The Best Organic Fertilizers, Vetted

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Feed your plants and build great garden soil with these high-quality organic fertilizers.

All plants need nourishment. Lawn grass and houseplants typically need a little help to grow their best. That’s where fertilizer comes in.

Organic fertilizers stimulate and support the natural processes plants use to feed themselves. The fertilizer feeds soil-dwelling microorganisms that then deliver the nutrients to plants. Over time, they increase soil organic matter, which leads to improved soil aeration and water-holding capacity and a better physical growing environment.

The best organic fertilizer makes edible or ornamental plants healthier, providing a balance of nutrients, quality ingredients, and an application method that suits the gardener. In this guide, we list some of the best organic fertilizers on the market and offer shopping tips on finding the right one for domestic plants.

1. BEST OVERALL: Jobe’s Organics All-Purpose Granular Fertilizer
2. BEST BANG FOR THE BUCK: Espoma Plant-tone Organic Fertilizer
3. BEST LIQUID: Sunday WonderFert All-Purpose Garden Fertilizer
4. BEST ALL-PURPOSE: Neptune’s Harvest Organic Fish & Seaweed Fertiliser
5. BEST SLOW-RELEASE: Jobe’s Organics All-Purpose Fertilizer Spikes
6. BEST STARTER: Espoma Bio-tone Starter Plus Plant Food
7. BEST FOR FLOWERS: Dr. Earth Organic Bud & Bloom Booster
8. BEST SOIL BUILDER: Unco Industries Pure Worm Castings Organic Fertilizer

Before You Buy Organic Fertilizer

Because each garden is unique, shoppers may want to assess important factors like drainage, types of plants, weather, soil composition, and preferred application before buying an organic fertilizer. It is recommended that gardeners test the soil to determine its pH level before choosing a fertilizer since this can affect if and how plants absorb the nutrients in the fertilizer.

Whether they’re sold in liquid or dry form, the best organic fertilizers have an optimal nitrogen-phosphorus-potassium (NPK) ratio, or the percentage by volume of nitrogen, phosphorus, and potassium in the mixture. A high-quality mixture usually consists of natural ingredients like plant scraps, animal waste, and minerals. They’re typically easy to apply, require minimal processing, and maintain a consistent texture throughout.

Before buying and applying an organic fertilizer to houseplants, a garden, or the lawn, shoppers may want to check the label to make sure the mixture doesn’t contain toxic or synthetic ingredients. Organic fertilizers are carbon-based and improve soil health over time by adding organic matter to the soil. They also support biodiversity, increase soil water retention, and do not contain harmful chemicals. However, because they must break down in the soil to benefit the plant, organic fertilizers can take longer to be effective, although they do last longer overall.

How We Chose the Best Organic Fertilizers

To build our list of the best organic fertilizers available, we researched a variety of ingredients, effectiveness, application methods, and ease of use. Some are made with animal byproducts, which are known to provide excellent fertilization benefits, and others are made with minerals or microbial ingredients. Purists might prefer the animal-based products, but the smell may be too much for some, which is why our top recommendation is a granular fertilizer, which is easy to apply to many kinds of outdoor and flowering plants.

We also considered the type of application: dry, liquid, or foliar. Buyers should be comfortable applying their preferred fertilizer, so we’ve included options to suit most preferences. Certain fertilizers are easy to apply once each season, while others require bimonthly application for best results, which may appeal to green-thumb gardeners.

Finally, we looked for products that contain the Organic Materials Review Institute (OMRI) label. OMRI is a 501(c)(3) nonprofit organization that provides an independent review of products that are intended for use in certified organic production and processing. The organization reviews products like natural fertilizers against organic standards, adding those that meet these standards to its OMRI Products List. It then lets manufacturers include an OMRI List label on the approved product.

Our Top Picks

Several well-known brands produce excellent organic fertilizers. The following recommendations take into consideration each product’s NPK analysis, ingredients, application method, and effectiveness in each category.

Best Overall

Jobe’s Organics All-Purpose Granular Fertilizer

From Jobe’s Organics, this all-purpose granular fertilizer is a fast-acting and balanced (4-4-4 NPK) product made from feather meal, bone meal, processed poultry manure, and sulfate of potash. It also includes multiple strains of beneficial archaea, bacteria, and fungi that quickly facilitate the transfer of nutrients to plants. Over time, the microbes in this organic fertilizer work with the plant to improve the surrounding soil structure.

This is an optimal regular maintenance fertilizer for annuals, perennials, edibles, trees, shrubs, and almost all outdoor gardens. An excessive odor may be detected with this product. That odor can be minimized by mixing this fertilizer with soil rather than applying it on the surface.

Product Specs

• Type: Animal-based and mineral-based
• Ingredient(s): Feather meal, bone meal, nitrogen, phosphorus, potassium (potash), processed poultry manure
• Quantity: Available in 1.5-, 4-, 6-, 8-, and 16-pound bags

Pros

• Fast-acting granular-style fertilizer enhanced with proprietary microorganisms; effective on vegetables, flowers, trees, and shrubs
  Apply every 4 to 6 weeks, which is less often than liquid fertilizer
  Received OMRI Listing; contains no substances that, at their given concentration, are considered health hazardous

Cons

• May cause fungus growth indoors; may cause slight eye irritation

Get the Jobe’s Organics granular organic fertilizer at Amazon. 

Best Bang for the Buck

Espoma Plant-tone Organic Fertilizer

Espoma Plant-tone is a slow-release 5-3-3 organic fertilizer derived from feather meal, poultry manure, cocoa meal, bone meal, cottonseed meal, greensand, humates, sulfate of potash, and sulfate of potash magnesia. Added beneficial microbes activate in the garden soil to increase the fertilizer’s efficiency and improve soil structure.

This fertilizer is an excellent general-purpose choice for season-long use on flowers, vegetables, trees, and shrubs. It is not meant for houseplants, though, unless they will spend several weeks outdoors. Espoma’s Plant-tone is a high-quality product but can emit a bit of a smell, but that odor can be minimized by mixing it into the soil. Any unused portion can be stored in a sealed container so that the scent doesn’t attract animals.

Product Specs

• Type: Animal-based, plant-based, and mineral-based
• Ingredients(s): Feather meal, poultry manure, bone meal, alfalfa meal, greensand, sulfate of potash, sulfate of potash magnesia
• Quantity: Available in 4-, 8-, 18-, 36-, and 50-pound bag sizes

Pros

• This all-purpose organic fertilizer is great for all flowers, vegetables, trees, and shrubs
• Ready to use and requires no mixing; long-lasting, slow-release feeding using microbes
• Only needs to be used once a month during growing season
• 100 percent all-natural and organic ingredients with no fillers or sludges
• USDA-certified biobased product; approved for organic use by the California Department of Food & Agriculture (CDFA)

Cons

• This organic fertilizer has a strong odor that some users may find unappealing
• Product bag is not resealable, which can make storage a bit tricky

Get the Espoma Plant-tone organic fertilizer at Amazon, Ace Hardware, or The Home Depot.

Best Liquid

Sunday WonderFert All-Purpose Garden Fertilizer

Sunday is an innovative company that’s still pretty new to the garden fertilizer market, but it prides itself on reducing environmental impact with toxic-free products. It also has a modern website and offers a subscription service, although Wonderfert fertilizer can be purchased individually as well.

Wonderfert is Sunday’s all-purpose garden fertilizer, ideal for all flowers, vegetables, trees, and shrubs. As a mineral-based fertilizer with a 10-2-6 NPK, ingredients include nitrogen, potassium, and phosphorus sourced from urea, urea-triazone, potassium acetate, and potassium phosphate. The slow-release nitrogen helps with sustained growth of plants while the other ingredients support flowering and fruiting. It can be used for both outdoor and indoor plants.

The fertilizer comes in a resealable stand-up pouch with an attachable sprayer, making it very easy and convenient to use. It can also be applied by attaching to a hose and spraying or mixing it into a watering pail. One pouch covers about 800 square feet, and the product can be applied every 4 to 6 weeks during the growing season.

Product Specs

• Type: Mineral-based
• Ingredient(s): Nitrogen, potassium, and phosphorus sourced from urea, urea-triazone, potassium acetate, and potassium phosphate
• Quantity: 42.3-ounce pouch

Pros

• Versatile since it can be used for all flowers, vegetables, trees, and shrubs
• Convenient to use in a resealable stand-up pouch with an attachable sprayer included
• OMRI-Listed product rapidly and uniformly absorbed by indoor and outdoor plants

Cons

• This product’s manufacturer is new to the garden fertilizer business

Get the Sunday organic fertilizer at Target, Lowe’s, or Sunday.

Best All-Purpose

Neptune's Harvest Organic Hydrolized Fish & Seaweed

Neptune’s Harvest has created a 2-3-1 NPK organic fertilizer made from North Atlantic fish and seaweed. Similar to kelp meal fertilizer, this convenient liquid concentrate can nourish most types of plants, indoors and out. Simply mixing the concentrate with water according to the label directions and applying it to the root zone gets the job done.

The high phosphorus ratio stimulates deep root growth while boosting flower and fruit quality. This is a concentrated fish-based fertilizer, so the undiluted concentrate has an odor; however, the smell fades quickly, even when used on indoor plants.

With this organic fertilizer, a little goes a long way. Houseplants require 1 tablespoon per gallon of water, while outdoor plants use ⅛ cup per gallon of water. This product should be handled with gloves while diluting the concentrate.

Product Specs

• Type: Animal-based and plant-based
• Ingredient(s): Fish and seaweed
• Quantity: Available in 18- or 36-ounce bottles, a 1-gallon jug, and a 5-gallon bucket

Pros

• Easy to mix and apply by hand, sprayer, or drip line
• Received OMRI Listing; works well on vegetables, fruit, houseplants, trees, and most foliage
• Has an indefinite shelf life; this organic fertilizer delivers great results
• Those with seafood allergies can safely consume edible plants fertilized with this product

Cons

• Has a strong fishlike odor; must be mixed at each use, not stored when diluted

Get the Neptune’s Harvest organic fertilizer at Amazon or Neptune’s Harvest.

Best Slow Release

Jobe’s Organics All-Purpose Fertilizer Spikes

Jobe’s Organics fertilizer spikes deliver 4-4-4 NPK plant food directly to the plant’s root zone. They eliminate the mess of handling fertilizer with no required measuring or mixing. The 50 included spikes can be used in indoor or outdoor containers or planting beds.

During the spring or early summer months, inserting the required number of spikes (based on container size or square feet of bed space) around each plant does the trick. The formula’s beneficial microbes help break down the fertilizer for plants, increase soil organic content, and boost plant-disease resistance throughout the growing season.

For best results, each spike needs to be fully inserted and covered with soil. Otherwise, several species of mycorrhizal fungi may appear as fuzzy white growth.

Product Specs

• Type: Animal-based and mineral-based
• Ingredient(s): Bone meal, feather meal, potassium (potash), and Jobe’s Biozome (a combination of healthy bacteria, mycorrhizal fungi, and archaea)
• Quantity: Available in 50-spike pack

Pros

• Received OMRI Listing; each fertilizer spike is small enough to place near most plants
• These fertilizer spikes are premeasured to provide plants with nourishment at their roots
• Slow release ensures season-long fertilization; no mess and easy to use
• Odorless, which makes it great for both indoor and outdoor use; prevents waste and runoff

Cons

• A whole spike may be too strong for a smaller houseplant
• May be appealing to dogs; may attract bugs and mold growth

Get the Jobe’s Organics organic fertilizer spikes at Amazon or The Home Depot.

Best Starter

Espoma Bio-tone Starter Plus Plant Food

Bio-tone from Espoma is a 4-3-3 NPK organic fertilizer derived from feather meal, poultry manure, bone meal, alfalfa meal, greensand, humates, sulfate of potash, and sulfate of potash magnesia, plus 13 species of beneficial microbes.

This blend is unique in its incorporation of humates, which are complex organic molecules formed within the earth during the decomposition of ancient plants and animals. These ingredients neutralize the soil and improve the nutrient uptake of plants. The beneficial microbe mix in Bio-tone includes 10 species of fungi that work in conjunction with plants to increase root mass by up to 30 percent, and healthy roots give plants the best start.

The nutrient mix includes 2.4 percent slow-release nitrogen for an extended feed time. Use this fertilizer at planting time for all outdoor plants, including in the vegetable garden, and when repotting houseplants. Be sure to mix thoroughly with the soil to eliminate the smell. Some superficial fungal growth might appear on the soil surface after planting, which is normal.

Product Specs

• Type: Animal-based, plant-based, and mineral-based
• Ingredient(s): Feather meal, poultry manure, bone meal, alfalfa meal, greensand, sulfate of potash, sulfate of potash magnesia
• Quantity: Available in 4-, 8-, 18-, and 25-pound bags and 5-ounce packets

Pros

• Can be used for all flowers, vegetables, trees, and shrubs
• Uses microbes to enhance growth; does not contain sludges or fillers
• USDA-certified bio-based product that’s approved for organic use by the CDFA

Cons

• This organic fertilizer has a strong odor that some may find unpleasant
• Product bag is not resealable, which may make storage a little tricky

Get the Espoma Bio-tone organic fertilizer at Amazon or Ace Hardware.

Best for Flowers

Dr. Earth Organic Bud & Bloom Booster

Dr. Earth Organic Bud & Bloom Booster is a 3-9-4 NPK fertilizer made from fish bone meal, alfalfa meal, feather meal, soft rock phosphate, and mined potassium phosphate. The high phosphorus content provides ideal conditions for flowering and fruiting plants, including bulbs and rhizomes. No chicken manure or wastewater sludge means no bad smell.

This fertilizer has excellent microbe content, with more than 20 strains of beneficial bacteria and fungi to boost plant immunity and increase nutrient efficiency. Mixing this fertilizer into the soil before planting leads to quick root establishment and heavy yields of flowers and fruit. Dr. Earth fertilizer is primarily manufactured for dry application to be incorporated into the soil ahead of planting or as a maintenance fertilizer for established plants.

The label includes directions for making a fertilizer tea as well, which might be beneficial for fruit growers.

Product Specs

• Type: Animal-based, plant-based, and mineral-based
• Ingredient(s): Fishbone meal, bone meal, alfalfa meal, potassium sulfate, feather meal, kelp meal, kelp flour
• Quantity: Available in 1-, 4-, 12-, and 50-pound bag sizes

Pros

• Received OMRI Listing; effective for fruits, vegetables, trees, and flowering plants both inside and outside
• Doesn’t contain genetically modified organisms (GMOs), chicken manure, or sewage sludge; quick-releasing formula; single application lasts several months
• Very affordable compared to many organic fertilizers on the market

Cons

• Some users say this organic fertilizer has a very strong odor
• This organic fertilizer may cause mold growth if not applied properly

Get the Dr. Earth organic fertilizer at