Reviewed September 2026 against USDA NASS, USDA Census of Agriculture, and farmdoc daily (University of Illinois).

Try it: Run your own numbers →

What Fertilizer Is Used in Organic Farming?

Table of Contents

What Fertilizer Is Used in Organic Farming?

Organic farming uses fertilizers derived from natural sources — compost, aged animal manure, bone meal, feather meal, fish emulsion, and mined minerals like rock phosphate and greensand — instead of synthetic, factory-manufactured nutrients. In the United States, certified organic farms covered 4.9 million acres in 2021, including 3.6 million acres of cropland, across 17,048 certified organic farm operations, according to the USDA National Agricultural Statistics Service (NASS) 2021 Census update and the 2022 Census of Agriculture Organic Highlights. Sales of certified organic commodities reached $9.6 billion in 2022, per USDA’s Census of Agriculture.

The U.S. organic fertilizer market itself was valued at $1.34 billion in 2026 and is projected to grow at an 8.05% compound annual growth rate through 2031, according to Markets and Data industry research. Manure-based products are the single largest category, holding 46.9% of that market as of 2025 — reflecting how central animal manure remains to organic nutrient management even as compost, meal-based, and mineral products expand.

Does organic farming use fertilizer at all? Yes — the distinction is not “no fertilizer,” it’s non-synthetic sourcing plus a slower, biologically mediated release into the soil. External inputs are minimized, and the goal is to recycle nutrients within or near the farm system rather than import them as water-soluble salts.

• ✔ Organic fertilizer is made from plant, animal, or mineral sources
• ♻ Nutrient cycling reduces reliance on synthetic fertilizers
• 🔬 Microbial activity mineralizes organic nutrients into plant-available forms over the season
• 🌱 Slow-release nutrition replaces the rapid, chemical-driven feeding of synthetic NPK
• 🛡️ Certified organic sales reached $9.6 billion in the U.S. in 2022, per USDA

Types of Organic Fertilizers: The Natural Choices

Here are the organic fertilizers actually used on certified farms and in home gardens, and what each one contributes to soil health and plant nutrition.

• 🌿 Compost: Decayed plant matter, food waste, and sometimes animal manure, composted to provide steady, slow-release nutrients while improving soil structure and organic matter.
• 💩 Manure: Well-rotted manure from cattle, horses, or poultry delivers nitrogen (N), phosphorus (P), and potassium (K) together, and is the largest single category in the U.S. organic fertilizer market at 46.9% share (2025, Markets and Data).
• 🦴 Bone Meal: Ground animal bones supplying roughly 12–20% phosphorus, used to boost root and flower development in soils low in P. Often applied in organic vegetable and fruit plantings.
• 💧 Fish Emulsion: Liquid fertilizer from fish processing, high in nitrogen and micronutrients, fast-acting and suited to leafy crops.
• 🐔 Blood Meal & Feather Meal: Nitrogen-rich byproducts (blood meal 12–14% N, feather meal up to 12% N) used as top-dressings or worked into planting holes for quick green-up.
• 🌵 Rock Phosphate & Greensand: Mineral deposits supplying phosphorus (15–30% P in rock phosphate) and potassium plus micronutrients (3–7% K in greensand).
• 🌱 Green Manures/Cover Crops: Clover, vetch, or rye grown and incorporated into soil to fix nitrogen, improve structure, and feed microbial cycling.

Try Farmonaut’s satellite-based monitoring to track soil health and fertilizer impact in real-time – Click Here

Key Insight

What Do 13-13-13, 14-14-14, and CAN Fertilizer Actually Do?

These three searches come up constantly alongside organic fertilizer questions because farmers and gardeners comparing options need to know what the conventional baseline actually contains. None of the three below are organic products — they’re synthetic, water-soluble blends — but understanding them clarifies exactly what organic alternatives are substituting for.

• 13-13-13 fertilizer is a balanced NPK blend supplying 13% nitrogen, 13% phosphate (P₂O₅), and 13% potash (K₂O) by weight, per Yara’s fertilizer specifications. It’s used as an all-purpose starter or maintenance feed for vegetables, lawns, and field crops that need equal parts of all three macronutrients rather than one nutrient emphasized over the others.
• 14-14-14 fertilizer is the same balanced concept at a slightly higher concentration — 14% nitrogen, 14% phosphate, 14% potash — and is common in slow-release, resin-coated granule products used for season-long feeding of container plants, nursery stock, and turf.
• CAN fertilizer (Calcium Ammonium Nitrate) is a nitrogen fertilizer, typically formulated around 27% nitrogen, that combines ammonium nitrate with calcium carbonate. The calcium carbonate buffers soil acidification, which is CAN’s main practical advantage over straight ammonium nitrate or urea in fields that are already borderline acidic. It’s applied as a top-dressing on cereals and grassland where fast nitrogen uptake is the goal.

On the most widely used nitrogen fertilizer question specifically: in the United States, corn is the dominant destination for nitrogen fertilizer, absorbing 78% of all nitrogen applied nationally in 2024, according to farmdoc daily analysis of USDA data. U.S. farmers used approximately 12.5 million tons of nitrogen fertilizer in 2024, with corn fields averaging 151.8 lbs of nitrogen per acre and wheat averaging 77.15 lbs per acre that same year. Corn’s nitrogen-use efficiency has improved to roughly 0.85 lbs of nitrogen per bushel produced in 2024, down from higher figures decades earlier — meaning growers now extract more yield per pound of nitrogen applied than in the past. None of this tonnage breaks out which specific blend (urea, anhydrous ammonia, UAN solution, or CAN) dominates by product name in the farmdoc dataset; for a current product-level breakdown, USDA’s annual Trends in Fertilizer Use report is the source to check.

Organic vs. Conventional: The Difference in Fertilizer and Philosophy

The opposite of organic farming is conventional (industrial) farming, which relies on synthetic fertilizers like the 13-13-13, 14-14-14, and CAN blends above, delivered at high concentration for fast uptake. Organic farming relies on natural fertilizers, crop rotation, and resource recycling instead.

• 🔍 Conventional systems: Synthetic nutrient sources give rapid nutrient availability — the 151.8 lbs/acre of nitrogen U.S. corn receives is almost entirely synthetic — but carry runoff and leaching risk if over-applied.
• 🌱 Organic systems: Emphasize soil health, biodiversity, slow nutrient release, and ecosystem resilience; the U.S. organic fertilizer market’s manure-based segment alone was valued enough to hold 46.9% share of a $1.34 billion market in 2025–2026.
• 🌍 Ecological impacts: Organic fertilizers avoid chemical residues entering waterways, reducing harm to aquatic ecosystems and pollinators.

Where organic farming prioritizes recycling and soil biology, conventional farming relies on externally sourced, water-soluble synthetic inputs like CAN and 13-13-13 blends for immediate crop response.

Characteristics of Organic Fertilizers

What is actually in organic fertilizer, and what sets its behavior apart from a synthetic bag of 14-14-14? Four characteristics define the category:

• Non-synthetic origin: Sourced from plant residues, animal byproducts (manure, bone, blood, feather), or mined minerals (rock phosphate, greensand) — never manufactured via industrial nitrogen fixation or acid processing the way synthetic NPK is.
• Slow, biologically mediated release: Nutrients are locked in organic molecules and mineralized gradually by soil microbes, rather than dissolving immediately like CAN or 13-13-13 granules.
• Bundled nutrients plus organic matter: A ton of compost or manure adds carbon and soil structure alongside N-P-K; a bag of synthetic fertilizer adds only the labeled nutrients.
• Variable, lower nutrient concentration: Compost typically supplies 1–3% nitrogen by weight versus CAN’s ~27% or 13-13-13’s 13% — meaning organic fertilizers are usually applied in much larger volumes per acre to deliver equivalent nutrient loads.

On exact nitrogen percentages for compost, aged manure, or pelletized poultry manure specifically: USDA does not publish a single unified standard, because content varies by feedstock and composting method. The reliable way to know your own material’s content is a laboratory nutrient analysis of the specific batch — most state extension services and land-grant university soil labs offer this as a paid test, typically reported in days to a few weeks.

Nutrient Cycling, Soil Health, and Microbial Activity

Compost, manure, crop residues, and natural minerals form the backbone of fertility in organic systems by feeding the biology that ultimately makes nutrients available to plants.

• ✔ Compost and manure feed soil microorganisms, which break down organic matter and cycle nutrients for plant uptake across the season.
• 🌱 Crop residues (stems, roots, leaves) left on the soil add organic matter and help retain moisture.
• ♻️ Green manures and cover crops fix nitrogen and provide habitat for beneficial soil life.
• 🔬 Microbial mineralization converts organic nutrients into plant-available forms — the process that makes compost’s 1–3% nitrogen usable despite its low concentration relative to CAN’s 27%.
• 🛡️ Healthy soil biology reduces pest and disease pressure without chemical intervention.

Pro Tip

Crop Rotation, Natural Fertilizers, and Healthy Food Chains

Crop rotation and natural fertilizers work together in organic systems to keep both soil and downstream food chains healthy.

• 🔁 Prevents Nutrient Depletion: Different crops draw different nutrients; rotating prevents soil exhaustion.
• 🦠 Breaks Pest & Disease Cycles: Crop diversity disrupts pathogen life cycles, reducing reliance on chemical intervention.
• 🌱 Improves Soil Structure: Root residues from varied crops and green manures enhance aeration and water retention.
• 🌾 Fixes Nitrogen: Legumes (clover, beans) fix atmospheric nitrogen for subsequent plantings, cutting external fertilizer need.
• ♻️ Returns Carbon and Organic Matter: Continuous residue cycling builds soil carbon and microbial activity.

Crops grown in actively cycling, biologically diverse soils carry fewer chemical residues and support more stable ecosystems both on the farm and downstream in waterways and food supply chains.

Common Mistake

Organic Nitrogen Substitution Calculator

Use your own compost or manure nitrogen test result and target crop nitrogen rate to estimate how many tons per acre of organic material would supply the same nitrogen as a synthetic application.

Assumes 2,000 lbs per ton and that only the first-year plant-available fraction of total nitrogen (commonly 30–50% for composted manure, lower for fresh manure or high-carbon compost) counts toward the target rate. Excludes phosphorus, potassium, moisture content, and application/spreading losses — get your material's actual N% and availability from a lab test rather than a label estimate.

5 Tips and Pitfalls When Using Organic Fertilizers

• 🌧️ Don't fertilize before heavy rain — nutrients can leach out before plants take them up.
• 👩‍🌾 Rotate your amendments — alternate compost, manure, and green manures for balanced nutrition.
• 🔍 Test your soil and your compost/manure — organic systems can develop deficiencies or excesses if nutrient content is assumed rather than measured.
• 🗓 Apply based on crop demand and soil fertility cycles, not a fixed calendar date.
• 🚜 Avoid over-application — more organic material isn't automatically safer; runoff and nutrient loading can still occur.

Investor Note

Common Organic Fertilizers and Their Nutrient Contributions

Common Mistake

Monitor Real-Time Crop Health & Inputs on Android – Download Farmonaut

Try Farmonaut on iOS for soil monitoring, carbon management, and more!

How Farmonaut Can Support Sustainable Agriculture

Farmonaut makes satellite-driven, data-powered insights for sustainable agriculture accessible worldwide. Our platform enables:

• 🌍 Large-Scale Crop and Soil Monitoring: Use NDVI and other indices to observe vegetation health, fertilizer impact, and soil trends.
• 🔒 Blockchain-based Traceability: Build transparency in organic supply chains. Read More
• ♻️ Carbon Footprinting: Track and report the carbon sustainability of organic and regenerative practices. Details
• 🚜 Fleet Management: Optimize farm machinery use to reduce environmental impact. How it Works
• 💰 Agri-Loan and Insurance Verification: Use satellite data for transparent, fraud-resistant crop loan approvals. See Details

Whether you're an individual farmer, agricultural enterprise, or finance provider, Farmonaut offers modular tools to scale productivity, reduce environmental footprint, and maintain healthy food chains.

Learn More: Our crop, plantation, and forest advisory platform integrates real-time monitoring for all land-based operations.

Frequently Asked Questions