What leachate is
Leachate is the liquid runoff that collects at the bottom of a digestion container or flows through a drain. It comes from moisture in the feed, larval activity, and microbial processing—not from intentionally steeping frass in water.
In outreach and social posts, leachate is sometimes confused with “frass tea” or even with solid frass itself. On this site we keep the terms separate so operators know what they are handling and what claims apply to which product.
Why separation matters
Good system design routes liquid away from solids. That keeps the larval bed aerobic, reduces odor, and gives you two distinct harvest streams: crumbly frass for soil amendment and liquid leachate that may need its own treatment or disposal plan.
- Composition varies — depends on feed moisture, loading rate, and how long liquid sits in the sump.
- Not a substitute for frass — nutrient profile and handling differ from composted solid frass.
- Local rules — discharge to ground or sewer may be restricted; treat like an industrial or agricultural effluent if volume is significant.
Practical handling
Capture leachate in a tray, sump, or drain line—do not let the larval substrate sit waterlogged. Dilute or ferment before use only if you have a documented, safe protocol; default to cautious disposal until you know your stream. Never label leachate as frass or frass tea in marketing or application guides.
Research trail: Frass vs leachate vs frass tea.