How to Make Your Own Fertilizer

Originally published: February 2023 | Updated: September 2026

Summary

Making your own fertilizer is less about inventing a universal recipe and more about recycling farm nutrients responsibly. Begin with a soil test, then use finished compost, vermicompost, properly managed manure, and cover crops to address measured crop needs.

Test variable materials, calculate application rates, protect water and food safety, and keep good records. A careful plan can lower input costs, reduce waste, and build long-term soil health without creating new nutrient problems.

Whether you’re growing acres of crops or a small kitchen garden, fertilizer is an important part of making sure your plants are healthy and productive. Making your own fertilizer is a great way to save money, reduce waste, and customize the amount of nutrients your plants need to thrive.

Read on to learn how you can use organic matter like compost and livestock bedding to make your own fertilizer on-farm.

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Best Answer

The safest way to make your own fertilizer is to start with a soil test, then use well-finished compost, vermicompost, cover crops, or properly composted manure to supply the nutrients your soil actually needs. Avoid guessing at homemade chemical blends or applying raw manure near harvest. Test both soil and manure-based amendments when possible, calculate application rates from crop needs, and keep records so you can improve your fertility plan over time.

Fertilizer supports healthy plant growth by replacing nutrients that crops remove from the soil. Making some of your own fertility inputs can reduce waste, lower costs, and build healthier soil—but only when you know what your soil needs and what your homemade material contains.

The best do-it-yourself fertilizer is rarely a bucket of household ingredients mixed from a generic recipe. For most farms and gardens, it is a planned combination of soil testing, finished compost, cover crops, vermicompost, and carefully managed manure. This guide explains how to produce and use those materials safely.

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What does fertilizer do?

Plants need at least 17 essential nutrients. Carbon, hydrogen, and oxygen come primarily from air and water. The remaining nutrients come from the soil or from fertilizers and soil amendments.

The three numbers on a fertilizer label represent:

• Nitrogen (N): Supports leafy, vegetative growth and chlorophyll production.

• Phosphorus (P): Supports energy transfer, root growth, flowering, and seed formation.

• Potassium (K): Helps regulate water movement, strengthen plants, and support stress tolerance.

Plants also need secondary nutrients, including calcium, magnesium, and sulfur, plus small amounts of micronutrients such as boron, copper, iron, manganese, molybdenum, nickel, chlorine, and zinc.

More fertilizer is not always better. Excess nutrients can injure crops, create imbalances, waste money, and move into waterways. Compost and manure can also raise phosphorus, potassium, salts, or soil pH to undesirable levels when applied repeatedly.

Start with a soil test

Before making or applying fertilizer, send a representative soil sample to a reputable laboratory or your local Cooperative Extension service. A soil test can reveal pH, organic matter, and available nutrient levels, then provide crop-specific recommendations.

Use the results to answer three questions:

1. Which nutrients are deficient?

2. How much of each nutrient does the crop require?

3. Which amendment can meet that need without overapplying another nutrient?

For example, manure compost may supply nitrogen but also contain significant phosphorus. Applying enough compost to meet the full nitrogen requirement every year can eventually create excessive soil phosphorus. Soil tests and amendment analyses help prevent that problem.

Retest on a regular schedule and sample comparable areas separately. Different fields, high tunnels, orchards, and garden beds can have very different fertility needs.

What Are the Best Home Fertilizer Recipes?

Fertilizer recipes vary depending on the type of plant you are growing; some fertilizers are made specifically for strawberries, tomatoes, or fruit trees in your orchard. Fertilizer recipes also vary based on whether you are using organic or non-organic ingredients. There are so many recipes out there to choose from.

Five practical ways to make fertilizer on the farm

1. Make finished compost

Finished compost is one of the most useful homemade soil amendments. It returns organic matter and a broad range of nutrients to the soil, improves water-holding capacity, and supports soil biology. However, compost usually releases nutrients more slowly and in less predictable amounts than a labeled commercial fertilizer.

To build a compost pile:

1. Combine carbon-rich "browns," such as dry leaves, straw, and clean bedding, with nitrogen-rich "greens," such as fresh plant residue, grass clippings, and manure.

2. Keep the pile moist like a wrung-out sponge, not waterlogged.

3. Maintain airflow by using bulky materials and turning the pile as needed.

4. Monitor temperature if the compost contains manure or will be used in a certified organic system.

5. Let the compost cure after active heating ends.

Finished compost should be dark, crumbly, and earthy-smelling, with few recognizable feedstocks. A commercial compost test can measure nutrient content, maturity, pH, soluble salts, and the carbon-to-nitrogen ratio before field application.

For certified organic production, follow your Organic System Plan and USDA National Organic Program requirements. USDA guidance allows multiple compliant composting methods, but the process and records must demonstrate that the material is managed safely. Always confirm requirements with your certifier.

2. Produce vermicompost

Vermicompost is made as earthworms and microorganisms process organic material. It is well suited to smaller operations, greenhouses, and farms with a steady supply of suitable plant residues.

Use a ventilated bin or bed in a shaded location. Add moist bedding such as shredded paper, mature leaves, or partially decomposed plant material, then feed worms modest amounts of fruit and vegetable scraps. Avoid meat, dairy products, oils, pet waste, and materials contaminated with herbicides or other chemicals.

Keep the bedding moist and protect the worms from extreme heat or cold. Harvest the dark, fine castings after the feedstock has been thoroughly processed. Vermicompost can be incorporated into potting mixes or applied to soil in modest amounts.

If manure is used as feedstock (or if the farm is certified organic) follow applicable food-safety rules and consult the operation's certifier. USDA guidance specifies additional management expectations for vermicompost used in organic production.

3. Compost livestock manure and bedding

Livestock manure and used bedding can be valuable fertility resources because they recycle nutrients already present on the farm. Their nutrient content varies widely with animal species, diet, bedding, storage, and moisture, so a manure analysis is the best basis for an application rate.

Store manure away from wells, surface water, drainageways, and produce handling areas. Composting can stabilize the material, reduce odors and weed seeds, and lower pathogen risk when the process is managed correctly.

Do not assume that old or stockpiled manure is compost. Aged manure that has not gone through a validated composting process may still be treated as raw manure under organic rules.

For certified organic food crops, USDA rules require raw manure to be incorporated at least 120 days before harvest when the edible portion may contact soil or soil particles, and at least 90 days before harvest for other food crops. Other operations should follow applicable federal, state, local, buyer, and food-safety requirements.

4. Grow cover crops and green manure

Cover crops can produce fertility in place while protecting soil from erosion. Legumes such as clover, vetch, field peas, and cowpeas can fix atmospheric nitrogen when they are properly inoculated and growing well. Grasses such as cereal rye or oats capture leftover nutrients and produce carbon-rich biomass. Mixed stands can provide both benefits.

Terminate the cover crop at the appropriate stage and allow time for residue to decompose before planting the cash crop. The amount of nitrogen released depends on species, biomass, maturity, weather, soil conditions, and how the residue is managed. Use regional Extension guidance or a cover-crop calculator to estimate a nitrogen credit rather than assuming the crop will supply the entire requirement.

5. Use tested plant-based amendments

Clean plant residues can be composted, surface-applied as mulch, or grown as green manure. Some operations also use approved meals or mineral amendments, but these are best selected from a soil test and a product's guaranteed analysis-not from a one-size-fits-all recipe.

If you are certified organic, verify every purchased input with your certifier before use. "Natural" does not automatically mean allowed, safe, or appropriate for a particular field.

As an added bonus, here is a fertilizer calculator to find the ratios you need.

Can you make liquid fertilizer or compost tea?

Water extracts nutrients from compost, vermicompost, and plant material, but the resulting liquid is not automatically a complete or predictable fertilizer. Its nutrient concentration can vary significantly, and homemade liquids can create food-safety concerns when they contain manure, animal products, added sugars, or poorly finished compost.

If you use a compost extract, apply it to the soil, start with mature compost, keep equipment clean, and avoid spraying edible plant parts. Certified organic growers should verify their materials and process with their certifier. For dependable crop nutrition, use laboratory results and a calculated fertility plan rather than relying on an untested "tea."

How to calculate an application rate

You need two pieces of information:

• The crop's nutrient requirement from a soil test or regional production guide.

• The nutrient analysis and estimated first-year availability of the amendment.

A simplified calculation for the amound of amendment needed is:

nutrient required ÷ plant-available nutrient supplied per unit of amendment

Not all nutrients in compost or manure become available during the first season. Availability depends on the material, soil, temperature, moisture, and application method. A laboratory or Extension specialist can help translate an analysis into a safe field rate.

Calibrate your spreader or applicator, measure the treated area, and record the material, analysis, rate, date, field, crop, and weather conditions. Do not apply when soil is frozen, saturated, flooded, or vulnerable to runoff, and follow all local nutrient-management rules.

Homemade fertilizer mistakes to avoid

• Skipping the soil test. Symptoms that look like a nutrient deficiency may be caused by pH, root damage, compaction, drought, disease, or excess nutrients.

• Following generic chemical recipes. Do not attempt to manufacture ammonium sulfate, superphosphate, or other chemical fertilizers on the farm. Industrial production uses controlled processes and hazardous materials.

• Applying raw manure close to harvest. This can expose edible crops to human pathogens and may violate organic, food-safety, or buyer requirements.

• Using human or pet waste. These materials can introduce pathogens, pharmaceuticals, or other contaminants and should not be used in ordinary food-crop compost.

• Assuming homemade inputs are balanced. Compost, manure, and plant extracts vary. Test when possible and account for every nutrient source.

• Using contaminated feedstocks. Persistent herbicides, treated wood, plastics, diseased material, and unknown industrial wastes do not belong in farm compost.

• Adding lime without a pH recommendation. Lime changes soil chemistry; unnecessary use can make micronutrients less available.

• Overapplying compost. Repeated heavy applications can build excessive phosphorus, potassium, salts, or organic matter.

A simple on-farm fertility workflow

1. Test each management area and identify crop nutrient needs.

2. Inventory compost, manure, bedding, crop residues, and cover-crop opportunities.

3. Test nutrient-rich amendments and check input eligibility if certified organic.

4. Choose the amendment or combination that meets the limiting need with the fewest excess nutrients.

5. Calculate and calibrate the application rate.

6. Apply under suitable soil and weather conditions.

7. Record the application and observe crop performance.

8. Retest soil and adjust the plan for the next season.

Growing the healthiest plants depends on the nutrients they need

Making sure you're plants have the right level of nutrients will ensure a healthy crop. When you're growing crops or gardening, the work doesn't stop at planting. Making your own fertilizer on-farm is an easy way to save money, reduce waste, and customize nutrients to your plants’ needs. It is a great way to recycle used livestock bedding and manure, as well.

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Frequently Asked Questions (FAQs)

What is the easiest homemade fertilizer to make?

Finished plant-based compost is usually the easiest and safest option. Combine carbon-rich and nitrogen-rich materials, manage moisture and airflow, allow the pile to finish and cure, then apply it according to soil-test results. Its main benefits are organic matter and slow nutrient release rather than a precise N-P-K dose.

Can compost replace fertilizer?

Sometimes, but not always. Compost can supply nutrients and improve soil, yet it may release too little nitrogen for a demanding crop or supply too much phosphorus when used at a nitrogen-based rate. Compare a compost analysis with the crop recommendation before deciding whether another nutrient source is needed.

Is manure a fertilizer?

Yes. Manure contains nitrogen, phosphorus, potassium, organic matter, and micronutrients, but its composition is variable. Test it, credit its nutrients in the fertility plan, and follow storage, application, food-safety, and organic-certification requirements.

Can I put fresh manure directly on vegetable crops?

Avoid applying raw manure to growing vegetables or close to harvest because it may contain human pathogens. Certified organic farms must observe USDA's 90- or 120-day intervals between raw-manure incorporation and harvest, depending on whether the edible crop portion contacts soil. Other food-safety or buyer requirements may also apply.

Are coffee grounds, eggshells, and banana peels good fertilizer?

They contain plant nutrients, but they are not balanced, fast-acting fertilizers. Compost them first instead of applying large amounts directly. Eggshells break down slowly, coffee grounds can mat when used heavily, and banana peels do not provide a predictable potassium dose.

Should I make fertilizer from urine?

Human urine can contain nutrients, but using it on food crops raises sanitation, storage, dosing, regulatory, and certification questions. It is not a good default recommendation for farms or edible gardens. Use tested and permitted nutrient sources, and consult local authorities and your organic certifier before considering any human-waste-derived material.

How often should I test my soil?

Testing every two to three years is common for stable fields, while intensively managed vegetable beds, high tunnels, or problem areas may need annual testing. Sample at the same time of year and use the same laboratory when possible so results are easier to compare.

Is homemade fertilizer allowed in certified organic production?

It can be, but every feedstock, production method, and application must comply with the operation's Organic System Plan and USDA organic regulations. Check with your certifier before producing or applying a new input.

Resources

• USDA Agricultural Marketing Service: Compost and Vermicompost in Organic Crop Production

• USDA Agricultural Marketing Service: Soil Building-Manures and Composts

• University of Minnesota Extension: Manure Sampling and Nutrient Analysis

• University of Minnesota Extension: Correcting Problems Caused by Too Much Compost and Manure