Biochar in Containers & Potting Mix
Blend pre-charged biochar at 10–15 % by volume into fresh or refreshed potting mix. Improves aeration and extends wet-to-dry cycles.
Last updated April 18, 2026
The easy use case
Containers are where first-time biochar users usually have the best experience. A fresh potting mix is already a controlled medium. Adding 10–15 % charged biochar turns it into a medium with longer wet-to-dry intervals and better gas exchange at root depth.
Before you blend
- Charge. Compost tea soak (6–24 hours) or blend 1:1 with finished compost for two weeks. See the charging guide.
- Moisten. Wet the biochar before adding to dry potting soil.
Application
- Rate: 10–15 % of potting mix by volume.
- Example: For a 20 L pot, blend roughly 2–3 L of charged biochar through the whole mix before potting.
- Top-dress refresh: For existing pots, pull the top 3–4 cm of soil, fold in a thin layer of charged biochar, and replace. Water in.
Coverage from our bags
One 6.5 L bag holds 6.5 litres of biochar (1.5 kg).
| Container size | Biochar for a 12 % blend | Bags |
|---|---|---|
| 20 cm pot (~4 L) | ~0.5 L | one bag covers a dozen pots |
| 30 cm pot (~14 L) | ~1.7 L | one bag covers three to four |
| 50 cm planter (~35 L) | ~4.2 L | one bag, with some left over |
| Balcony collection (10 × 30 cm pots) | ~17 L | three bags |
One thing to watch
If you skip charging, container mixes will sometimes yellow slightly in week one as biochar equilibrates with the nutrient profile. Not a deficiency, not harmful — but easier to avoid by pre-charging.