Compost Tea: The Complete Walkthrough
This guide covers compost tea, rated an easy task, typically taking 24–48 hrs.
This is the expanded version of our compost tea guide, for anyone who wants the full detail rather than just the quick-reference card.
Steeped, not boiled
Compost tea is simply finished compost steeped in water to extract soluble nutrients and beneficial microbes, then applied as a liquid feed — a fast way to deliver a nutrient boost compared to solid compost.
What You'll Need
Keep these points in mind:
- Finished, mature compost or worm castings
- A bucket or barrel
- A porous bag or old pillowcase to hold the compost (optional but keeps it strainable)
- An aquarium pump for aeration (optional, improves quality)
How It's Done
Worth paying attention to:
- 1. Fill a porous bag with 1–2 handfuls of finished compost per litre of water, or add loose compost directly.
- 2. Submerge in a bucket of water — rainwater or dechlorinated tap water is best.
- 3. Steep for 24–48 hours, stirring occasionally, or aerate with a pump for better results.
- 4. Strain out solids if not using a bag.
- 5. Dilute if concentrated, and apply directly to soil or as a light foliar spray.
Troubleshooting
Keep these points in mind:
- Smells bad/anaerobic — brewed too long or without enough airflow; use within 48 hours and aerate if possible.
- No visible benefit — compost tea is a supplement, not a substitute for good soil-building; use alongside, not instead of, regular compost.
- Clogged sprayer — strain thoroughly before using in a spray applicator.
- Over-application — more isn't better; stick to a light, regular feeding rhythm rather than heavy, infrequent doses.
Ongoing Timing
Best time — throughout the growing season, timed with active growth phases. Duration — each batch brews in 24–48 hours and should be used fresh, within a day or two. Maintenance — brew a fresh batch every few weeks rather than trying to store it — it doesn't keep well. Signs of success — a rich brown liquid with an earthy, not foul, smell.
For the condensed printable version, head to the main guide page linked below.