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

Updated April 2026 By the Old Cobblers Farm Team

Old Cobblers Farm™ Wicked Organics Bone Char

by Wicked Organics — 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 Ratio0-16-0
Derived FromCarbonized bone (100%)
Item FormGranular charite
Release SpeedVery slow-release
Application Rate2–5 lbs / 100 sq ft (beds) | 1–2 tbsp / gal soil (containers)
MethodWork into top 4–6" of soil
Frequency1x per season or as soil amendment
Sizes5 lb | 10 lb | 15 lb | 20 lb
SupportsAll crops, fruit trees, vegetable gardens, flower beds, compost systems
SetupsGarden beds, raised beds, containers, orchards, compost blending
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 Bone Char Bone Char Rock Phosphate Organic Rock Phosphate Triple Phosphate (not organic) Organic Granulated Rock Phosphate Organic Bone Meal (as P alternative) Bone Char Phostrell Bone Charcoal Bone Meal 3-15-0 Bone Char 0-16-0 Rock Phosphate Seabird Guano Triple Phosphate Bone Meal 3-15-0 Colloidal Phosphate
NPK 0-16-0 0-16-0 0-16-0 0-3-0 0-3-0 0-45-0 0-7-0 3-15-2000 0-16-0 0-20-0 0-16-0 3-15-2000 0-16-0 0-3-0 0-11-0 0-45-0 3-15-2000 0-3-0
Phosphorus 16.0% 16.0% 16.0% 3.0% 3.0% 45.0% 7.0% 15.0% 16.0% 20.0% 16.0% 15.0% 16.0% 3.0% 11.0% 45.0% 15.0% 3.0%
Potassium 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Form Granular charite
Sizes 5 lb | 10 lb | 15 lb | 20 lb 50 lb 50 lb 50 lb 5, 25, 50 lb 50 lb 5, 25, 40 lb 2, 20, 40 lb 6.5 lb 5, 25 lb 50 lb
Release Speed Very slow-release
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
3-15-2000
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
3-15-2000
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
3-15-2000
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