Using Worm Castings

How to use worm castings in a soil mix?

Worm castings can be used in a multitude of ways – mixed into a soil mix, a soilless mix, or as a tea or slurry.

Usually worm castings is thought of as an additive. Recommendations vary wildly, but I would recommend adding one tenth to one fifth in any organic mix (10-20%).

Top dressing with worm castings would work well, too, especially with indoor containers. Making a worm castings tea by steeping the castings in clean well aerated water makes for a life giving plant-nutrient. I recommend filtering worm tea before use and returning the dregs into the worm bin after a couple of rounds.

One can use plain worm castings as a growing medium, and in my experience it works very well. But usually finished worm castings tends to be mud-like in consistency, and needs something to aerate and lighten up the texture. Perlite and expanded clay work very well for this. 50% of expanded clay (multiple size) and 50% worm castings makes for a nice quick-n-dirty primo soil(less) mix.

Bare basics of a mix:

40% castings 30% perlite 30% vermiculite"

102% Hyper Veg Mix

* 25% coco peat
* 25% expanded clay
* 50% worm casting
* 2% alfalfa meal pellets
* 1/4 tablespoon of dolomite lime per liter (1 per gal)
* lemon juice (or 8% citric acid solution)
* seaweed extract according to taste
* silicon nutrient additive


– This is a guideline, not a recipe. Know your ingredients!
– If things get too sticky, muddy or water retaining with the worm castings, add more coco peat, peat, perlite or expanded clay.
– The stretching due to alfalfa can last up to 5 or more weeks.
– For alfalfa meal pellets 2% is a careful estimate. More can be used if the plants can take it.
– This mix should last about 4 weeks, ie. supply the plant with nutrients during the vegetative period, PK and N+Mg+Ca additive may be needed in bloom.

Meek Flowering Mix

* Worm castings, from bin fed with fruit and vegetables and peels (High K, Medium P).
* Optionally in the first 4 weeks of flowering, add as needed: Pinch of dolomite lime or epsom salts Pinch of gypsym Pinch(es) of clean, pure wood ash.

Mix in a bucket of water, and filter solids. Water during flowering.


– This is a guideline, not a recipe. Know your ingredients!
– Yields very vivid aromatic tones
– Basically a high K + P + Mg + Ca + S solution – all that’s needed in bloom.
– N supplementation may also be necessary.

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