Hydroponic plant food is unique to hydroponic systems. Hydroponic plants need micro- and macro-nutrients just like “normal” plants do, and hydroponic fertilizers are designed specifically to deliver those nutrients to hydroponic plants for healthy plant growth. There are liquid fertilizers or powdered fertilizers. You can also opt for organic hydroponic fertilizers.

Choosing a fertilizer types of hydroponic fertilizers

Plants need 16 different elements in order to power all of their cells’ functions and fuel things like reproduction and growth. Each element is received differently. For example, some are taken in through stomata while others are taken up through the roots. 

Complicating things even further, some nutrients need to be in a specific form in order to be available to the plant. For example, nitrogen must be part of a nitrate molecule.

Hydroponic systems require carefully curated fertilizers to create a nutrient solution. Different plant types need different fertilizers. To illustrate, vegetables need more nutrients than leafy greens.

Fertilizers can be in either powder form or liquid form and put into your water solution.

Powdered Fertilizers

The majority of commercial farmers use powder nutrients. The mixing process is complicated. However, they’re easy to ship and store and can be bought in bulk. 

Powdered formulas come in different NPK ratios, and you choose which one depending on the plants you’re growing. 

Liquid Fertilizers

Liquid fertilizers for hydroponics are easier to use because they’re already mixed and all you have to do is add them to water. However, they’re more expensive because they’re heavier to ship. 

Liquid fertilizers come in solutions that are either 1, 2, or 3 parts. Depending on the plants or growth phase, the amount you add from each bottle is different. You also don’t have to supplement anything because it’s all included.

There are lots of available brands and it’s important to research and read reviews. But at the end of the day it often comes down to user preference.

One benefit of liquid fertilizers is that there’s only a small chance of residue building up in your piping or water trays. 

Organic Fertilizers for Hydroponics

While nutrients are able to be organic, it’s hard to get the full range of nutrients from just one source. Therefore gardeners commonly blend many organic fertilizers together to create their organic fertilizer.

Most products usually have a concentrated fish emulsion combined with liquid nutrients like liquid calcium. You may have to add organic nitrogen to this.

One hard part about organic nutrients is that it can be hard to achieve high levels of calcium and nitrogen, and it’s even harder to measure the levels when you’re a beginner. 

The systems need microbes from the root zone to turn organic compounds into nitrogen. However, this often takes too long.

While there are plenty of commercial organic fertilizers for hydroponic plants on the market, the best way for small growers or farmers to get organic fertilizer is to utilize vermiculture, aka worm farmer. 

One thing of note is that plants don’t do better depending on if you use organic or inorganic hydroponic fertilizers. The argument more so is about which produces healthier food.

How do hydroponic plants get nutrients?

Inert substrates allow hydroponic plants to get their nutrients.

Substrates have no mineral components. They let the roots overgrow while holding the plant in place. Some inert substrates include:

  • Cotton wool
  • Vermiculite
  • Perlite
  • Coconut fiber
  • Mineral wool

It’s vital that the substrate doesn’t encourage soil pathogens.

So the substrates let the plants sit on top of the water and suck up the nutrients from the fertilizer through their roots.

How many fertilizers do I need?

Plant food for hydroponics may come as 1-part-, multi-, or many-part mixes.

One-part mixes are very easy to mix- simply follow the instructions on the label. However, they’re not ideal to make stock solutions because some nutrients become solid in high concentrations.

Multi-part mixes are the perfect middle ground and are chosen by most growers. They’re simple to mix and let growers make stock solutions because the difficult compounds stay separate.

Many-part mixes usually only make sense when you’re running a huge operation.

Adding nutrients to your system

To add nutrients to your hydroponic system, you need an accurate scale and a container. You also need buckets, gloves, and stirring rods.

Most people choose mixing tanks or sumps because of their turbulence. Other options include a 5-gallon bucket. Your nutrients need turbulence and plenty of space in order to mix all the way. 

Choose a spot in your hydroponic system that has both of these qualities.

You can mix either nutrient separately and then combine them, or add them to your tank separately.

Read the label on the mix you’re using and follow its instructions. 

Check your nutrient levels every day. You’ll probably end up needing to add some more nutrients every couple of days because the plants are using them, as well as because of dilution.

pH dictates the “usability” of nutrients

pH is how acidic or alkaline a water-based solution is. It’s on a scale of 0-14, with lower numbers being more acidic than higher numbers.

pH is important to hydroponic nutrient solutions because it determines your plants’ ability to absorb nutrients. 

If your solution is overly acidic, the micronutrients will be absorbed in toxic levels and macronutrients will be lacking. On the other hand, a solution that’s too alkaline won’t let micronutrients be absorbed. 

Having the correct pH ensures optimal nutrient uptake.

What’s Electroconductivity for?

Electroconductivity, or EC, measures the concentration of mineral salts that are dissolved in the water. That means that the EC needs to increase when the plant needs more nutrients.

An EC that’s too high indicates too many nutrient salts in the roots. When this happens, you need to improve drainage and regulate the nutrient solution. One way you can do this is by using osmosis water to dilute the solution instead of tap water.

Your solution’s EC should be somewhere between 1.2 to 2.0. The hydroponic fertilizer as well as the plants’ needs determine what the EC should be. 

You should always start with an EC of 1.2 and increase it from there.

Best Hydroponic Nutrients

The three main macronutrients include nitrogen, phosphorous, and potassium (NPK) and are absorbed the most. Let’s break down what each one does.

Nitrogen is responsible for leaf growth and color. It provides proteins, chlorophyll synthesis, amino acids, and nucleic acid.

Phosphorous is in charge of the plants’ RNA and DNA synthesis. It’s also in charge of seed, root, flower, and stem development.

Potassium helps synthesize carbohydrates and proteins. To a lesser extent, it helps flowers, roots, and stems develop.

Micronutrients are also needed for plant growth, although they’re needed in smaller quantities. Micronutrients include boron, copper, calcium, iron, sulfur, magnesium, and zinc.


Here are some commonly asked questions along with their answers.

Can I use regular fertilizer for hydroponics?

You can technically use regular fertilizer for hydroponics, but your results will be much better if you use hydroponic fertilizer. The ratios of nutrient will be incorrect. In addition, regular fertilizers can drastically change your pH. Meanwhile, fertilizers for hydroponics have pH buffers. If you want to make sure you get all the required essential nutrients, use hydroponic plant food.

How do hydroponic plants get nutrients?

Hydroponic plants get nutrients from hydroponic fertilizers while being suspended in inert substrates.


There’s a lot to know about hydroponic plant food! Hopefully by now you understand the basics. Things like EC and pH probably don’t pop into your mind when you think of fertilizer, but they’re just as important as the hydroponic plant food itself. 

Luckily, you can grow prolific plants armed with this new knowledge!