ingredient directly to the root system of your houseplants.

In fact, worm castings are one of the core ingredients in our potting mixes, and we make sure we always have some on hand whenever we repot our houseplants.

Check out how we incorporate worm castings into our favorite Monstera potting mixture:

Here’s a quick guide for how to incorporate worm castings in your soil mixes when repotting your plants:

  1. Remove the plant from its current pot and gently shake off excess soil.
  2. Create a new potting mix using a blend of two parts regular potting mix, one part worm castings, and one part organic compost.
  3. Fill the new pot about 1/3 full with the potting mix, and place the plant in the center of the pot.
  4. Backfill the gaps on the sides with more potting mixture, ensure the plant is securely held, and water thoroughly. Make sure any excess water drains freely from the drainage holes.

Garden Bench Top TIP

Up your plant parent skill and increase your PLANT AWARENESS by researching the soil composition your plants require. Then, supercharge your mixture by substituting some worm castings for regular potting mix.

Using Worm Castings as Top Dressing

worms and worm castings for potted plants

Another popular method for applying worm castings to your indoor plants is as a top dressing.

This method is handy for already established potted plants or when plants are less active and lying dormant in winter.

Worm castings are also a mild form of fertilizer, so using it instead of commercially manufactured fertilizers will avoid any risk of fertilizer burn.

To use worm castings as a top dressing, all you need to do is:

  1. Liberally sprinkle 1 to 3 tablespoons of worm castings around the stem of our container plants and then water well.

This helps improve soil aeration and nourishes our potted plants throughout the growing season.

It will also boost the organic composition of your potting mixture and naturally fertilize your plant each time you water it, which is one of the many benefits of using worm castings.

Using Worm Castings to Make Worm Tea for Potted Plants

Another fantastic way to reap the benefits of worm castings for our potted plants is by making worm tea.

If you are not familiar with worm tea, don’t worry. It is better than it sounds. We will not be steeping any worms today!

tea is served

In short, worm tea is a liquid fertilizer that contains nutrients and beneficial bacteria from the worm castings.

In other words, it is liquid gold and can be absorbed quickly and efficiently by our indoor plants.

Here’s an easy way to make worm tea:

  1. Add one cup of worm castings to a 5-gallon bucket of water.
  2. Stir the mixture well and let it sit for 24 to 48 hours, stirring occasionally.
  3. Strain the mixture through a mesh or cheesecloth to remove the castings, retaining the liquid.
  4. Dilute the worm tea with water, using a 1:10 ratio of worm tea to filtered water.

For a full rundown of worm tea, check out this article HERE.

Now we have our worm tea, it’s time to feed our plants.

Simply water your potted plants with the diluted worm tea.

Benefits of Worm Castings in Indoor Pot Plants

worm castings on spade

Worm castings are an excellent addition to indoor plant care because they are nutrient-rich, eco-friendly, and cost-effective. Here are the key benefits of using worm castings:

  • Nutrient-Rich Plant Food: Worms break down organic matter into a form easily absorbed by plant roots, providing essential nutrients such as magnesium, zinc, copper, and beneficial microbes.
  • Safer Than Chemical Fertilizer and Animal Manure: Unlike these alternatives, worm castings are eco-friendly, odorless, and pose no risk to our environment or homes.
  • Enhanced Water Retention: The porous texture of worm castings increases the soil’s ability to hold water, reducing watering frequency and ensuring plants stay hydrated longer.
  • Natural Pest Resistance: The beneficial microbes in worm castings boost plants’ immune systems, increasing their resistance to diseases and pests without harmful chemical pesticides.
  • Cost-Effective (Worm It Yourself!): Making worm castings at home through vermicomposting reduces the need for purchased fertilizers, saving money and promoting sustainability.

This is just a brief glimpse into the benefits of worm castings. If you want to learn more about how they can elevate your indoor plant care, check out our in-depth article on the topic – click here to read more.

Worm Castings: A Game-Changer for Container Gardening

Did you know worm castings are not only limited to indoor plants? In fact, container gardening can also reap the benefits of this organic soil amendment.

Benefits of Worm Castings in Container Gardening

Container plants are particularly suited to benefit from worm castings. Here’s why:

  • Nutrient-rich: Worm castings are packed with minerals essential for plant growth, such as concentrated nitrates, phosphorus, magnesium, potassium, and calcium.
  • Improved Soil Structure: Worm castings enhance the soil structure. They increase their capacity to retain water and thus reduce the watering needs of your container plants.
  • Boost Plant Immunity: They help boost the plant’s immunity against diseases and pests. Hence, your container plants will be healthier and more resilient.
  • Eco-Friendly: Worm castings are entirely organic and sustainable. They don’t contain harmful chemicals, making them safe for your plants and the environment.

Adjusting Application of Worm Castings: Indoor vs. Outdoor

While worm castings benefit indoor and outdoor container plants, the application may need to be adjusted according to the specific plant needs and environmental conditions.

Indoor Plants

For indoor plants, a little goes a long way. As a rule of thumb, you can add worm castings to your potting soil mix at a ratio of 1:4 (1 part worm castings to 4 parts soil). It’s recommended to refresh the mixture every time you repot your plant or about once a year.

Outdoor Container Plants

Outdoor container plants typically need more nutrients than indoor ones due to exposure to weather elements and faster growth rates.

Therefore, you should use a slightly higher ratio of worm castings for these plants, say 1:3 (1 part worm castings to 3 parts soil).

We also recommend using the top-dressing applications with worm castings every few months to supply the plants with the necessary nutrients.

Frequently Asked Questions for How to Use Worm Castings in Potted Plants

Can You Use Only Worm Casting as Soil?

Absolutely, you can use worm castings as soil! However, mixing them with your existing soil or potting mix is generally better. This is because worm castings are incredibly rich in nutrients but don’t provide the best drainage and aeration for plant roots. So, a 1:1 or 1:3 ratio of worm castings to soil would be a good start.

Does Worm Casting Burn Plants?

No, worm casting won’t burn your plants. It’s actually one of the gentlest plant foods out there. Worm castings slowly release nutrients, providing a steady supply without the risk of overloading your plants. So, go ahead and feed your plants without fear!

How Much Worm Casting to Add? How? How Often?

As for how much to use, a good rule of thumb is to add about 1 inch of worm castings to the top of the soil. If you’re potting a new plant, mix worm castings with the soil at a ratio of about 1:3 or 1:4.

When adding worm castings, you can mix them into the soil, or if you don’t want to disturb the roots, simply add an inch layer on top of the soil.

As for how often, it’s usually enough to add worm castings once every 2-3 months. But remember, every plant is unique and may have different needs. Pay attention to how your plant responds and adjust as necessary.