Biochar Yield
50 lbs
Volume
5 ft³
Batches
1
Coverage
1,000 ft²
Typical: 3–10 lbs per 100 sq ft
Biochar Yield
50 lbs
25% conversion rate
Volume
5
ft³
Batches
1
Burn Time
3
hrs
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Inputs
Result
Yield = 200 × 0.25 = 50 lbs. Volume = 50/10 = 5.0 ft³. Feedstock = 200/35 = 5.7 ft³, fits in 15 ft³ cone kiln (1 batch). Coverage = 50/5 × 100 = 1,000 ft².
Inputs
Result
Yield = 500 × 0.30 = 150 lbs. Volume = 150/10 = 15 ft³. Feedstock = 500/20 = 25 ft³, fits in 30 ft³ retort (1 batch). Coverage = 150/5 × 100 = 3,000 ft².
About 20–30 lbs of biochar from 100 lbs of wood, depending on the feedstock. Hardwood yields ~25% (25 lbs), bamboo ~30% (30 lbs), and softwood ~20% (20 lbs). Kiln type also affects yield — retort kilns produce the highest quality biochar.
| Feedstock | Yield % | Biochar from 100 lbs | Best For |
|---|---|---|---|
| Hardwood | 25% | 25 lbs | General garden use |
| Bamboo | 30% | 30 lbs | Highest yield |
| Softwood | 20% | 20 lbs | Fast-growing supply |
| Nut Shells | 28% | 28 lbs | Dense, long-lasting |
Apply 3–10 lbs of biochar per 100 sq ft of garden bed, mixed into the top 6–8 inches of soil. Start with 5 lbs per 100 sq ft (a 5% soil volume mix). Always charge biochar with compost tea or fertilizer before adding to soil to prevent nitrogen tie-up.
A cone kiln is the best balance of cost, capacity, and quality for home biochar production. It processes 15 cu ft of feedstock in about 3 hours. TLUD stoves are cheaper but smaller (1 cu ft). Retort kilns make the purest biochar but cost $500+ and take 6 hours per batch.
Yes — biochar increases water retention by 18–25%, improves nutrient holding capacity (CEC) by 20–40%, and provides permanent habitat for beneficial soil microbes. Effects are permanent since biochar doesn't decompose for hundreds of years, unlike compost which breaks down in 1–2 seasons.
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Last Updated: Mar 19, 2026
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