Written By
Published Sep. 20, 2021

Hydroponics is the process of growing plants in a water-based solution instead of using soil. The system consists of a reservoir to hold the nutrient-rich solution; grow trays to contain the plants; a growing medium, like peat moss, perlite, or Rockwool to help support the roots; and pumps to move the solution from the reservoir to the grow trays for absorption. An air pump can also be used to bring oxygen to the plants, while grow lights may be necessary to control the amount of light the plants are exposed to in order to stimulate photosynthesis.

The final addition to this system is the hydroponic fertilizer that provides important nutrients to the plants through the water. The best hydroponic fertilizer to help your plants thrive depends both on the type of plants you’re growing and the nutrient content of the solution. The list of top products below will help you find the best hydroponic fertilizer for your home.

How We Picked the Best Hydroponic Fertilizers

Methodology

We brought years of experience setting up and operating home grows in vetting the best hydroponic fertilizer. We researched over 35 different hydroponic fertilizers to determine the best five for this list. Careful consideration was given to the nutrient content of each solution, the application method, the formula components, and the suitability of each hydroponic fertilizer for inexperienced growers as well as veterans. 

Hydroponic systems need nutrient additives for the plants to grow and thrive, so it was important to identify products that had a good balance of the top three nutrients for hydroponics: nitrogen, phosphorus, and potassium. Equal consideration was given to whether a product was a liquid or granular formula, with the pros and cons of each format taken into account to ensure that the best products were selected. Multi-part fertilizers tend to be better for experienced growers who know how to balance the various nutrients, while single-part fertilizers are easier for beginners who want to ensure that their plants have the most essential nutrients for healthy growth.

Best Hydroponic Fertilizers: Reviews & Recommendations

Best Overall: Humboldts Secret Starter Kit Pack

Complete Hydroponic Nutrient Solution

Ensure the health of the plants in your hydroponic system with this complete multi-part nutrient solution. Humboldts Secret

Check Price

Why It Made the Cut: Designed for starting new hydroponic grow setups, this fertilizer includes several different nutrient solutions to help optimize plant growth.

Specs:

  • Primary nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium, concentrated enzymatic formula, iron
  • Quantity: Makes 125 to 150 gallons of fertilizer.
  • Components: Multi-part fertilizer system

Pros:

  • Comprehensive multi-part system
  • Plant enzymes enhance photosynthesis
  • Makes 125 to 150 gallons of nutrient solution
  • Compatible with all grow mediums

Cons:

  • Complex multi-part nutrients may not be suited for beginners

The goal of hydroponics is to grow plants without soil, which is accomplished by using a nutrient-rich, water-based solution that provides the plants with everything they need to grow and thrive. This starter package from Humbolts Secret is an excellent option for an experienced grower looking to start a new hydroponic grow because it comes with five nutrient solutions as well as concentrated plant enzymes, allowing the user to customize the nutrients to the plants’ needs. 

The hydroponic fertilizer kit is a multi-part system that includes all of the most important nutrients for successfully growing plants in a hydroponic setup including nitrogen, phosphorus, potassium, calcium, magnesium, and iron. While the product does include recommended measurements for nutrient addition, the multi-part component system may not be suitable for beginners.

Best Value: General Hydroponics MaxiGro Plant Food

Single-Part Granular Formula

Newcomers to hydroponics will appreciate this simple, effective nutrient solution that breaks down completely in water. General Hydroponics

Check Price

Why It Made the Cut: This affordable, single-part component solution is excellent for increasing the growth and potential of seedlings and cuttings.

Specs:

  • Primary nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, molybdenum
  • Quantity: The 2.2 pound package makes up to 200 gallons of fertilizer.
  • Components: Single-part fertilizer system

Pros:

  • Simple formula is good for beginners
  • Encourages seedling and cutting growth
  • Suitable for both hydroponic and soil-based grows

Cons:

  • Molybdenum in the formula 

If you’re starting out with seedlings, this simple, single-part component system is a great choice. The package for General Hydroponics MaxiGro Plant Food comes with 2.2 pounds of granular hydroponic fertilizer formulated to be completely water-soluble, reducing the chance of nutrient lock-out due to accumulated salt deposits on the roots of the plants. This fertilizer has a simple formula that is intended to be used through the entire life cycle of the plant, though it’s specifically designed to stimulate the growth of seedlings and cuttings, making this product ideal for new hydroponic systems. 

This hydroponic fertilizer can also be used for adding nutrients to soil, so it’s ideal for people who have both hydroponic and soil-based plants. The fertilizer  includes nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, and molybdenum in the nutrient formula. Note that according to the manufacturer any vegetables, fruits, herbs, grains, or other products that are grown with this fertilizer should not be fed to ruminant animals, like cows or goats because of the molybdenum in the mix.

Best Single-Part Fertilizer: Botanicare Pure Blend Pro Grow

Ideal for Beginners

The Botanicare single-part component fertilizer is easy to measure and apply to both hydroponic and soil systems. Botanicare

Check Price

Why It Made the Cut: The easy-to-use, all-in-one formula includes nitrogen, phosphorus, potassium, calcium, and magnesium, ensuring that plants have the primary nutrients necessary to thrive.

Specs:

  • Primary nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium
  • Quantity: 1 quart makes 192 gallons of fertilizer
  • Components: Single-part fertilizer system

Pros:

  • Single-part formula is simple for beginners
  • Suitable for both hydroponic and soil-based grows
  • Terpene-enhancing nutrient system

Cons:

  • Single-part system is difficult to customize to plant needs

For plants in a hydroponic system to grow and thrive, they have to be provided with a balanced, water-based nutrient solution that includes nitrogen, phosphorus, and potassium. This single-part fertilizer includes these important nutrients and also contains calcium to help strengthen the plant cell walls and magnesium to enhance photosynthesis and increase the phosphorus intake.

The Botanicare fertilizer can be used in both hydroponic and soil-based systems, making it a great choice for beginners who may be transitioning between a soil-based garden and a small hydroponics set-up. This formula is also ideal for improving the expression and action of terpenes within the plants. Terpenes are frequently noted and highlighted by cannabis growers, but they exist in all plants and the potency of the terpenes can greatly enhance the smell, taste, and even medicinal benefits of the plants. However, this single-part formula doesn’t allow for the same level of control over specific nutrient amounts as multi-part fertilizers provide. 

Best Multi-Part Fertilizer: General Hydroponics Flora Grow, Bloom, and Micro Combination

Balanced Multi-Part System

Used by NASA and Antarctic research teams, this impressive multi-part system is an excellent choice for the experienced grower. General Hydroponics

Check Price

Why It Made the Cut: Used by NASA and Antarctic research teams, this multi-part fertilizer lets you adjust the nutrient mix to suit your specific plant needs.

Specs:

  • Primary Nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron
  • Quantity: FloraBloom:1 gallon; FloraMicro: 1 gallon; FloraGro: 1 gallon. The amount of fertilizer produced after mixing with water varies with plant needs.
  • Components: Multi-part fertilizer system

Pros:

  • Suitable for both hydroponic and soil-based growing systems
  • Three-part system with bloom, grow, and micro nutrients
  • Nutrients can be customized to plant needs with multi-part system

Cons:

  • Not suitable for beginners
  • Product weight may increase shipping costs

One of the main benefits to a hydroponics setup is that it doesn’t require soil to grow healthy, fruitful plants. While this is great for individuals who prefer to have an indoor setup, it’s even more useful for Antarctic researchers and NASA astronauts who don’t have accessible soil for growing. This multi-part hydroponic fertilizer is used by scientific researchers in Antarctica and astronauts on the International Space Station to grow healthy plants without the need for soil.

The fertilizer is made up of various key nutrients including nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and iron, but growers can customize the mix to suit their needs instead of relying on an all-in-one solution. Each of the three bottles contains about 1 gallon of nutrient solution, for a total product weight of 31.2 pounds. This weight may increase shipping costs, but the liquid solution is still easier to measure and add to a hydroponic system than a granular fertilizer.

Best Dry Fertilizer: MASTERBLEND 4-18-38 Complete Combo Kit

Grow a Salad

Set up a small hydroponic system in the kitchen and enjoy freshly grown tomatoes with the granular Masterblend nutrient solution. MasterBlend

Check Price

Why It Made the Cut: Grow strong, healthy tomatoes, lettuce, and other vegetables with this multi-part granular hydroponic fertilizer.

Specs:

  • Primary nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium, iron
  • Quantity: Tomato and vegetable Formula: 1 pound;  Calcium Nitrate: 1 pound, Epsom salt magnesium sulfate: 0.5 pounds
  • Components: Multi-part fertilizer system

Pros:

  • Ideal for vegetable growth
  • Water soluble formula reduces risk of nutrient lockout
  • Easier to store for long periods than liquid fertilizer

Cons:

  • Must be measured out by weight for accurate mixture

Optimize the growth of tomatoes, lettuce, bell peppers, and other home-grown vegetables with this multi-part, granular nutrient solution by Masterblend. The kit comes with a complete hydroponic fertilizer formulated to stimulate vegetable growth, but it also includes a bag of calcium nitrate and a bag of magnesium sulfate so that experienced growers can adjust the nutrient solution to suit the current stage of plant growth. The water-soluble formula ensures that the granular fertilizer breaks down completely in water, reducing the risk of nutrient lockout.

The multi-part hydroponic fertilizer contains nitrogen, phosphorus, potassium, calcium, magnesium, and iron to help the plants thrive. The granular fertilizer is easier to store for a long period of time than a liquid formula, though it does need to be measured by weight, so users will need to invest in a scale to ensure accurate nutrient treatment. 

Things to Consider Before Buying Hydroponic Fertilizers

To ensure that your plants get the appropriate amount of nutrients through each stage of growth, it’s important to take the time to understand the various factors that can make one hydroponic fertilizer more suitable than another. Some key considerations include the type of plants you want to grow, the nutrients present in the fertilizer, whether the fertilizer is liquid or granular, and whether the nutrient solution is a single-part or multi-part component system.

Type of Plants

Before thinking about a hydroponic fertilizer, one of the most important things to decide is the type of plant you want to grow. Different plants have very different nutrient requirements, so while there are basic fertilizers that can help almost any plant, these more universal products are just the bare basics for a hydroponic setup. This is because hydroponics relies on fertilizers and nutrient solutions to provide the correct amount of key nutrients to specific types of plants. Basic levels of nitrogen, phosphorus, and potassium are all good for the plant, but may not be sufficient for plants to thrive.

Common home hydroponics plants include tomatoes, cucumbers, lettuce, spinach, strawberries, bell peppers, and various herbs. To get the best outcome with your home hydroponics system, take some time to do additional research on the specific plants you are growing and the nutrients they need to develop properly.

Nutrients

The type and quantity of nutrients in the hydroponic fertilizer determine the suitability of the nutrient solution for your  crop. The most common nutrients in hydroponic fertilizers are nitrogen, phosphorus, potassium, calcium, and magnesium.

  • Nitrogen is one of three nutrients that make up the NPK ratio typically displayed on the front or side of the hydroponic fertilizer package. Nitrogen is vital for healthy stalk and leaf growth because it’s an important component in the creation of chlorophyll, so it helps to facilitate and enhance the process of photosynthesis.
  • Phosphorus is the second nutrient included in the NPK ratio. It helps to prevent disease while warding off pests, but the real purpose of phosphorus is to aid in the synthesis of proteins in order for the plant to build healthy roots, buds, and flowers.
  • Potassium is the third and final part of the NPK ratio. Like nitrogen, potassium is primarily responsible for facilitating and improving photosynthesis, though it doesn’t contribute to the creation of chlorophyll. Instead, potassium regulates the carbon dioxide intake of the plants. Without carbon dioxide, photosynthesis cannot occur. 
  • Calcium supplements are used by people to help improve bone density and health. Similarly, calcium is used by plants to build strong, stable cell walls, forming key components of the plant’s structure. It also acts to neutralize cell acids, which in turn allows for better water and nutrient absorption.
  • Magnesium acts both as a booster to improve phosphorus intake and a building block to create chlorophyll and enhance photosynthesis.

Single-Part or Multi-Part Components

Hydroponic fertilizers typically come in either a complete, single-part component system or a multi-part component system.

  • Single-part component fertilizers are ideal for beginners because they don’t require a lot of experience to measure out and add the required amount of fertilizer. The combination of nutrients in single-part solutions is designed to be suitable for a variety of plants throughout their growth cycle. 

Multi-part component fertilizers are better for experienced growers who can identify the specific needs of their plants. The multi-part system allows growers to select and measure the best nutrients to use at any given time depending on the needs of the plants. While the additional complexity of this system isn’t a good choice for beginners, it does provide experienced growers with a way to address specific growth issues, resulting in a healthy, fruitful yield.

Liquid or Granular

Another decision to make when selecting the best hydroponic fertilizer for your home setup is whether you prefer to work with a liquid or granular nutrient solution.

  • Liquid hydroponic fertilizer is usually easier to measure and add to the hydroponic system, though these products need to be properly mixed before use. Also, keep in mind that if the cap of the fertilizer bottle is left off for an extended period of time the nutrient quality can be affected. 

Granular hydroponic fertilizer tends to be more difficult to measure because it needs to be weighed before being added to the hydroponic system. However, granular fertilizer can be stored for a longer period than liquid fertilizer.

FAQs

Q: What is hydroponics?

Hydroponics is a method of growing plants that doesn’t require soil. Instead, the plants grow in a water-based, nutrient-rich solution with a growing medium that helps to support the roots. This method of growing is ideal for areas where the soil content is poor or where there is little room for planting seeds.

Q: Can I use regular fertilizer for hydroponics?

The only real reason to use regular fertilizer instead of hydroponic fertilizer is that regular fertilizer is a cheaper alternative. While it’s possible to do this, using regular fertilizer can increase the risk of nutrient lockout due to an excess amount of salts. Additionally, the nutrient content of regular fertilizer isn’t designed for hydroponics, so it may not have the necessary nutrients to support the plants, resulting in a mineral deficiency in your plants and a reduced yield.

Q: How do you add fertilizer to hydroponics?

Use either a single-part or multi-part fertilizer by adding the nutrients to the water in the hydroponic system. Follow the directions provided by the fertilizer manufacturer in order to measure the appropriate amount before mixing it with water. If the fertilizer content is too high, it can cause nutrient lockout. Also, keep in mind that if you’re not replacing the water in the hydroponics setup, then you’ll need to test the pH and mineral content before adding fertilizer to help maintain a balanced solution within the hydroponics system.

Q: What do you need to set up a basic hydroponic system?

A basic hydroponic system requires the following items:

Hydroponic fertilizer or nutrient solution, which is a mix of macronutrients and micronutrients in a water-based solution.
-Grow lights or accessible sunlight to give the plants a primary light source for photosynthesis.
-Growing medium to help support the roots of the plants and transfer nutrients from the solution to the plant.
-Grow trays or grow pots to hold the plants.
-An air pump to help pump oxygen into the system, which is absorbed through the roots of the plants.
-A water reservoir to hold the water-based nutrient solution.
-Submersible pumps to move the water-based solution from the reservoir to the grow trays or pots where it can be absorbed into the growing medium and up through the roots.

Final Thoughts

The impressive Humboldts Secret Starter Kit Pack is the ideal multi-part choice for a new hydroponics grower, but if you prefer a single-part formula, then the affordable General Hydroponics MaxiGro Plant Food is a great option.

MORE TO READ