Organic Phosphorus + Carbon
Best Bone Char Fertilizer (0-16-0): Slow-Release Organic Phosphorus with Biochar-Like Carbon for Lasting Soil Improvement Buy on Old Cobblers Farm
Bone char isn't just a fertilizer — it's a soil builder. Carbonized bone delivers 16% phosphorus that releases over months, not days, while the carbon matrix permanently improves soil structure, water retention, and microbial habitat. One application keeps working for years.
Old Cobblers Farm™ Wicked Organics Bone Char
by Organic Fertilizer — Littleton, NH
0-16-0
N-P-K Ratio
"The longest-lasting organic phosphorus source available. 16% P₂O₅ locked in a carbon matrix releases slowly through microbial activity while the charred bone structure acts as a permanent soil conditioner — improving CEC, water retention, and microbial habitat."
16%
Phosphorus (P₂O₅)
Carbon
Permanent Soil Builder
250 ft²
Max Coverage / bag
4 Sizes
5, 10, 15, 20 lbs
16% Phosphorus in Carbon Matrix
Carbonized at high temperatures, bone char locks phosphorus into a stable carbon structure that releases slowly over months. The slowest, most sustained organic P delivery available.
Permanent Soil Improvement
Like biochar, the carbon in bone char doesn't decompose. It permanently increases soil cation exchange capacity (CEC), water retention, and provides habitat for beneficial microbes.
Calcium + Carbon
Bone char delivers calcium for cell wall strength and fruit quality alongside the carbon matrix. Dual-purpose amendment that feeds plants and builds soil simultaneously.
Soil Amendment Rates
2–5 lbs per 100 sq ft worked into the top 4–6 inches. For containers, 1–2 tablespoons per gallon of soil mix. Can also be pre-charged by composting 50/50 with compost.
Microbial Habitat Builder
The porous carbon structure of bone char provides massive surface area for beneficial soil microbes to colonize. More microbes = better nutrient cycling = healthier plants.
Improves Water Retention
Carbon holds water in sandy soils and improves drainage in clay soils. Bone char moderates soil moisture in both directions — a permanent structural improvement.
Organic & Sustainable
Made from animal bone — a byproduct of the food industry. Carbonization makes nutrients stable and long-lasting. Approved for organic production systems.
Trusted by 20,000+ Growers
Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.
| NPK Ratio | 0-16-0 |
| Item Form | Granular charite |
| Coverage | 100–250 sq ft per 5 lb bag |
| Category | Organic Fertilizer |
| Type | Single-Ingredient Meals |
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb |
| NPK | 0-16-0 |
| Nitrogen | 0% |
| Phosphorus | 16% available phosphate |
| Potassium | 0% |
| Bonus | Carbon matrix, Calcium |
| Form | Granular char |
| Rate | 2–5 lbs / 100 sq ft |
| Method | Work into top 4–6" of soil |
| Sizes | 5, 10, 15, 20 lb bags |
| Best For | All crops, soil building, compost blending, long-term P delivery |
What We Love
✓ 16% slow-release phosphorus locked in stable carbon matrix
✓ Permanent soil improvement — carbon doesn't decompose
✓ Increases CEC, water retention, and microbial habitat
✓ Dual-purpose: fertilizer + soil conditioner in one product
✓ Organic and sustainable — approved for organic production
Worth Noting
— Very slow release — not for quick phosphorus correction
— Black color may temporarily darken soil surface
Buy on Old Cobblers Farm →
Available in 5 lb | 10 lb | 15 lb | 20 lb
| Feature | Old Cobblers Farm™ Wicked Organics Bone Char Old Cobblers Farm | Bone Char Organically Done | Bone Char North Country Organics | Rock Phosphate Down To Earth | Organic Rock Phosphate Espoma | Triple Phosphate (not organic) Espoma | Organic Granulated Rock Phosphate Fertoz | Organic Bone Meal (as P alternative) Down To Earth | Bone Char North Country Organics | Phostrell Fertrell | Bone Charcoal Fertrell | Bone Meal 3-15-0 Down To Earth | Bone Char 0-16-0 Compost Werks | Rock Phosphate Down To Earth | Seabird Guano Down To Earth | Triple Phosphate Espoma | Bone Meal 3-15-0 Greenway Biotech | Colloidal Phosphate Calphos |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | 0-16-0 | 0-16-0 | 0-16-0 | 0-3-0 | 0-3-0 | 0-45-0 | 0-7-0 | 3-15-0 | 0-16-0 | 0-20-0 | 0-16-0 | 3-15-0 | 0-16-0 | 0-3-0 | 0-11-0 | 0-45-0 | 3-15-0 | 0-3-0 |
| Form | Granular charite | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Coverage | 100–250 sq ft per 5 lb bag | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed |
| Price / Size | 5 lb | 10 lb | 15 lb | 20 lb | $15–$20 / 5 lb; $55–$70 / 50 lb | $40–$55 / 50 lb | $12–$15 / 5 lb | $12–$16 / 7.25 lb | $12–$16 / 6.5 lb | $25–$35 / 50 lb | $13–$16 / 5 lb | $30-45 (50 lb) | $35-50 (50 lb) | $30-40 (50 lb) | $8 (5 lb), $35 (50 lb) | $25-35 (50 lb) | $10 (5 lb) | $11 (2 lb), $45 (20 lb) | $12-15 (6.5 lb) | $15 (5 lb) | $20-30 (50 lb) |
| Our Take | The longest-lasting organic phosphorus source available. 16% P₂O₅ l... | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | **Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity. | — | — | — | — | — | — | — | — | — | — |
The Competition
Bone Char
by Organically Done
0-16-0
N-P-K
Price$15–$20 / 5 lb; $55–$70 / 50 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Bone Char
by North Country Organics
0-16-0
N-P-K
Price$40–$55 / 50 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Rock Phosphate
by Down To Earth
0-3-0
N-P-K
Price$12–$15 / 5 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Organic Rock Phosphate
by Espoma
0-3-0
N-P-K
Price$12–$16 / 7.25 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Triple Phosphate (not organic)
by Espoma
0-45-0
N-P-K
Price$12–$16 / 6.5 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Organic Granulated Rock Phosphate
by Fertoz
0-7-0
N-P-K
Price$25–$35 / 50 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Organic Bone Meal (as P alternative)
by Down To Earth
3-15-0
N-P-K
Price$13–$16 / 5 lb
**Bone char is an extremely niche category.** Only Organically Done and North Country Organics sell retail bone char products. Rock phosphate (0-3-0) provides far less available phosphorus per pound than bone char's 16%. This represents minimal competition and a major market opportunity.
Bone Char
by North Country Organics
0-16-0
N-P-K
Sizes50 lb
Price$30-45 (50 lb)
IngredientsCalcined (kilned) bone meal; 32% total P2O5, ~30-34% calcium
OrganicOMRI Listed
Phostrell
by Fertrell
0-20-0
N-P-K
Sizes50 lb
Price$35-50 (50 lb)
IngredientsBlend of bone char + aragonite; high phosphorus + calcium
OrganicOrganic certifiable
Bone Charcoal
by Fertrell
0-16-0
N-P-K
Sizes50 lb
Price$30-40 (50 lb)
IngredientsPure bone char; 32% total P2O5, 33% calcium
OrganicOrganic certifiable
Bone Meal 3-15-0
by Down To Earth
3-15-0
N-P-K
Sizes5, 25, 50 lb
Price$8 (5 lb), $35 (50 lb)
IngredientsSteamed bone meal; 18% calcium (different process than char)
OrganicOMRI, CDFA OIM
Bone Char 0-16-0
by Compost Werks
0-16-0
N-P-K
Sizes50 lb
Price$25-35 (50 lb)
IngredientsWholesale bone char; OMRI certified for organic
OrganicOMRI Listed
Rock Phosphate
by Down To Earth
0-3-0
N-P-K
Sizes5, 25, 40 lb
Price$10 (5 lb)
IngredientsColloidal rock phosphite; 18% calcium, slow-release
OrganicOMRI, CDFA OIM
Seabird Guano
by Down To Earth
0-11-0
N-P-K
Sizes2, 20, 40 lb
Price$11 (2 lb), $45 (20 lb)
IngredientsFossilized seabird guano; 11% phosphorus, high calcium
OrganicOMRI, CDFA OIM
Triple Phosphate
by Espoma
0-45-0
N-P-K
Sizes6.5 lb
Price$12-15 (6.5 lb)
IngredientsConcentrated superphosphate; fast-acting (NOT comparable to organic)
OrganicNOT organic (synthetic)
Bone Meal 3-15-0
by Greenway Biotech
3-15-0
N-P-K
Sizes5, 25 lb
Price$15 (5 lb)
IngredientsBovine bone meal; 24% calcium (steamed, not calcined)
OrganicOrganic
Colloidal Phosphate
by Calphos
0-3-0
N-P-K
Sizes50 lb
Price$20-30 (50 lb)
IngredientsColloidal clay-calcium-phosphate complex; 18% calcium, 3% P2O5
OrganicNOP Listed
16% Phosphorus in Carbon Matrix
Carbonized at high temperatures, bone char locks phosphorus into a stable carbon structure that releases slowly over months. The slowest, most sustained organic P delivery available.
Permanent Soil Improvement
Like biochar, the carbon in bone char doesn't decompose. It permanently increases soil cation exchange capacity (CEC), water retention, and provides habitat for beneficial microbes.
Calcium + Carbon
Bone char delivers calcium for cell wall strength and fruit quality alongside the carbon matrix. Dual-purpose amendment that feeds plants and builds soil simultaneously.
Soil Amendment Rates
2–5 lbs per 100 sq ft worked into the top 4–6 inches. For containers, 1–2 tablespoons per gallon of soil mix. Can also be pre-charged by composting 50/50 with compost.
Common Questions
