DIY Organic Fertilizer Recipes for Bonsai and Gardens: Nutrient Values and Why Human Vitamins Aren't Ideal

Organic Fertilizer Ingredients & N-P-K Values

Approximate nutrient ratios (N-P-K) for common organic materials:

Material	N-P-K	Notes
Eggshells (blended)	12-4-1	High calcium
Ground seashells	9-7-0	Must be fine powder
Wood ashes	0-3-14	High potassium, raises pH
Crushed granite	0-0-5	Slow-release minerals
Epsom salts	0-0-0	Magnesium + sulfur
Feathers (shredded)	15-0-0	High nitrogen
Hair (shredded)	14-0-0	Slow-release nitrogen
Fish emulsion	5-3-3	Balanced, fast-acting
Horse manure (aged)	7-3-6	Good all-around
Duck manure (aged)	6-14-5	High phosphorus
Chicken manure (aged)	11-8-5	High nitrogen, hot—compost first
Rabbit manure (aged)	24-14-6	Very high N—use sparingly
Worm castings	5-5-3	Perfect balance, microbial inoculant
Coffee grounds	20-3-2	High N, slightly acidic, attracts worms

Other Organic Boosters

• Used aquarium water: Rich in nitrogen, beneficial bacteria.
• Beer: Enzymes + nitrogen for soil life.
• Ammonia + Gatorade (heavily diluted): Trace minerals + N—use extreme caution.
• Bone meal: Slow-release phosphorus.
• Blood meal: Fast-release nitrogen.
• Cottonseed meal: Slow-release nitrogen, acidifying.
• Sugar: 1 lb per 250 sq ft for microbial boost.

Bonsai-Specific Caution

Bonsai is a precise art. Wrong fertilizer alters growth patterns undesirably. Consult Brent Walston's "Fertilizing Your Bonsai" before experimenting.

Why Human Vitamins Don't Work on Plants

A California science fair project tested human vitamins on parsley:

• Vitamin D & calcium: increased growth.
• Iron & vitamin C: negative or no effect.

Plants and humans have fundamentally different metabolisms. Chelated iron helps chlorotic plants, but ferrous sulfate (human supplement) may not. Human-grade calcium is absurdly expensive as fertilizer. Plants need a balanced mineral diet, not a multivitamin.

The Anthropomorphism Trap

We talk to plants, play music, feed them vitamins. But plants are a separate kingdom. They fix nitrogen from air (clover), synthesize carbohydrates from sunlight, and thrive on N-P-K plus micronutrients. Feeding them human supplements is fun but ineffective. Buy proper fertilizer—it's cheaper, healthier, and more ethical.