Super Easy Way To Make Worm Casting Compost Extract
- Mar 4
- 4 min read
Updated: Mar 10
Worm casting compost extract is an amazing soil amendment for both indoor and outdoor plants. It offers the power of microorganisms and micronutrients, which are introduced into your soil in liquid form, penetrating the root zone. It helps defend against diseases and pests and is especially beneficial for seedlings and saplings. There are many interesting studies being conducted today to better understand compost extracts and compost teas. We'll explain how to make a worm casting extract as a safe, easy way to add microbes to the soil.
Here's what you will need before making worm casting compost extract.
• 5 gallon bucket
• Mesh bag
• 5 lbs of Worm Castings
• De-chlorinated water (Rain water, distilled water, or off-gassed tap water.)
• Un-sulfured Molasses (1tbs)
Let's Make some worm casting compost extract.
We like to stick to a 1:1 castings-to-water ratio: 1 lb of castings to 1 gallon of water. In this post we will be working with 5 lbs of castings to 5 gallons of water.
First, fill a 5-gallon bucket with room-temperature rainwater or de-chlorinated water. This doesn't have to be exact, but as a reference, we fill the bucket about 85% full. This allows room to place the bag in the water without spilling anything.
Next, add 1 lb of castings to a mesh bag, making sure the bag will stay closed when you agitate it to release the microbes.
Add a tablespoon of molasses to the water.
Pro Tip: Dilute the molasses with a small amount of water, creating a syrup. This will help the molasses dissolve into the bucket more effectively and quickly. We also like to swirl the molasses syrup—just a few swirls, nothing too crazy. This helps the molasses spread throughout the water.
Now it's time to extract the microbes from the castings.
We’ll do 5 repetitions, using 1 lb of castings at a time. Think of it like brewing 5 Earl Grey tea bags in one cup. This method will release more microbes into the water than adding all 5 lbs of castings at once.
Once you have 1 lb of castings in the bag, dunk it into the water 4 or 5 times. Then, while the bag is submerged, use one hand to gently scratch the outside of the bag for 1 to 2 minutes. This will release the microbes that are stuck to the castings and suspend them in the water.
At this point, you’ve completed one repetition. Repeat the process until you've used all the castings from your 5-lb box.
It's time to water the garden.
Depending on the microbiology within the worm castings, some applications may be stronger than others. Thankfully, you cannot over-add microbiology to the soil or plants. The plants will take what they need from the microorganisms and micronutrients, while the soil will retain the rest. Five gallons can cover an acre of garden, pasture, or lawn when sprayed or used as a soil amendment. However, this will not provide the water that plants may need. Water as usual with de-chlorinated or rain water. Remember, to not kill all the beneficial microbes that we just added to the soil by watering with chlorinated water from a well or city water source.
When watering our garden, we add the 5 gallons to a watering cans to water our 1/16-acre garden, four raised beds, and two plum trees. We’ve also added it to a larger water barrel and watered our garden with a sprinkler. There is a potential risk of gumming up the sprinkler head with the molasses sugar, but it’s a low risk.
Common Questions:
How often should I add worm casting compost extract to my garden or lawn?
We recommend adding it as a soil and plant amendment three times a year. First, in the spring, after you plant your garden or before your first mowing. Second, in early summer or before temperatures get too hot. If temperatures and soil are too hot, you can kill the microbes before they have a chance to help. Third, in late season, right before fall planting, to help the plants and soil throughout the winter.
What micro-biology is in worm casting compost extract?
How soon should I use my worm casting compost extract?
What do I do with my spent castings?