Best Organic Fertilizers 2021

Helping you decide which is the best organic fertilizer is a bit of a challenge for us since we don’t know what you’re fertilizing!

All plants and vegetables thrive on different proportions of nutrients. Since we’re glad that you are in search of something organic, we will highlight our favorite organic fertilizers for you right here in our guide.

If your kitchen scraps don’t stretch far enough to feed your entire garden or houseplants, these products will help fill in the gap when natural fertilizer isn’t available.

Things to Consider

Here are a few things to keep in mind before you choose a fertilizer.

  • Your Soil. The type of fertilizer you choose depends heavily on the type of soil that you have.

One of the biggest mistakes novices make is purchasing a fertilizer based on popularity. They are later disappointed by the lack of results.

In this case, it may be linked to the pH levels of your soil. The fertilizer you present might be working against the plants rather than helping them!

If you don’t know much about your soil, find out where someone can test it for you at a local garden center. They can give you tips on the type of fertilizer that you need.

  • What You’re Fertilizing. The main ingredients in most fertilizers are nitrogen, phosphorous, and potassium. The percentage of each of these ingredients is listed by weight and varies greatly. What one plant thrives on another may not need. So use the manufacturer’s suggestions on the label to help you understand the types of plants for which it should be used.

Grass, houseplants, vegetables, flowering plants, shrubs… they all need different fertilizers in different quantities.

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Be Patient with Organic Fertilizers

Another common mistake that novices make is to write off a product when it doesn’t yield results quickly enough.

You have to remember that organic fertilizers work differently than chemical fertilizers and it will take longer for you to see the results.

You’re relying more on microorganisms and nature to help break down the fertilizer. The process can be healthier and better for the plant in the long run. It can also be frustrating to the impatient gardener who wants to see immediate results.

Patience! Give it some time and you will be rewarded with long-term results.

Types of Fertilizers

Organic fertilizers usually come in the following forms:


Fish and plant meals are especially useful to gardeners who want finer granules to work into the soil. These are often mixed with other organic ingredients in order to make a custom fertilizer.


These need to be worked into the soil around the plant. Many tend to sprinkle the contents over the soil, but this isn’t the way to use them! Work them into the soil around the roots. This will help them break down directly around the roots so that the plant can absorb it more easily. Also, they will not be washed away by rain or watering.


Most liquid products are sold in the concentrated form and need to be diluted with water.

If you want to put your fertilizer in a spray bottle to spray the foliage or if you need to feed regularly as you water, then liquid fertilizers are an excellent choice.

Top 3 Best Organic Fertilizer Reviews

1. Unco Industries Wiggle Worm Soil Builder 

Wiggle Worm 100% Pure Organic Worm Castings Fertilizer, 15-Pounds - Improves Soil Fertility and Aeration for Houseplants, Vegetables, Gardens, and More – OMRI-Listed and Mineral-Dense
  • IMPROVES SOIL STRUCTURE–Wiggle Worm Pure Worm Castings contain tiny, football-shaped particles that promote light and airy soil to help improve plant soil aeration; Our soil supplement also helps improve the root’s water retention capacity
  • INDOOR AND OUTDOOR USE – Wiggle Worm Pure Worm Castings are great for both outdoor and indoor gardens because it’s odorless; Our worm castings are an excellent organic fertilizer for vegetables, flowers, houseplants, and more
  • Organic fertilizer - pure earthworm castings
  • Excellent for houseplants, vegetables, flowers and more

*Price from:  2024-03-29 at 05:17 EST

Can you get any more organic than earthworm castings?

Worm waste – also known as castings – is so beneficial to plant soil since it is pH neutral and won’t burn your plants with an excessive amount of nutrients. The worm’s digestive system does amazing things to the food they eat and we are rewarded with a rich, organic fertilizer that we can use on vegetable gardens, houseplants, outdoor flowering plants and much more.

This is by far the best organic fertilizer on our list and a staple item to have in any gardening supply kit.

Plants respond so well to this and it is especially helpful to potted plants where worms are less likely to live! ✔️ Let's get it NOW! 

2. Fox Farm FX14049 Liquid Nutrient 

Currently on Sale
Fox Farm FX14049 Liquid Nutrient Trio Soil Formula: Big Bloom, Grow Big, Tiger Bloom (Pack of 3 - 32 oz. bottles)
  • A 3-pack of favorite liquid fertilizers from FoxFarm
  • Get the right juice for the right use
  • Start with Grow Big Hydro for abundant green growth
  • Switch to Tiger Bloom at the first sign of bud set or flowering
  • Use Big Bloom throughout all growing cycles to heal root systems and increase nutrient cycling

*Price from:  2024-03-29 at 09:05 EST

This trio of products from Fox Farm is another great investment for the organic garden.

The Tiger Bloom liquid fertilizer is an extra strength formula with 2-8-4 ratio of nitrogen, phosphorous and potassium (respectively) that will help all of your flowering plants to produce large, healthy buds and blooms.

Grow Big is perfect for vegetable gardens with a 6-4-4 ratio of nitrogen, phosphorous and potassium (respectively) and finally, we see those rich earthworm castings back again along with some super bat guano that works as a general fertilizer for all other plants.

If you’re in need of a variety of organic fertilizers, Fox Farm has the perfect kit for you right here. ✔️ I'm sold, let's get it! 

3. Neptune's Harvest Fish & Seaweed Fertilizer 

Currently on Sale
Neptune's Harvest Organic Hydrolized Fish & Seaweed Fertilizer 36 0z
  • Grow a beautiful vegetable garden
  • Flowers and foliage will be stronger and more colorful
  • Blooms will be more plentiful, fragrant and longer lasting
  • Easy to mix and apply by hand, sprayer, or drip line

*Price from:  2024-03-29 at 14:30 EST

What can fish and seaweed fertilizer do for your garden? A whole lot!

This is a 2-3-1 fertilizer that will work to strengthen foliage, make blooms more colorful, increase the quantity of blooms and make them more fragrant.

You can use this on houseplants, lawns, to help germinate seeds, on outdoor plants (anything from the vegetable garden to the rose bushes).

If you have just a few plants to fertilize, this 18-ounce size will do, but those of you who want to cover the whole garden should opt for the 1-gallon or the 5-gallon size to help you fertilize it all! ✔️ Yes! I want it!