Which Planted Tank Fertilizer is Right for You?


Which plant-based fertilizer is best for you?

Have you ever wondered how hobbyists, professionals, and even experts can create beautiful aquascapes full of plant life? The three key ingredients that make aquatic plants happy are:

– Use good lighting. – Add nutrients as necessary.

Because the world of fertilizers is a confusing and complicated maze, many beginners will overlook this last piece. Although dry fertilizers seem to be the most popular choice because they are cost-effective and can be customized, many people don’t mention the steep learning curve or how chemical balances can easily get out of line if they don’t understand what they are doing.

So Do Aquatic Plants Really Need Fertilizers?

The simple answer to your question is “Yes” if you want your plants thrive, not just survive. The building blocks that plants need to grow are just as important as the nutrients they require to survive.

– Macronutrients refer to nutrients that plants consume large amounts of, such as nitrogen and phosphorous. – Micronutrients can be nutrients that plants only require in small quantities, such as iron and boron.

Plants can grow differently if one or more of these compounds are missing. Check out this plant deficiency diagram that shows what happens when certain elements or minerals are missing:

(Source: Aquatic Plant Central)

Hobbyists use fertilizers to ensure their plants have all the nutrients they need. Let’s take a look below at the most common and readily available fertilizers for your average tank.

The Easy Option: Aquarium Co-Op Easy Green

You might be thinking “Uh, I just purchased my first few plants.” I have no idea if they’re doing well, much less what nutrients they might be missing. Where’s the easy button?” That’s where Aquarium Co-Op’s Easy Green all-in-one fertilizer comes in. We originally developed it for our own in-store use because we wanted something that was:

1. It is easy to use and does not require you to measure out tons of supplements. It is higher in nutrients and more potent than the ones on the market. Because a little goes far, it is reasonably priced

Easy Green all-in-one liquid fertilizer

Intended For: aquariums that are at least moderately stocked with plants

Easy Green is rich in all three macronutrients necessary for healthy growth. This fertilizer is not suitable for tanks with high bioloads, or only one plant. If you have an aquarium with normal bioloads and a bunch of plants that you want to look nice, this is the fertilizer for you. And yup, it’s fish and invertebrate safe.

Note: “High bioload” generally refers to aquariums with lots of animals, poop, and excess food floating around. High levels of organics can cause nitrogen and phosphorus to build up in the water, which is good for plants. However, if not managed properly, high bioloads can also produce a lot of ammonia, which is toxic to animals.

Ingredients: all three micronutrients (nitrogen-phosphorus-potassium) and the top six macronutrients – in higher concentrations, for maximum effectiveness

Cost: $15 for 8 oz bottle

Easy Green is an all-in one fertilizer which covers most of your needs for plants. Easy Green is now available in Canada via Amazon.com. Easy Iron can be used to boost iron levels in those with lots of red plants. If you need help fighting algae, consider adding Easy Carbon. That’s all there is to it.

If you have plants that prefer to feed from their roots rather than the water column (such as Cryptocoryne, sword plants, and bulb plants), then get a pack of Easy Root Tabs to stick into your gravel, sand, or other inert substrate.

Easy Fertilizer Package

Directions One pump per 10 gallons (or twice a week) for low to medium lighting tanks.

A 55 gallon low-light tank will require one bottle to last for about a year. If your aquarium has medium to high light, then dose two to three times a week. Use test strips to measure the water in your aquarium and aim for 50ppm of Nitrates. It’s easy as pie.

Bottom Line: It’s called “Easy Green” because it’s easy to use and great at making green leaves. If you’re a beginner looking for a comprehensive, bulletproof fertilizer or you’re not getting the results you want, Easy Green may be just the thing you need.

API Leaf Zone is the Cheap Option

API Leaf Zone is likely to be among the liquid fertilizers available at your local pet shop. The cheapest bottle should be enough.

API Leaf Zone

Intended For: low-tech planted tanks with really high bioloads

Translation: your plants are fairly low maintenance and are currently living off fish waste and flakes in the tank.

Ingredients only contains potassium and iron

Because API assumes that you have a high-bioload tank with a ton of nitrogen and phosphorus, the only macronutrient you’re missing is potassium, which Leaf Zone provides. Because it aids with leaf growth, it also adds iron. But… what about all the micronutrients?

Cost: $6.50 for 8 oz bottle

Can’t beat the price, but you get what you pay for.

Directions: 5 mL per 10 gallons per week

This is a very diluted product, so you will go through the bottle quickly.

The bottom line: While it won’t give you super-growth, it’s better than nothing.

The Mix-and-Match Option: Seachem Flourish Series

Seachem Flourish fertilizer line

Designed for: any plant tank

Seachem offers many supplements because every plant tank is different. This is due to bioloads, water hardness, low light vs. high lighting, etc. Seachem wants you be able to customize your nutrients to meet your needs. This means that their fertilizers may not be suitable for beginners.

Ingredients it all depends. The majority of novices should start off with Flourish Comprehensive. It contains most elements and minerals that low-light plants need. Seachem recommends that you add Flourish Trace to your diet on separate days in order to get enough micronutrients. Seachem has made it possible to separate key nutrients into products, so you can purchase the building blocks that you need individually if you are still experiencing plant deficiencies.

Price: $10-$70 or More

Flourish Comprehensive or Flourish Trace cost about $10.50 for a 16.9-oz bottle. API Leaf Zone and Flourish Comprehensive are very low in the two main macronutrients, nitrogen and phosphorus. This is just in case your tank has a high bioload. If you don’t, then you can spend another $10.50 on Flourish Nitrogen and another $10.50 on Flourish Phosphorus… by the time you’re done adding all the necessary nutrients, you may be buying a lineup of seven bottles or more.

Directions: totally depends

Not only are multiple bottles cumbersome to manage, but each one has very different amounts and treatment times. Some bottles say “5ml per 60gallons per week”, while others say “2.5ml/40gallons twice a weekly but add more as needed.” In order to prevent novices from overdosing on fertilizer, the recommended nutrient levels are quite low.

Bottom Line: Flourish Comprehensive contains a lot of the bare minimum nutrients needed for growing plants, but be prepared to buy additional supplements and to spend time fine-tuning your dosing schedule and amounts.

For more details on the Seachem Flourish series, check out our video on How to Use Aquarium Fertilizers.

Final Tips for Aquatic Plant Fertilizers

No matter what nutrient sources you use (e.g., fish poop, root tabs, liquid or dry fertilizers, potting soil, CO2 injection), most likely they will help. Because every person’s preferences and setups are different, there is no one “best product” in the market. The key is to do your research, make a decision that works best for you, and learn from your mistakes. Your aquarium is a living ecosystem that is constantly changing – water, number of fish, plant size – so have fun seeing nature in action and earning your aquatic green thumb!