How to Fertilize Your Hydroponics


Everything springs from the water in hydroponics. Within a system of gardening that uses no soil, plants may or may not be anchored by some other growing medium like a vermiculite-perlite mix or washed sand. Often plants don't even have that support and instead stay in place, for instance, within a hole cut into a raft that floats in the water. That water is referred to as "nutrient solution" since all the nourishment a plant receives comes from that liquid. The solution consists of a special fertilizer made just for hydroponics gardening. A plant is fertilized automatically as it drinks.

Step 1

Add and mix the hydroponics fertilizer with the water according to the directions on the fertilizer package. Choose the fertilizer that is appropriate for the growth stage of your plant, mixing the amount of nutrient solution appropriate for your garden's needs.

Step 2

Pour water into another container and allow that to stand until you need it later.

Step 3

Let the nutrient solution mixture stand for a few hours or overnight.

Step 4

Check the pH of the mixture.

Step 5

Adjust the pH according to the needs of your plant.

Step 6

Use the fresh nutrient solution in your reservoir.

Step 7

Note the capacity of your reservoir.

Step 8

Take a reading of the nutrient solution with the dissolved solids meter, also called an EC or PPM meter.

Step 9

Write down the pH and EC or PPM readings of the nutrient solution along with the date. The EC/PPM tells you about the nutrient level in the water.

Step 10

Take another reading of pH and EC/PPM when the water level has dropped, recording the readings and the date in your notebook.

Step 11

Add water--not nutrient solution--to your reservoir until it is at capacity again, making note of how much water you added.

Step 12

Test the nutrient level again. If it is at a substantially lower concentration than it should be, add nutrients a small bit at a time until the solution is appropriate.

Step 13

Adjust the pH of the water if it has strayed far from where it should be.

Step 14

Continue adding water to the reservoir as solution is used up. Recording your readings, adjusting the water as needed.

Step 15

Drain the reservoir completely and completely refill with nutrient solution when the total amount of the replacement water you have added equals the capacity of your reservoir.

Step 16

Switch from the growth to the flower/crop fertilizer just before flowering commences.

Tips and Warnings

  • Use safety precautions when using pH adjuster--don't inhale it or get it near your eyes. Also, it could burn your skin. Follow the cautionary advice on the pH adjuster's packaging to the letter and, before you use it, know what to do in case an accident does occur.

Things You'll Need

  • Green growth hydroponics fertilizer
  • Crop/flower growth hydroponic fertilizer
  • Water
  • 2 containers for liquids
  • pH testing strips, testing kit or meter
  • pH adjuster
  • Dissolved solids meter
  • Notebook


  • Nutrient Management
  • Efficient Nutrients

Who Can Help

  • Hydroponics for Home Gardeners-Alabama Cooperative Extension
  • Hydroponics as a Hobby-University of Illinois at Urbana-Champaign
Keywords: hydroponic fertilizer, hydroponic gardening, nutrient solution

About this Author

S. Johnson is a freelance writer and editor of both print and film media who specializes in making the complex clear. A freelancer for over 20 years, Johnson has had the opportunity to cover many topics ranging from construction to music to celebrity interviews, learning a lot and talking to many interesting people.