Skip to main content

Worm Castings (Vermicompost): Complete Guide

Oregon State Extension

Earthworm-processed organic matter packed with beneficial microbes, humic acids, and plant-available nutrients in a 2-1-1 ratio. Virtually impossible to burn even on delicate seedlings, making it the safest potting amendment available. Mix 10-20% into container soil or topdress houseplants with 1/4 inch. Expensive at roughly $1.50 per pound, so use regular compost for large garden beds instead.

Key Facts

2N
1P
1K
N 2% Nitrogen: leaf and stem growth
P 1% Phosphorus: roots and flowers
K 1% Potassium: health and disease resistance
Learn more about NPK
NPK Ratio
2N
1P
1K
N 2% Nitrogen: leaf and stem growth
P 1% Phosphorus: roots and flowers
K 1% Potassium: health and disease resistance
Learn more about NPK
Formgranular
Application Rate1/4 inch topdress or mix 10-20% into potting soil
Price~$1.5/lb est.
Release Speedslow
Burn Riskvery low
organicgranular

What is Worm Castings (Vermicompost) Best For?

seedlingshouseplantscontainer gardenstransplantsraised beds

When Should You Use Worm Castings (Vermicompost)?

Use in seed starting mixes, as a houseplant topdress, or mixed into container potting soil.

When Should You NOT Use Worm Castings (Vermicompost)?

Expensive for large-scale garden applications. Use regular compost instead.

Source:Oregon State Extension