Guide to Organic Fertilizer: Types and How to Use in Your Garden

Jul 24th 2025

Organic fertilizers are leading the way in organic gardening by supplying essential nutrients to plants, allowing gardeners to have a fulfilling experience. Gardeners and farmers are increasingly opting for organic fertilizers over synthetic ones because they are more beneficial for plants, soil, humans, and the environment. Artificial fertilizers are made using industrial chemicals, whereas organic fertilizers are derived from natural sources and are designed to enhance soil fertility, nourish plants, and gently improve the environment. Fertilizing your garden with a high-quality natural fertilizer is essential for growing lush, healthy plants. If you're looking for a natural fertilizer that is best for your plants, you need to look beyond traditional synthetic fertilizer options.

Check out our comprehensive guide to organic fertilizers and discover the best types of organic fertilizers, how to use them efficiently, and how they can work for your garden now and in the future.

Why Choose Organic Fertilizers for Your Garden

Organic fertilizers are made from natural animal and plant materials, as well as mined rock minerals. They don't contain any chemicals or harmful materials. In contrast to manufactured fertilizers, which are produced through chemical processes, organic fertilizers slowly break down and release their nutrients into the soil over time. This slower release is like the natural nutrient cycle in the soil, so it is less likely to harm plants or cause nutritional problems. By using organic fertilizers such as Archipelago Natural Fertilizer, you can rest assured that your yard and garden are safe and healthy.

Here are the benefits of organic fertilizers that prove they are a good choice over synthetic ones.

Safe for Everyone: Synthetic fertilizers might contain harmful chemicals, whereas organic fertilizers don't contain any, so they are safe for pets, kids, and local wildlife.

Environmentally Friendly: Organic fertilizers release nutrients slowly, allowing plants to absorb them, and thereby lowering the risk of water pollution and runoff. However, synthetic fertilizers contain chemicals that contaminate water systems and damage aquatic life.

Sustainable and Cost-effective: Although synthetic fertilizers may provide an instant nutrient boost, they need to be applied frequently. Organic fertilizers, on the other hand, boost soil health over time, so you'll need to use them less often. Additionally, many organic fertilizers can be made at home using yard waste or food scraps, making them a budget-friendly and waste-reducing option.

Supports Soil Health: Organic fertilizers nourish the soil and plants. They build up organic matter, improve soil structure, promote a thriving soil ecosystem, and help the soil retain water.

Promotes Better Plant Health: Organic fertilizers promote consistent, balanced growth, resulting in stronger, healthier plants.

Best Types of Organic Fertilizers

There are multiple types of organic fertilizers available to choose from. Different organic fertilizers add different nutrients to the soil. The fertilizer and nutrients you need depend on your garden soil and the plants you are growing.

Check out our list of different types of organic fertilizers and find out what is suitable for your garden's needs.

Plant-based Fertilizers

Plant-based fertilizers decompose more quickly than other organic materials, but they provide more soil conditioning than actual nutrients. These materials, such as compost or alfalfa meal, help to improve drainage and moisture retention in poor soils.

Let's look at different plant-based organic fertilizers.

Compost

Compost is sometimes known as "black gold" due to its high nutrient value, like California Gold Fertilizer. It is made from broken-down organic materials, including yard waste, kitchen scraps, and culinary leftovers. This is an all-purpose organic fertilizer, rich in nutrients and beneficial microorganisms. Moreover, beneficial bacteria grow in compost, which helps in the breakdown of organic matter in the soil and increases the availability of nutrients to plants.

Alfalfa Meal

Alfalfa meal is an excellent, inexpensive organic fertilizer that mimics nature when applied. Its nutrient content contains a large amount of nitrogen and potassium. It is an excellent early spring fertilizer to prepare your soil for planting. Alfalfa is a common cover crop in vegetable gardens that nourishes the soil with nutrients. So, even if you don't plant cover crops regularly, you can still receive the benefits.

Cottonseed Meal

Cottonseed meal is a great plant-based organic fertilizer that has no animal byproducts. It is a byproduct of the cottonseed oil process that enriches soil with around 6% nitrogen, as well as some phosphorus and potassium. It can also serve as a weed suppressor. If you add this plant feed to your garden bed in the fall, the nutrients will be available to your plants in the coming spring.

Animal-based Fertilizers

Animal-based fertilizers, such as bone meal, manure, insect frass, and blood meal, add large amounts of nitrogen to the soil. These products add more nitrogen to the soil than plant-based materials. They're ideal for growing leafy crops and corn. Cow manure is the preferred natural plant fertilizer due to its well-balanced nutritional composition.

Here we look at different types of animal-based organic fertilizers, including:

Manure

Manure, also known as animal waste, is a nutrient-dense fertilizer for gardens that has been used for decades. Cows, chickens, and horses produce manure. Every type of animal manure has a unique nutrient profile, so use one that meets the needs of your garden. Also, ensure the manure is aged or well-decomposed, as fresh manure can burn plants during the decomposition process.

Fish Fertilizer

Fish fertilizer is another fast-acting natural fertilizer that adds valuable nutrients to the soil, improving soil fertility and health organically. Healthy soil encourages the growth and health of plants. Fish fertilizer is an excellent source of macronutrients like nitrogen, potassium, and phosphorus as well as micronutrients like calcium, magnesium, sulfur, chlorine, and sodium. It is an all-purpose feeding option that can be used as a foliar spray, soil fertilizing additive, or added to your compost pile.

Worm Castings

Worm castings, also known as worm manure, are excellent, readily available organic fertilizers. Worms eat and release water-soluble nutrients, making them immediately available to plants. Worm castings fertilizers are easy to apply and can significantly improve your soil health. Mix it into potting soil or sprinkle it on top of the soil around plants. This fertilizer is perfect for potted plants and seedlings because it is mild and does not burn the roots.

Blood Meal

Blood meal is simply dried animal blood, which is a byproduct of slaughterhouses. It is a water-soluble fertilizer that can be used as a liquid. Blood meal is a rich source of nitrogen, promoting healthy foliage development. Its addition to soil significantly boosts nitrogen levels. Nitrogen levels in soils fluctuate often because many plants are heavy nitrogen feeders. This is beneficial if your garden beds are used every year and are prone to nutrient depletion.

Bone meal is perfect for feeding vegetables that are heavy feeders of nitrogen. These plants include cucumbers, tomatoes, peppers, squash, asparagus, corn, broccoli, eggplant, and okra.

Bone Meal

Bone meal is a natural soil amendment made up of steamed and finely crushed animal bones. High in calcium and phosphorus, it is excellent for strong root development, disease prevention, and flowering. Bone meal also contains essential micronutrients such as iron, zinc, and magnesium that enhance plant health and benefit soil microbial growth. This fertilizer comes in both powdered and granular formulas and won't burn your plants if you happen to overuse it. Use this organic fertilizer when planting vegetables, bulbs, and perennials to promote strong root systems and colorful blooms.

Mineral-based Organic Fertilizers

Mineral-based fertilizers are made from naturally occurring minerals. The slow-release quality of these fertilizers is a significant benefit, as it provides a consistent supply of nutrients to plants over an extended period. This enhances the nutrient absorption process in plants while reducing the risk of nutrient loss. Also, organic fertilizers made of natural minerals improve soil texture and moisture retention and encourage the growth of beneficial microorganisms.

The most common mineral-based organic fertilizers include:

Greensand

It is an excellent source of potassium, both as a standalone soil amendment and as an additive to fertilizing mixtures.

Limestone

It contains high calcium carbonate content, which helps increase soil fertility by improving its chemical properties and reducing acidity.

Rock Phosphate

Also known as phosphorite, rock phosphate is an economical mineral-based organic fertilizer. It is a natural source of slowly releasing soluble phosphorus.

Epsom Salt

Epsom salt is a natural mineral salt that contains high levels of magnesium, sulfur, and oxygen. It is highly soluble in water and quickly releases magnesium and sulfur, two key nutrients essential for healthy plant growth. Epsom salt is ideal for plants that require an extra boost of magnesium. These can include roses, tomatoes, peppers, and container-grown plants.

For using Epsom salts for plants, first, you need to dilute the salts in water. The general rule is to add two tablespoons (30 mL) of salts per gallon (3.8 L) of water and only apply one or two times per month.

When and How to Use Organic Fertilizer in Your Garden

Before adding any soil amendments or fertilizers to your garden, have a garden soil test done to determine the pH of your soil and any nutrients that it may be lacking. Once you obtain soil test results, use the recommended organic fertilizers from this guide before planting and throughout the growing season to promote steady growth and maintain healthy soil and plants.

You should choose the fertilizer based on soil test results and plant needs, in terms of nutrient content and speed of delivery. Other crucial factors to consider are soil health and your budget.

How to apply fertilizers to your plants?

Fertilizer application techniques include:

Incorporating Fertilizer: Mixing fertilizers into the soil before planting.

Side-Dressing Fertilizer: Applying fertilizer alongside plant rows during the growing season. This delivers nutrients directly to the plant when demand is high. It's useful for crops with high nutritional requirements during specific growth stages in their life cycle.

Broadcasting: Spreading dry or granular fertilizer evenly over the soil surface. This approach is simple and best for large-scale farming. Ensure you use the correct equipment for even distribution. Calibration of fertilizer spreaders is crucial to prevent over- or under-application.

Foliar Feeding: Spraying a diluted fertilizer directly on the leaves for rapid nutrient absorption. This approach is used to replenish micronutrients or to treat nutrient deficiencies. It gives a quick nutrient boost to plants but doesn't replace soil-applied fertilizers.

Drip Irrigation: Delivering liquid fertilizers directly to the plant's roots through irrigation. This fertilizer application technique is most recommended and efficient. It uses fertilizer injectors and drip systems to deliver nutrients directly to the base of plants, feed the entire garden, and reduce nutrient loss. Drip irrigation systems are ideal for feeding soluble fertilizers to horticultural and high-value crops.

Some Tips for Using Organic Fertilizers

Improper usage of organic fertilizers can contribute to water pollution, plant nutrient deficiency or toxicity, and salt burn. Here are some tips to get the most out of your lawn and garden fertilizers and prevent damage to your plants.

Avoid Overdoing it: Even though these fertilizers are natural, using too much of them can be harmful to plants, causing poor health and nutrient burn. Start with a little and add more as needed.

Know Your Soil: A soil test can reveal the nutrients your garden soil is lacking. This will help you select the appropriate type of organic fertilizer and prevent nutrient imbalances.

Compost First: To avoid burning plants, manure and other "hot" fertilizers should be composed or aged first.

Timing Matters: Applying fertilizer at the wrong time can limit its effectiveness. Always follow the recommended timing for each fertilizer and plant. Avoid applying fertilizer in late fall and winter. It is best to use them during the growing season when plants are actively growing.

The Bottom Line

Building healthy soil is one of the most important things you can do to strengthen and improve your garden, and using organic fertilizers will help improve your soil over time. Knowing about organic fertilizers can lead to a more sustainable gardening experience, whether you aim to reduce your environmental impact or simply use a natural method for growing your plants.

Your gardening will be healthy and sustainable if you understand and meet the nutrient needs of your soil and plants by using appropriate organic fertilizers. Selecting organic, aka natural fertilizers, will help your garden flourish and move toward a more sustainable environment.

Try these natural fertilizers, and see your garden thrive.