The 10 Best Organic Fertilizers

Updated May 25, 2018 by Gia Vescovi-Chiordi

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We spent 45 hours on research, videography, and editing, to review the top choices for this wiki. If you are looking forward to enjoying all the fruits and vegetables you are growing in your garden, make sure you don't harm them or yourself by adding any toxic or potentially dangerous chemicals to their soil. These organic fertilizers will enable you to produce more healthy, tasty and nutritious foods than you can find at your local supermarket. When users buy our independently chosen editorial picks, we may earn commissions to support our work. Skip to the best organic fertilizer on Amazon.

10. Fox Farm Big Bloom

The micro-brewed Fox Farm Big Bloom uses earthworm castings and bat guano to bring new life to your potted plants, fruit trees, vegetables, and botanicals. It promises to intensify flower fragrance and increase the production of essential oils.
  • works well for all flowering plants
  • highly concentrated solution
  • overfeeding can do serious damage
Brand Fox Farm
Model FX14091
Weight 1.3 pounds
Rating 4.2 / 5.0

9. ChickenFuel Compost

Mixing a bag of the OMRI-listed ChickenFuel Compost in with a few bags of standard topsoil is a great way to create rich planting beds. It ensures plenty of microbial activity that will help you grow large, healthy shrubs, fruits, and vegetables.
  • can make 50 gallons of compost tea
  • loaded with potassium and phosphorus
  • a bit expensive for the quantity
Brand ChickenFuel
Model chickenfuel-3lb-bag
Weight 2.8 pounds
Rating 3.7 / 5.0

8. Organic Plant Magic

A 1/2-pound bag of Organic Plant Magic can be mixed with 32 gallons of water to create enough compost tea to cover 1,000 square feet of soil. It's a kid- and pet-friendly blend of natural ingredients that's suitable for use on all types of plants.
  • contains over 55 minerals
  • no animal byproducts
  • instructions are incomplete
Brand Organic Plant Magic
Model pending
Weight 8 ounces
Rating 4.1 / 5.0

7. Shin Nong Pro

You can dish out a bag of all-purpose Shin Nong Pro quite liberally, as the formula presents no danger of over-concentration. Use it to help your plants develop more robust root structures, ensuring better water retention and enhanced growth.
  • helps improve disease resistance
  • maximizes microorganism activity
  • can promote mold growth
Brand Shin Nong
Model pending
Weight 3 pounds
Rating 4.9 / 5.0

6. Neptune's Harvest

A bottle of Neptune's Harvest contains a blend of seaweed and hydrolyzed fish, bringing the nutrient-rich gifts of the ocean to your houseplants or garden. It promises to produce blooms that are more fragrant, plentiful, and longer lasting.
  • has an indefinite shelf life
  • 1 gallon can cover 8000 square feet
  • fishy smell may attract wildlife
Brand Neptune's Harvest
Model FS136
Weight 2.5 pounds
Rating 4.5 / 5.0

5. EarthPods All Purpose

Sustainably produced in the United States and effortless to use, EarthPods All Purpose boast a hearty combination of essential minerals, fungi, and worm castings densely packed into capsules. Simply push one into the soil near the center stem and water as usual.
  • wonderful for the elderly
  • eco-friendly packaging
  • not well-suited to large projects
Brand Earthworm Technologies
Weight 2.4 ounces
Rating 4.3 / 5.0

4. Espoma Tomato-Tone

The highly specialized blend of plant food in a bag of Espoma Tomato-Tone contains no fewer than 15 essential nutrients that help you to grow larger, tastier, and more nutritious vegetables. It'll help accelerate their growth, too.
  • stymies blossom end rot
  • can mix into or sprinkle on soil
  • produces a strong odor
Brand Espoma
Model 346
Weight 4.1 pounds
Rating 3.8 / 5.0

3. Dr. Earth Home Grown 704P

Dr. Earth Home Grown 704P can give your garden the fuel it needs to produce delicious, nutritious vegetables, even if they're not planted in the most fertile ground. Simply mix it into the dirt at initial planting or soak it in water and apply the liquid to existing beds.
  • formula is rich in probiotics
  • feeds 60 square feet
  • non-gmo project verified
Brand Dr. Earth
Model 704P
Weight 4 pounds
Rating 4.9 / 5.0

2. Unco Industries Wiggle Worm

Believe it or not, the Unco Industries Wiggle Worm Soil Builder is actually odor free, which you'll appreciate given the nature of its provenance. Turn a handful or two into each planter pot or hoe some into your garden beds for quick results.
  • made from pure earthworm castings
  • safe for use around kids and pets
  • great value for the price
Brand Unco Industries
Model WWSB15LB
Weight 14.5 pounds
Rating 4.6 / 5.0

1. Humboldts Secret

Especially effective on faltering crops, Humboldts Secret jump starts growth by activating enzymes and speeding up the photosynthesis process. This proprietary blend is simple to mix and can breathe new life into everything from trees and flowerbeds to your favorite shrub.
  • offers easy storage
  • a little goes a long way
  • can increase yields up to 20 percent
Brand Humboldts Secret
Model 2 Ounce
Weight 2.4 ounces
Rating 4.7 / 5.0

Selecting The Right Organic Fertilizer

Fertilizers are an invaluable aid in raising and maintaining plant life as they serve to replace the nutrients that are depleted from soil as a plant grows. With the right type and ratio of fertilizer, planted fields, beds, and pots need not be left fallow and need little fresh soil year after year, leading to greater efficiency and ease of horticultural management that farmers and gardeners from eras past could scarcely have imagined.

Whether you are concerned about your health and the wellbeing of other people who come onto your property and/or eat foods you raise, if you are dedicated to protecting the environment and eco-system, or if you just don't trust the chemicals used by major agribusinesses, using organic fertilizer is a great way to help your plants robust growth while minimizing exposure to potentially harmful substances.

More often than not, selecting the right organic fertilizer for your needs is as easy as considering what types of plants you will be assisting and then doing a bit of research and reading. Most fertilizer blends are created with specific types of plant in mind, so whether you are hoping to grow robust, productive tomatoes or if you want to restore your lawn to its healthy, verdant luster, with some looking, you can surely find the right fertilizer formula for your needs.

What might require a bit more thought is not so much determining the right fertilizer formula, but the best physical type of fertilizer to use. Organic fertilizers come in pellets, powders, stakes, and liquid form. And not all types of fertilizer medium are equally appropriate for varied applications.

If you are trying to grow a full bed of flowers (such as pansies or moss roses, for example), then turning a handful of powdered fertilizer into each cubic foot of soil is a good approach. For helping citrus trees create tasty, robust fruits, driving stakes of fertilizer into the ground a few feet away from their trunks is the way to go. Pellet fertilizer is slower to break down than powders, thus is great for use around established shrubs, trees, and bushes that will benefit for extended feedings. And finally liquid based fertilizers are great for smaller beds, potted plants, or even for mixing into the water of hydroponic systems.

Perfect Soil Preparations

Any gardener or landscape professional with a bit of knowledge and experience knows that too much of a "good thing" is actually a bad thing; that is to say, too much fertilizer can be every bit as detrimental to a plant than too little. In fact, it can worse: in high enough concentrations, fertilizers can effectively "burn" a plant, potentially even killing it.

Fertilizer burn typically occurs when an oversupply of nitrogen salts draws too much moisture out of a plant, leaving its leaves (and sometimes its stalk and even the roots) dried and damaged. Fertilizer burn can affect everything from the grass of a lawn to edible food crop plants to flowers and beyond.

The best way to avoid damaging a plant by the use of too much fertilizer also happens to be the best way to prepare soil for new plantings, as well: pre mixing soil and fertilizers creates a fecund material ready to help flora grown and thrive. Whether you are preparing a bed for a new year of tomato or pepper plants or you're turning new earth into the ground around a well established citrus tree or row of hedges, choosing the right fertilizer and then mixing it with healthy soil -- and, ideally, some homemade compost as well -- will do wonders for your vegetation.

If you make your own compost, you are well on your way to enjoying wonderfully healthy plants. Mixing a few scoops of compost into each wheelbarrow full of soil (whether fresh soil or that you scoop up from your own land) and then adding a handful of fertilizer can create a nutrient-rich material that may well see your plants needing nothing but water and sunshine for an entire growing season. To make compost, be sure remember the basic guideline of a twenty to one ratio of carbon to nitrogen. That is to say, for every twenty parts of a compost blend made of substances like straw, pine needles, or sawdust to one part nitrogen rich materials like food scraps, grass clippings, and coffee grounds.

Differences Between Organic And Inorganic Fertilizer

As far as plant is concerned, there is little difference between organic and inorganic fertilizers. Both substances deliver compounds the plants need for ideal growth and development, the only difference being the source of these compounds. The real difference between the two substances is that an inorganic fertilizer helps plants without doing much (if anything) to renew thew health of the soil itself. Organic fertilizers can both help a plant grow and can help replenish the nutrients and balance of the surrounding earth beyond the roots.

In an inorganic fertilizer, the nutrients that will feed the plant are usually derived from petroleum products. Petroleum can be refined into a potent source of the nitrogen a plant needs, but it is a non-renewable resource that can damage the earth during extraction and, ironically, damage it again when put back in the ground as a fertilizer. That's because while nitrogen (and other compounds, like phosphorous) can help plants grow, they also kill off many of the minute organisms that live in soil and which are usually responsible for helping maintain the healthy, natural balance of fertile land.

So fields, beds, or gardens treated with inorganic fertilizer may see a year or two (or even more) of healthy plant growth, it's likely that each year will require more and more fertilizer to yield the same results, thereby further damaging the soil. Eventually, earth exposed to too much inorganic fertilizer simply must be left barren for years or more, or else must be replaced.

Thus while a plant may grow just as well whether it receives organic or inorganic fertilizer, the gardener or farmer concerned about the greater good will always choose the naturally derived approach.

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Last updated on May 25, 2018 by Gia Vescovi-Chiordi

Born in Arizona, Gia is a writer who fled the dry heat of the desert for Southern California, where she continues to enjoy drinking beer, overanalyzing the minutiae of everyday life and channeling Rick Steves.

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