Castings  & Compost Tea

World of Worms being sorted in Kelowna BC


Castings are the product of worm composting. Also known as vermicast, vermicompost, worm castings, worm humus or worm manure, it is the end-product of the breakdown of organic matter by species of earthworm. The worms, usually red wigglers and other composting worms, create a heterogeneous mixture of decomposing vegetable, or food waste, and bedding materials. Containing water-soluble nutrients, castings are a nutrient-rich organic fertilizer and soil conditioner with around 10 times more nutrients than outdoor compost.

Castings do a lot more than chemical fertilizer as the microscopic organisms in the compost maintain the ground soil in good health condition. The worm compost is rich in excellent nutrition for your garden and your plants (microbes, humus and enzymes). The compost texture is also helpful for soil regenerations because it can hold up to 3 times its weight in water. Because of the coding effect, which happens during the digestion by the worms, the vermicompost will slowly release its nutrients once mixed in the soil.

Regeneration of soil:
Castings can be used for ground soil regeneration. Ground soil can be improved with natural fertilizer and organic matter. Your production of castings will increase the growth of your plants in your garden and make your indoor plants look healthier.

When we look at the bigger picture, the best news of all is the fact that the vermicast or castings are regenerating our topsoil. We are now creating instead of eroding the topsoil of our planet. Did you know that according to different sources, the topsoil of our planet is being eroded 10-40 times faster than it is being replenished? In 2010, we lost 87 million tonnes of topsoil. The lack of topsoil is the reason why nothing grows in deserts.
Instead of throwing valuable resources in our landfills, we can simply compost with worms to recreate the few inches of topsoil that are essential to our lives on this planet.

Have a look at these tests on castings with different seeds. The results are interesting.

Eco Yard Farming

Vermiculture Canada

This is exactly what you can do at home… on a smaller scale!

Compost tea

Making compost tea is a great way to extend the quantity of compost or castings, because you just need a small quantity of compost. Anybody that has used compost tea will tell you how well it works. You can use it on all types of plants, as a spray or just as a liquid that you would use to water your plants.

During the process of making compost tea, it is crucial to use oxygen for all the microbes to survive (as seen on the previous video). Therefore, it is impossible to bottle it. You must use it immediately after making it, in the anaerobic stage, before it loses all of its oxygen and starts to smell.

Here is a video showing an easy way to make vermicompost tea.


  • Used on the roots of plants, it will nourish the plant as well as keep the right humidity for the roots. You will definitely see a difference on the root system of your plants… Sprinkle up to 1/4 inch of castings in the hole before planting flowers, trees, shrubs and even in your vegetable garden.
  • Used to top-dress your loam, vegetable garden, it will provide high level of nutrients and retain water for overall better health of your plants… For 1000 square feet, equally sprinkle 50L of castings.
  • Used for indoor plants, the vermicompost is also a good fertilizer… Put ¼ inch of vermicast on the top of the soil of your indoor plants every time you want to fertilize them. The nutrients will then be delivered every time you water your plants.
  • Used as Liquid Fertilizer, the liquid that you harvest from the spout is called leachate and not compost tea. It can also be used as fertilizer for your plants. Make sure you drain your composter on a regular basis. The leachate, as well as any compost tea, cannot be left sitting as it will turn anaerobic and will start to smell… It is very concentrated and must be diluted to the ratio of 1 to 5 volumes of water.
Compost tea is amazing fertiliser for your plants- world of worms in Kelowna


“Compost tea” is a liquid solution or suspension made by steeping compost in water. It is used as both a fertilizer and to prevent plant diseases. The liquid is applied as a spray to non-edible plant parts, or as a soil-drench (root dip), such as seedlings, or as a surface spray to reduce incidence of harmful diseases caused by pathogens. Compost tea has been shown to cause a 173.5% increase in plant growth by mass over plants grown without castings. These results were seen with only a 10% addition of castings.- Wikipedia –

A bucke of compost tea by world of worms in Kelowna
Compost tea brewing system by World of worms
Compost tea being used on plants in the greenhouse by World of Worms in kelowna