How To Apply Hydroponic Liquid Fertilizer

The hydroponic method of growing plants is more than just a way to get amazing results. It also offers you a whole range of new options when it comes to how you feed your plants. 

With hydroponic liquid fertilizer, you can do something that’s impossible in soil or with any other type of plant food: precisely control the amount of nutrients that go into each plant. 

You don’t have to worry about overfeeding them, either; unlike with traditional fertilizers, there’s no danger of burning your plants if they get too much nitrogen or phosphorus or potassium (or whatever other mineral/elemental compound). 

This article will show you how easy it is to use liquid fertilizer on your hydroponic garden so that your beautiful flowers grow big and strong!

How I Mix My Hydroponic Fertilizer & What Fertilizer I Use
Tips on adjusting pH levels in hydroponics
Importance of nitrogen in hydroponic systems
How to adjust PPM and nutrient levels in hydroponics
DIY liquid fertilizer recipes for hydroponics
FAQs on hydroponic gardening and liquid fertilizer

Mix It With Your Water

The first step to applying a liquid fertilizer is to mix it with your water. For example, if the label on the bottle recommends using one ounce of fertilizer per gallon of water, then you would mix one ounce in one gallon of water. It’s not as complicated as it sounds!

You can use your own judgment when deciding how much liquid fertilizer to add to your reservoir or tank depending on what materials you’re using and how much soil space you need to fill. If there are specific instructions included on the product label, follow those guidelines instead.

If you have a plant that does best with more frequent fertilizing (like tomatoes) then consider adding extra fertilizer at regular intervals throughout the season or just before planting new seeds/seedlings into your system so they’ll be well-fed from day one!

When growing plants in a hydroponic system, it’s essential to maintain the pH level of the nutrient solution. If the pH level is too high, it can cause nutrient lockout, resulting in stunted growth. Learn about how to bring down the pH level in your hydroponic system from our guide to ensure optimal growth of your plants.

Drip On Nutrients As Needed

When growing hydroponically, it’s important to get the right balance of nutrients for your plants. Too little or too much will result in sickly plants or even death. 

You can use a timer to drip on nutrients as needed or use a drip system that allows you to set up a schedule for when the nutrient solution should be delivered.

Direct Application Through The Leaves

You can apply the fertilizer directly to the leaves of your plants by either spraying or misting them. You should avoid getting the fertilizer on the plant’s stems, as it can cause them to rot and become weak.

The leaves are where most of your plants’ energy goes, so they’re important to feed! The best way to do this is by spraying or misting them with a dilute solution of hydroponic liquid fertilizer. 

When you’re using a simple spray bottle, just fill it up with water first and then add some nutrients that way you’ll be sure not to overfertilize your plants.

If you have an air pump in place for aerating your system’s reservoir (which we recommend), then using one of those will help distribute nutrients throughout all parts of your garden efficiently without wasting any product!

If the pH level of your hydroponic nutrient solution is too low, your plants may not be able to absorb nutrients effectively. To remedy this, follow our guide on bringing up pH in hydroponics and maintain an optimal pH level for better plant growth.

Sprinkle It On Top Of Your Substrate

The first thing you’ll want to do is sprinkle the fertilizer on top of your substrate. Make sure that you use a spoon or other implement, as this will make it easier to evenly distribute the liquid fertilizer.

Once you’ve spread it around, you can then give it another little sprinkling for good measure. You want to avoid over-fertilizing your plants at all costs; so don’t go overboard and use too much!

Water With A Hydroponic Bucket System

With this system, you fill a bucket with water and then use a pump to spray the water over the roots. You can either buy a pump or make one yourself.

The first step is to put your plants in their pots. Fill up each pot with soil and make sure there’s enough room that your plant will have room to grow. 

Then place the pot in its spot inside of your hydroponic bucket system, making sure it’s stable without being too close together or too far apart from each other so that all of them get equal amounts of oxygen, light and nutrients!

Now comes time for our next step: filling up those buckets! In order for everything else we need on this list here today, we need some seeds/plants growing inside our hydroponic bucket system; however before doing anything else let’s just make sure we have enough space left over after filling up all 10 pots (you might have some left over).

Nitrogen plays a crucial role in the growth and development of plants. However, the balance between nitrogen and other nutrients is critical in hydroponics. If you notice plants turning yellow or brown, it might be a sign of nitrogen deficiency. Learn about how to add nitrogen to your hydroponic system from our gardener advice guide for healthy and robust plant growth.

Use A Hydroponic Sprayer

If you’re using a liquid fertilizer, you can spray it directly onto your plants. This is the best way to ensure that all of the nutrients are absorbed by your plant roots.

Spray the fertilizer into the air and allow it to fall over your plants from above. If you have small plants that don’t need much coverage, use a hand sprayer. For larger plants or for spraying large areas of soil, use a pump or hose end sprayer instead!

Use A Hydroponic Fertilizer Injector

An injector is a small machine that makes it very easy to apply hydroponic liquid fertilizer. There are many different models, but they all have the same basic components. 

The most important part of an injector is its nozzle, which allows you to accurately deliver your fertilizer into the root zone of your plants.

The next most important part of an injector is its gauge and tubing setup. This will tell you how much water is being used by the system and where it’s going: into your nutrients, or somewhere else! 

If there are any problems with either one of these pieces, then your plants won’t be getting enough nutrients or too much water–making them both healthy and happy!

Adjusting the PPM (parts per million) level of your hydroponic nutrient solution is necessary for ensuring the optimal concentration of nutrients for your plants. Learn about how to adjust the PPM level in your hydroponic system from our expert advice guide to achieve a well-balanced, nutrient-dense solution for your plants.

Create A Homemade Hydroponic Spoon

Here’s a super easy way to apply your liquid fertilizer.

  • Start with a small glass bottle, or something similar that you can cover and use as an applicator.
  • Add water and nutrients to your bottle. You’ll want to mix it so that the nutrients are evenly distributed in the water, but don’t add too much because you don’t want to over-water your plants or waste any precious nutrient solution!
  • Dip the end of your small glass bottle into your substrate or root zone material and then sprinkle some on each plant with long stems until they are covered lightly with fertilizer (but not so much that they will drip down onto leaves). If you don’t have a glass bottle handy, use plastic instead!

Spray It Into The Air And Allow It To Fall Over Your Plants

  • Spray it into the air and allow it to fall over your plants.
  • If you have a very large area, an oscillating fan or two may be necessary to ensure even coverage.
  • You can also use a spray bottle or watering can if you don’t have an air compressor, but this will take much longer to do and will probably require more liquid fertilizer than is needed for spraying with an air compressor because of evaporation and runoff

Maintaining the correct nutrient balance in your hydroponic system is crucial for healthy plant growth. It is essential to adjust the nutrient solution regularly to meet your plants’ changing needs. Learn about how to adjust nutrients in your hydroponic system and maintain optimal growth conditions from our expert advice guide.

Inject It Into Your Humidity Dome

Spraying the liquid fertilizer onto your plant is an option, but it’s not ideal. You can use a spray bottle to apply the liquid directly to the leaves and roots of your plants. 

However, this will cause more damage than good because you’ll be dousing your plants with water as well as fertilizer and this combination could lead to root rot and/or leaf burn.

Instead, I recommend injecting it into your humidity dome or hydroponic system (see below). This way, only fertilizer gets absorbed by the plant; there is no chance of overwatering or over-fertilizing.

Injecting Liquid Fertilizer Into Your Humidity Dome

Can provide targeted and precise applicationMay require additional equipment for injection or spraying
Allows for quick absorption of nutrientsCan be time-consuming if you have numerous plants
Can enhance the absorption of nutrients through leavesOveruse can lead to nutrient burn or toxicity
Ideal for younger or seedling plantsMay result in foliage damage if applied improperly
Can reduce the risk of fungal growthCan increase the humidity levels of the environment

Fertilize Your Plant Through A Spaglum Mat

A Spaglum mat is a polyethylene mesh material that has been specifically designed to hold liquid fertilizers and nutrients, allowing you to water your plants with it.

To apply liquid fertilizer through a spaglum mat:

  • Place the mat over a tray or pot containing the plant(s). Fill up each hole of the mesh with enough liquid fertilizer to cover all of your plants’ roots, but not too much so that it spills out onto the floor.
  • Remove excess fertilizer by taking off any drops on top of foliage or elsewhere in your grow room (you don’t want mold growing anywhere).

Fertilize Your Plant Through A Spaglum Mat

Allows slow and steady release of nutrientsNot suitable for all plant types
Can reduce water usageRequires regular replacement
Reduces fertilizer runoff and wasteCan be more expensive than other fertilizers
Easy to use and applyRequires additional equipment (e.g., irrigation system)
Promotes healthy root growthMay require additional maintenance


If you’re growing your plants hydroponically, your options for fertilizer are more than just a little limited. You can’t just use any old thing from the store and expect it to work. There are some specific things that need to be in the mix if you want great results. So, let’s get started!

Further Reading

If you want to learn more about hydroponic gardening and liquid fertilizer, check out these resources:

How Do You Make Liquid Fertilizer for Hydroponics?: This article provides a step-by-step guide on how to make liquid fertilizer for hydroponics at home using all-natural ingredients.

How to Make Liquid Fertilizer for a Hydroponic System: This detailed guide explains how to make homemade liquid fertilizer and provides tips for maintaining optimal nutrient levels in your hydroponic system.

How to Use Common Fertilizers for Hydroponics: This article provides useful information about using common fertilizers like fish emulsion and seaweed extract in hydroponic systems.


What is hydroponic gardening?

Hydroponic gardening is a method of growing plants without soil by using a nutrient-rich water solution. This method allows for faster growth, higher yields, and better nutrient absorption by the plant.

Why is liquid fertilizer important in hydroponic gardening?

Liquid fertilizer is important in hydroponic gardening because it provides essential nutrients to the plants. Since hydroponic gardening doesn’t use soil, the plants cannot get nutrients from the ground, so they rely on the nutrient-rich water solution to thrive.

Can you make your own liquid fertilizer for hydroponic gardening?

Yes, it is possible to make your own liquid fertilizer for hydroponic gardening using natural ingredients like fish emulsion or worm castings. There are many recipes and guides available online that can help you get started.

How often should I add liquid fertilizer to my hydroponic system?

The frequency of adding liquid fertilizer to your hydroponic system depends on the type of plants you’re growing and the stage of growth they’re in. Generally, it is recommended to add liquid fertilizer once a week or every other week.

What are the best types of liquid fertilizer for hydroponic gardening?

The best types of liquid fertilizer for hydroponic gardening are those that are specifically designed for use in hydroponic systems. Fish emulsion, seaweed extract, and compost tea are all excellent choices. It’s important to choose a balanced fertilizer that contains all the essential nutrients for plant growth.