Worm Castings: Uses | Benefits | Tea | Organic Solutions

Most gardeners want organic natural fertilizer for plants, and there are lots of choices. 

Worms are good for stirring up soil and keeping it aerated. But, using earthworm castings as fertilizer is a great way to allow plants to flourish!

Vermicompost fertilizer for planting trees, The man's hand is showing organic fertilizer make with earthworm, earthworm in hand
Earthworm casting mixed with coffee grounds has many benefits for plant growth | pimnana-DepositPhotos

What Are Worm Castings?

Organic worm castings are dried worm manure aka worm poo. Unlike animal manure, earthworm castings don’t smell, and they aren’t harmful to use as fertilizer. 

Animal manure can contain harmful bacteria from the food they consume. The waste needs treatment before use as compost.

As red wiggler worms aerate the soil, they also eat natural material and tiny organisms. This material gets ground up in their digestive system, and they release the organic material back into the ground. 

Their waste is organic matter full of minerals that work as a soil conditioner and help plants grow, providing calcium, nitrogen, and potassium.

A benefit of using earthworm castings is that they have other trace elements beneficial to plants. Since the castings are an organic substance, your plants immediately benefit from the nutrients.

Otherwise, the plant would need to break down organic matter themselves, as many composts and fertilizers make them do.

Benefits of Worm Castings

Worm castings contain natural growth hormones to boost plant growth.

In addition to minerals plants need like:

  • Calcium
  • Nitrogen
  • Potassium
  • Phosphorus

Earthworm castings also contain humic acid. This acid loosens the soil (soil aeration) so plants can access even more nutrients.

Elements like humic acid help strengthen a plants’ roots and help protect them from root diseases such as root rot and predators.

When planting in soil using worm castings helps prevent plants from absorbing dangerous chemicals leaching into the ground. 

They can also help balance soil pH levels so plants can grow without hindrance. A tablespoon of pure worm castings is enough to feed a small plant for two months!

How To Get Worm Castings

The building or investing in a worm farm allows you to harvest worm castings at home. Keep a shallow box layered with sand, compost, and leaves moist for worms to tunnel in. 

Harvest castings every two to four months. Worm castings are also available to purchase. Look for a product that is 100% castings with no filler.

Using Worm Castings for Planting

If you’re starting with seedlings, mix:

  • One cup of worm castings
  • One cup of potting soil 

This mix is a slow soil enricher, giving seedlings a healthy start.

When transferring plants to the garden, add a quarter cup of earthworm castings into the fresh hole.

Organic worm castings also work in hanging plants. As you prepare to pot plants in a hanging basket, add half a cup of castings to the soil. 

If you’ve bought a hanging plant and want to add worm castings, sprinkle it on top of the potting soil so the nutrients will work their way in as you water the plants.

Sprinkle castings around the garden. Since worm castings are entirely organic, there is no need to worry about contaminating edible plants. 

Rain and regular watering will naturally cause the castings to break down. They will slowly release plant nutrients in the soil, like a natural timed-release fertilizer! 

Sprinkle worm castings around the vegetable garden, use worm casting as a side dressing, and in container plants every month, so they continue to get organic plant food.

Use worm casting for fertilizing succulents, as a natural rose fertilizer, and in growing Oriental lilies.

Making Liquid Fertilizer – Worm Casting Tea

If you love how worm castings boost your garden’s soil, you will be happy to know that castings can make a liquid water-soluble fertilizer! 

A benefit to liquid fertilizer is that you can spray it on the plant. This lets the plant take in mineral nutrients through their leaves, instead of only through their roots. 

When worm casting soaks in water, it creates what gardeners call “worm casting tea.” 

How To Make Worm Casting Tea

  • Soak ¾ of a cup of worm castings in one or two gallons of water
  • Let it steep (hence “tea”) for at least a day
  • Strain the castings out of the water 
  • Pour the liquid into a spray bottle

Spray this solution on your plants every week or two to ensure they are getting all the nutrients they need.

It’s true – there is a usable type of natural fertilizer that is organic and completely healthy for the plants and people!

More on Making Garden Teas

Give worm castings a try, or try raising your own. See how they boost your garden.

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