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Organic fertilizers are a game-changer for gardeners looking to achieve healthy, nutrient-rich soil and vibrant plant growth. In “The Ultimate Guide to Organic Fertilizers,” you’ll uncover a treasure trove of knowledge on how these natural substances can revolutionize your gardening experience. From understanding the benefits of organic fertilizers to a comprehensive breakdown of the various types available, this guide will equip you with the tools you need to maximize your garden’s potential while minimizing your environmental impact. Get ready to unlock the secrets of organic fertilizers and take your gardening skills to the next level.

The Ultimate Guide To Organic Fertilizers

Table of Contents

What Are Organic Fertilizers?

Definition of Organic Fertilizers

Organic fertilizers are natural substances that are derived from living organisms or their by-products. These fertilizers are used to provide essential nutrients to plants and enhance soil health, without the use of synthetic chemicals. They are made from organic matter such as animal manure, compost, bone meal, fish emulsion, seaweed, and plant-based materials.

Difference Between Organic and Synthetic Fertilizers

The main difference between organic and synthetic fertilizers lies in their composition and mode of action. Organic fertilizers are derived from natural sources and release nutrients slowly over time as the organic matter breaks down. This slow-release nature ensures that the nutrients are available to plants as they need them, reducing the risk of nutrient leaching and plant burn. On the other hand, synthetic fertilizers are chemically manufactured and generally provide nutrients in a readily available form. While synthetic fertilizers can provide a quick nutrient boost to plants, they may also result in nutrient runoff and can harm beneficial soil organisms.

Types of Organic Fertilizers

There are various types of organic fertilizers available, each with its own set of benefits and nutrient profiles. Some common types of organic fertilizers include:


Compost is created by decomposing organic materials such as kitchen scraps, yard waste, and plant trimmings. It is rich in organic matter and nutrients, making it an excellent all-purpose fertilizer.


Animal manure, such as cow, horse, or chicken manure, is a valuable source of nitrogen, phosphorus, and potassium. It improves soil structure and fertility when properly composted or aged.

Bone Meal

Bone meal is made from ground animal bones and is a good source of phosphorus and calcium. It helps promote root development and overall plant growth.

Fish Emulsion

Fish emulsion is a nutrient-rich liquid fertilizer made from fermented fish remains. It provides a source of nitrogen, phosphorus, and micronutrients, and is particularly beneficial for promoting healthy foliage growth.

Seaweed and Kelp

Seaweed and kelp are organic fertilizers sourced from marine plants. They are rich in trace minerals, growth hormones, and natural plant nutrients. They stimulate root growth, improve soil structure, and enhance overall plant health.

Green Manure

Green manure is created by growing cover crops, such as clover or vetch, and then incorporating them into the soil. This practice helps to increase organic matter, improve soil fertility, and suppress weeds.

Blood Meal

Blood meal is made from dried animal blood and is a potent source of nitrogen. It is particularly useful for promoting vigorous growth in nitrogen-hungry plants.

Feather Meal

Feather meal is produced from sterilized poultry feathers and is a slow-release source of nitrogen. It breaks down gradually, providing a sustained nutrient supply to plants over time.

Cottonseed Meal

Cottonseed meal is a by-product of the cottonseed oil extraction process. It is an excellent source of nitrogen, phosphorus, and potassium. It improves soil fertility and promotes healthy plant growth.

Rock Phosphate

Rock phosphate is a natural mineral rock that is high in phosphorus. It is slowly released into the soil, providing a long-lasting source of this essential nutrient.

Benefits of Using Organic Fertilizers

Improves Soil Structure and Fertility

One of the key benefits of using organic fertilizers is their ability to enhance soil structure and fertility. Organic matter in fertilizers improves soil texture, allowing for better water retention and aeration. It also encourages the development of beneficial microorganisms that break down organic matter and release nutrients, further improving soil fertility.

Enhances Nutrient Availability

Organic fertilizers provide a gradual and sustained release of nutrients, ensuring a steady supply for plant uptake. Unlike synthetic fertilizers that can cause nutrient imbalances and leaching, organic fertilizers release nutrients slowly and in a more balanced manner, reducing the risk of nutrient loss and plant stress.

Promotes Beneficial Microorganisms

Organic fertilizers create a favorable environment for beneficial microorganisms to thrive. These microorganisms break down organic matter, releasing nutrients and improving soil health. They also help suppress harmful pathogens and diseases, promoting a healthier and more resilient soil ecosystem.

Reduces Environmental Impact

Unlike synthetic fertilizers, organic fertilizers have minimal negative environmental impact. They do not contribute to chemical runoff and water pollution, making them a more sustainable choice for gardeners. Organic fertilizers also support biodiversity by nurturing a diverse and robust soil microbiome.

Safe for Humans and Pets

Organic fertilizers are safe to use around humans and pets. They do not contain harmful chemicals or synthetic additives that could pose a risk to their health. This makes organic fertilizers an ideal choice for households with children, pets, or those who prioritize environmentally friendly practices.

Common Organic Fertilizers


Compost is created through the natural decomposition of organic materials, such as kitchen scraps, yard waste, and plant trimmings. It is a nutrient-rich soil amendment that improves soil structure, provides slow-release nutrients, and enhances microbial activity. Compost can be made at home or purchased from garden centers and is suitable for a wide range of plants and garden applications.


Animal manure, such as cow, horse, or chicken manure, is a popular organic fertilizer rich in nutrients. However, it is essential to compost or age manure properly before using it on plants. This process helps eliminate any potential pathogens or weed seeds and makes the nutrients more readily available to plants. Manure can be sourced from local farms or purchased as bagged composted manure from garden centers.

Bone Meal

Bone meal is made from ground animal bones and is a valuable source of phosphorus and calcium. It promotes strong root development, aids in flower and fruit formation, and helps plants withstand environmental stress. Bone meal is often used to fertilize bulbs, roses, and fruit-bearing plants.

Fish Emulsion

Fish emulsion is a liquid fertilizer made from fermented fish remains. It is a rich source of nitrogen, phosphorus, and micronutrients. Fish emulsion is especially useful for promoting healthy foliage growth and is commonly used on leafy greens, herbs, and container plants.

Seaweed and Kelp

Seaweed and kelp are derived from marine plants and are packed with essential nutrients, trace minerals, and growth hormones. They help improve soil structure, stimulate root growth, enhance nutrient uptake, and improve overall plant health. Seaweed and kelp extracts can be applied as foliar sprays or used as soil drenches.

Green Manure

Green manure is created by growing cover crops, such as clover, vetch, or rye, and then incorporating them into the soil. This practice adds organic matter and nutrients, improves soil structure, and suppresses weeds. Green manure crops are typically planted during fallow periods or as a winter cover crop.

Blood Meal

Blood meal is a high-nitrogen fertilizer made from dried animal blood. It is an excellent choice for promoting vigorous growth in nitrogen-loving plants such as leafy greens, corn, and tomatoes. Blood meal should be used sparingly as it can burn plants if over-applied.

Feather Meal

Feather meal is made from sterilized poultry feathers and is a slow-release source of nitrogen. It breaks down gradually, providing a sustained nutrient supply to plants over an extended period. Feather meal is often used as a nitrogen booster for plants that require long-term nutrient availability.

Cottonseed Meal

Cottonseed meal is a by-product of the cottonseed oil extraction process. It is an excellent organic fertilizer that provides a well-balanced mix of nitrogen, phosphorus, and potassium. Cottonseed meal improves soil fertility, promotes healthy foliage growth, and is commonly used in vegetable gardens and flower beds.

Rock Phosphate

Rock phosphate is a natural mineral rock that contains high levels of phosphorus. It is a slow-release fertilizer, meaning it takes time to break down and release its nutrients into the soil. Rock phosphate is particularly beneficial for plants with high phosphorus requirements, such as root crops and flowering plants.

Choosing the Right Organic Fertilizer

Understanding Nutrient Requirements

Before choosing an organic fertilizer, it is important to understand the nutrient requirements of your specific plants. Different plants have different nutritional needs, and using the right fertilizer can help meet those needs effectively. A soil test or plant nutrient analysis can provide valuable information about nutrient deficiencies and guide you in selecting the appropriate organic fertilizer.

Soil Testing

Conducting a soil test is an essential step in determining the nutrient composition and pH level of your soil. It provides valuable information about the soil’s fertility and helps identify any nutrient imbalances or deficiencies. Soil testing kits are readily available for home gardeners, or you can send a soil sample to a laboratory for professional analysis. Knowing the current state of your soil will help you make informed decisions about fertilizing and amending the soil.

Matching Fertilizer to Plant Needs

Different plants have different nutrient requirements at different stages of growth. It is essential to match the fertilizer’s nutrient composition to the specific needs of your plants. For example, leafy vegetables benefit from nitrogen-rich fertilizers, while phosphorus is crucial for promoting flowering and fruiting in fruit-bearing plants. Understanding the nutritional requirements at different growth stages will help you select the most suitable organic fertilizer.

Considering Release Rates

Organic fertilizers release their nutrients at different rates, depending on their composition and formulation. Some fertilizers release nutrients slowly over an extended period, while others provide a quick-release of nutrients. Consider the growth requirements of your plants and choose a fertilizer with a release rate that aligns with their needs. Slow-release fertilizers are particularly beneficial for maintaining a steady nutrient supply and minimizing the risk of nutrient runoff.

Balancing N-P-K Ratios

Nitrogen (N), phosphorus (P), and potassium (K) are the primary macronutrients required by plants. The ratio of these nutrients, known as the N-P-K ratio, indicates the fertilizer’s composition. Different plants have varying nutrient requirements, and it is important to select an organic fertilizer with an appropriate N-P-K ratio. For example, leafy greens benefit from a higher nitrogen content, while flowering plants require more phosphorus. Understanding the nutrient needs of your plants will help you choose a fertilizer that provides the right balance of nutrients.

Avoiding Excessive Salt Content

Some organic fertilizers, such as seaweed or fish-based fertilizers, may contain a high salt content. Excessive salt can negatively impact plant growth and lead to soil degradation. When selecting organic fertilizers, be mindful of their salt content and use them in moderation, especially in sensitive plants or areas with limited rainfall. It is also important to flush the soil with water periodically to prevent salt buildup and ensure optimal plant health.

The Ultimate Guide To Organic Fertilizers

How to Apply Organic Fertilizers

Surface Application

Surface application involves spreading the organic fertilizer evenly on the soil surface around the base of the plants. This method is suitable for established plants and can be done by hand or with a garden rake. Make sure to spread the fertilizer several inches away from the plant stems to avoid burning the delicate root system.

Incorporation into Soil

For better nutrient distribution and availability, organic fertilizers can be incorporated into the soil. Dig a shallow trench or furrow around the plants and distribute the fertilizer evenly. Lightly cover the fertilizer with soil, being careful not to damage the plant roots. Water thoroughly after incorporating the fertilizer to help it dissolve and reach the plant roots.

Foliar Feeding

Foliar feeding involves applying a diluted organic fertilizer directly to the leaves of plants. This method provides a quick nutrient boost and is particularly useful for correcting nutrient deficiencies or overcoming poor soil conditions. Dilute the organic fertilizer according to the manufacturer’s instructions and spray it onto the foliage, ensuring complete coverage. Do foliar feeding early in the day to allow the foliage to dry before nighttime, reducing the risk of fungal infections.

Using Fertilizer Spikes or Granules

Fertilizer spikes or granules are convenient and easy-to-use forms of organic fertilizers. They can be directly inserted into the soil around the plant’s drip line. The spikes or granules release nutrients gradually as they dissolve, providing a continuous nutrient supply to the plants. Follow the manufacturer’s instructions on the packaging for proper placement and spacing.

Watering in the Fertilizer

Watering is an important step after applying organic fertilizers. This helps dissolve the nutrients and carry them down to the plant roots. Watering also prevents the fertilizer from being washed away or remaining on the foliage, which can cause damage. Ensure thorough watering to allow the organic fertilizer to penetrate deep into the soil and reach the plant’s root zone.

Frequency and Timing of Applications

The frequency and timing of organic fertilizer applications depend on the specific plant’s nutritional requirements and growth cycle. In general, fertilizing should be done during the active growing season of plants. Some plants may require multiple applications throughout the growing season, while others may only need fertilizer at the beginning or end of the season. Always follow the fertilizer manufacturer’s instructions and consider the specific needs of your plants.

Avoiding Over-Fertilization

Over-fertilization can harm plants and result in nutrient imbalances. It is important to use organic fertilizers in moderation and follow the recommended application rates. More is not always better, and excessive use of organic fertilizers can lead to nutrient runoff, leaching, or burned foliage. Monitor your plants for any signs of over-fertilization, such as leaf burn or stunted growth, and adjust your fertilization practices accordingly.

Making Your Own Organic Fertilizers

Composting Techniques

Composting is a simple and effective way to create your own organic fertilizer. Start by collecting kitchen scraps, yard waste, and other organic materials such as coffee grounds, eggshells, and grass clippings. Layer these materials in a compost bin or pile, ensuring a proper balance of greens (nitrogen-rich materials) and browns (carbon-rich materials). Turn the compost regularly to promote decomposition, and within a few months, you will have nutrient-rich compost ready for use in your garden.


Vermicomposting involves using worms to break down organic waste into nutrient-rich vermicompost. You can set up a vermicomposting bin in your home or garden by adding bedding materials such as shredded newspaper or coconut coir, along with kitchen scraps. Add redworms (Eisenia fetida) to the bin, and they will process the organic waste into valuable vermicompost. Harvest the vermicompost when it is dark, crumbly, and free of worms, and use it to fertilize your plants.

Manure Tea

Manure tea is a liquid fertilizer made by steeping composted manure in water. Fill a large container with water, add composted manure (such as composted cow or horse manure) in a mesh bag or old pillowcase, and let it steep for several days. Stir the mixture occasionally to ensure thorough soaking. Once the tea is ready, dilute it with water (1:10 ratio), and use it as a nutritional boost for your plants.

Bone Meal Preparation

Creating bone meal at home involves grinding up animal bones into a fine powder or purchasing bone meal from a trusted source. If making bone meal, thoroughly clean and dry the bones before grinding them. You can use a mortar and pestle, blender, or food processor to grind the bones into a powder. Ensure the bone meal is finely ground to maximize nutrient availability. Use bone meal to provide phosphorus and calcium to plants, especially those that require strong root development and flowering.

Seaweed or Kelp Extract

To make your own seaweed or kelp extract, collect fresh seaweed or kelp from the beach or purchase dried seaweed or kelp. If using fresh seaweed or kelp, rinse off any saltwater and chop it into small pieces. Place the seaweed or kelp in a bucket, cover it with water, and let it soak for a few days. Stir the mixture occasionally to ensure even extraction. Strain the liquid to remove any solid particles, and use the seaweed or kelp extract as a foliar spray or soil drench to promote plant growth and overall health.

DIY Organic Liquid Fertilizers

In addition to the methods mentioned above, there are several other DIY organic liquid fertilizers you can make at home. For example, you can create nettle tea by steeping nettle leaves in water, or banana peel tea by soaking banana peels in water. These homemade fertilizers provide additional nutrients and minerals to your plants, promoting healthy growth and productivity.

Supplementing Organic Fertilizers

Adding Beneficial Bacteria and Fungi

Supplementing organic fertilizers with beneficial bacteria and fungi can further enhance soil health and plant growth. Beneficial soil microorganisms, such as mycorrhizal fungi and nitrogen-fixing bacteria, form symbiotic relationships with plant roots, aiding in nutrient uptake and overall plant health. These microorganisms can be introduced to the soil through inoculants or by incorporating well-aged compost or vermicompost.

Using Organic Amendments

Organic amendments, such as biochar, humic acid, and organic matter, can be used in conjunction with organic fertilizers to improve soil structure and nutrient availability. These amendments help increase water-holding capacity, enhance microbial activity, and promote nutrient retention in the soil. Organic amendments should be mixed into the soil during planting or applied as topdressing around established plants.


Mulching is an effective way to conserve moisture, suppress weeds, and add organic matter to the soil. Organic mulches, such as straw, wood chips, or compost, provide additional nutrients as they break down. Apply a layer of mulch around the base of plants, being careful not to bury the stems, to help retain moisture and improve soil fertility.

Crop Rotation

Crop rotation involves systematically planting different crops in the same space over multiple growing seasons. This practice helps improve soil health and fertility by preventing the buildup of pests, diseases, and nutrient imbalances. By rotating crops, you can maximize the effectiveness of organic fertilizers and minimize the need for synthetic inputs.


Intercropping involves planting different crops together in the same area. This practice promotes biodiversity, enhances pest control, and optimizes nutrient utilization. Planting nitrogen-fixing crops, such as legumes, alongside other plants can provide a natural source of nitrogen to neighboring plants. Intercropping also maximizes space and allows for efficient utilization of organic fertilizers.

Cover Cropping

Cover cropping, also known as green manure, involves planting cover crops during fallow periods or as a winter cover. These crops help protect and improve the soil by adding organic matter, suppressing weeds, preventing erosion, and fixing nitrogen. Cover crops can be grown specifically to accumulate nutrients in their tissues, which can then be incorporated into the soil as a natural source of organic fertilizer.

Storing and Handling Organic Fertilizers

Proper Packaging and Labeling

When purchasing organic fertilizers, ensure they are properly packaged and labeled. The packaging should be sturdy, sealed, and clearly labeled with the product’s name, ingredients, and instructions for use. Proper packaging and labeling ensure that the fertilizer remains fresh and effective until it is ready to be used.

Avoiding Moisture and Heat Exposure

Organic fertilizers should be stored in a cool, dry place to maintain their quality and prevent moisture absorption or mold growth. Excessive heat and humidity can degrade the nutrients in organic fertilizers, rendering them less effective. It is best to store fertilizers in airtight containers or resealable bags to protect them from environmental conditions.

Storing in a Cool and Dry Place

Store organic fertilizers in a cool and dry place, away from direct sunlight and extreme temperature fluctuations. An ideal storage location is a shed or garage that is well-ventilated and can maintain a consistent temperature and humidity. Storing fertilizers away from children and pets is also important for their safety.

Preventing Contamination

To prevent contamination, it is important to keep organic fertilizers separate from other chemicals, pesticides, or household cleaning agents. Cross-contamination can occur if fertilizers come into contact with these substances, rendering them unfit for use. Always handle organic fertilizers with clean hands or gloves and avoid introducing foreign materials into the product.

Safety Precautions

While organic fertilizers are generally safe to use, it is essential to follow basic safety precautions. Wear protective gloves and a mask when handling fertilizers, especially in concentrated forms. Avoid inhaling dust or fumes from dry fertilizers and wash your hands thoroughly after handling them. If using liquid fertilizers, follow the manufacturer’s instructions on safe handling and storage.

Proper Disposal Methods

When disposing of unused or expired organic fertilizers, it is important to follow proper disposal methods. Do not dump fertilizers down drains or directly into water sources, as they can contribute to water pollution. Instead, contact your local waste management or recycling center for guidance on the proper disposal of organic fertilizers. Many communities offer programs to collect and recycle unused fertilizers.

Common Misconceptions About Organic Fertilizers

Organic Means Slow-Acting

While organic fertilizers may release nutrients more slowly than synthetic fertilizers, they can still provide timely nutrition to plants. Depending on the specific formulation, organic fertilizers can offer medium to fast nutrient availability. Additionally, the slow-release nature of organic fertilizers helps prevent nutrient leaching and ensures a more sustained supply of nutrients to plants.

Organic Fertilizers Are Always Safe

While organic fertilizers are generally considered safe, it is still important to handle and use them responsibly. Some organic fertilizers can pose a risk if ingested or inhaled in large quantities. Additionally, improper storage or handling of organic fertilizers can lead to contamination or accidental exposure. Always follow safety guidelines, use protective equipment when necessary, and keep fertilizers out of reach of children and pets.

Organic Fertilizers Are Always Better

While organic fertilizers have numerous benefits, they may not always be the best choice for every situation. The efficacy of organic fertilizers depends on various factors, including soil composition, plant nutrient requirements, and specific gardening goals. Sometimes, a combination of organic and synthetic fertilizers may be more suitable to meet specific nutrient needs or address specific gardening challenges.

Organic Fertilizers Are More Expensive

Although organic fertilizers can sometimes be more expensive upfront compared to synthetic fertilizers, they can offer long-term savings and added value to the garden. Organic fertilizers improve soil health, reduce the need for synthetic inputs, and promote sustainable gardening practices. Over time, the improved soil fertility and reduced environmental impact can offset the initial cost of organic fertilizers.

Organic Fertilizers Cannot Burn Plants

While organic fertilizers are generally less likely to cause plant burn compared to synthetic fertilizers, it is still possible to over-fertilize with organics and cause harm to plants. Organic fertilizers, especially those high in nitrogen, can burn plants if applied in excessive amounts or in concentrated form. Always follow the recommended application rates and take into account the specific needs of your plants.

Organic Fertilizers Provide Everything Plants Need

While organic fertilizers contribute to overall plant health and supply essential nutrients, they may not provide all the nutrients plants require in optimal amounts. Depending on the soil composition and specific plant needs, additional nutrient supplementation may be necessary. Regular soil testing, plant observation, and a balanced approach to fertilization can help ensure that plants receive all the necessary nutrients for optimal growth.


Choosing organic fertilizers for your gardening needs is a sustainable and environmentally friendly choice. Organic fertilizers enhance soil structure and fertility, promote beneficial microorganisms, and reduce environmental impact. They provide a slow release of nutrients, ensuring balanced nutrition for plants and minimizing the risk of nutrient runoff. Organic fertilizers are safe for humans and pets, making them an ideal option for households with children or pets.

Common organic fertilizers, such as compost, manure, bone meal, fish emulsion, and seaweed, offer a wide range of nutrients to meet plant needs. By understanding nutrient requirements, performing soil tests, and balancing N-P-K ratios, you can select the appropriate organic fertilizer for your plants. Proper application methods, such as surface application, incorporation into the soil, foliar feeding, or using fertilizer spikes, ensure effective nutrient uptake and minimize wastage.

Making your own organic fertilizers through composting, vermicomposting, manure tea, bone meal preparation, and seaweed or kelp extracts provides an opportunity to recycle organic waste and create valuable soil amendments. Supplementing organic fertilizers with beneficial bacteria and fungi, using organic amendments, mulching, crop rotation, intercropping, and cover cropping further enhance soil health and optimize plant growth.

When storing and handling organic fertilizers, proper packaging, labeling, and storage conditions should be observed to maintain the fertilizers’ effectiveness and prevent contamination. Following safety precautions and disposing of organic fertilizers correctly are essential for minimizing any potential risks.

Lastly, it is important to address common misconceptions about organic fertilizers. While they are generally safe and environmentally friendly, organic fertilizers are not always slow-acting, may not be the best choice for every situation, and can cause plant burn if misused. Organic fertilizers should be seen as a complementary tool to maintain soil health, support plant growth, and promote sustainable gardening practices. By finding the right balance and considering the specific needs of your plants and garden, organic fertilizers can provide numerous benefits for both the environment and plant health.

This post may contain affiliate links which means I may receive a commission for purchases made through links.  Learn more on my Private Policy page.