7 Best Aquarium Plant Fertilizers

Posted by on 6/5/2024

Whether you're looking to correct an aquatic plant nutrient deficiency, or you're starting your aquarium plant-keeping journey, a good plant fertilizer is an absolute must for any hobbyist with an interest in planted tanks.

The more intense lighting you provide, the more nutrient uptake your plants will require, and decaying fish waste is often not enough when used as a nutrient source. In this post, we'll recommend some of the best plant fertilizers in the hobby, so that you can build the planted tank of your dreams.

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Hobbyists new to plant keeping should be looking for key ingredients, Potassium Nitrate, Monopotassium phosphate, and Micronutrients (CSM). These are the organic compounds that fuel plant growth, which is throttled by light intensity. In the wild, these nutrients are readily available in an aquatic plant's native habitat, but in an aquarium, it's up to you to recreate these conditions.

Seachem's Flourish

First on our list of Plant Fertilizers comes from Georgia-based Seachem Laboratories. This aquarium-focused business has been around for over 40 years, specializing in marine and freshwater products. One of their most popular products is their fertilizer, known as Flourish. This liquid-based solution is an all-in-one fertilizer, meaning all you need to do is follow the dosing instructions for your tank size. No extra nutrients are needed.

Aquarium Co-Op Easy Green

Hobbyists who frequent YouTube may already be familiar with Seattle-based Aquarium Co-Op. Owner Cory McElroy offers a variety of Aquarium Co-Op branded products on his website, one being Easy Green. Easy Green is another all-in-one liquid solution, and with over 4000+ 5-star reviews, you know your plants will be in good hands with this product.


Aquarium enthusiasts who run high-tech CO2-injected aquariums may be familiar with NilocG, which sells aquarium-related equipment out of their warehouse in Albany Oregon. Similar to Aquarium Co-Op and Flourish, NilocG offers an all-in-one liquid plant fertilizer known as NA TRHIVE+. Hobbyists can purchase a variety of bottle sizes, ranging from 16.9 ounces to 1 gallon.

API Leaf Zone

Perhaps best known for their water testing kits, API has been independently owned in the hobby for over 60 years until it was recently acquired by Mars Inc. in 2003.  Just like the previously mentioned fertilizers, Leaf Zone is an all-in-one liquid fertilizer and is sold in both 18 oz and 16 oz sizes. 

Root Tabs

Hobbyists new to keeping aquatic plants are frequently recommended Root Tabs. These pill-like capsules are buried in the aquarium substrate, and over time release nutrients directly into the water column. Both API and Seachem offer Root Tabs for sale, but aquarists should be aware that Root Tabs are often the most expensive fertilizer method. Typically you'll see about 30-50 root tabs sold in a single pack, but an aquarium that's 10 gallons in size can require up to 6 tabs every few months! Keep this in mind when deciding on these fertilizers.

Root Tabs
API Root Tabs

Nutrient Rich Substrate

Unlike the supplemental fertilizers on our list, it's worth noting that nutrient-rich substrates also act as plant fertilizers. Substrates such as Eco-Complete (now known as Eco-Planted) and Seachem's Flourite Black provide nutrients for plants, but over time, this nutrient source eventually runs out. Still, for those looking to establish a newly planted tank, it's worth pursuing a nutrient-rich substrate to set your tank up for success.

Dry Fertilizers

Veteran hobbyists tout the benefits of dry fertilizers. These are the raw, powder-like organic compounds that plants require in their raw form. These compounds are KNO3 (Potassium Nitrate), KH2PO4 (Monopotassium Phosphate), and trace elements, CSM+B. Hobbyists can measure the appropriate amount of nutrients depending on their tank size by using an online dry dosing calculator, or they can mix these compounds with water to create a liquid solution (similar to the all-in-one liquid solutions we've previously mentioned in the post.) If you're an experienced planted tank hobbyist or plan on building a massive planted tank, then there's no question that dry fertilizers are the way to go - just be sure to store them in a safe, cool, and dry location (such as a cabinet.) 

Dry Fertilizer
Light Fish
KH2PO4, an aquatic plant dry fertilizer


That wraps up our list of the best aquarium plant fertilizers. As you can see, the options mentioned in our list are beneficial for different types of planted tank enthusiasts. Advanced hobbyists may prefer dry fertilizers, intermediate may be interested in all-in-one liquid solutions, and beginners may opt for root tabs. It's entirely up to you and your budget! 

Do you have experience using some of these plant fertilizers? Let us know in the comments below, and be sure to visit our marketplace, where you can buy and sell anything related to aquatics with other hobbyists.

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Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!