Indoor Gardening: What Is A Passive Hydroponic System?

Passive Hydroponic System for indoor plants

What Is A Passive Hydroponic System?

A passive Hydroponic System is the most simplified and less troublesome way of growing your indoor plants. It uses some type of technique to hang a plant and supply water in the reservoir where the roots are suspended. The water provided is added with nutrient solutions that contain all the needed minerals, including macronutrients and micronutrients, to help plants reach through their potential growth. It also helps determine how much nutrient solution the plants receive and how long it takes to refill the water reservoir.

Passive Hydroponic System for indoor plants
Passive Hydroponic System for indoor plants

In the world of hydroponics, there are two types of passive hydroponics which are soilless and soil. The soil type is the common soil used in gardening, while the soilless type that is also classified as a “soil” in hydroponics is the use of growing media such as Leca as a soilless potting mix.

Why Leca is perfect for indoor gardening?

LECA or Hydroton Clay Pebbles
LECA or Hydroton Clay Pebbles

LECA, also known as Hydroton or Clay pebbles is a growing medium used for a soilless potting mix to grow your plants. It is an acronym that stands for Lightweight Expanded Clay Aggregate, consisting of baked clay balls that absorb and expand when soaked in water. Leca acts as a sponge-liked medium that absorbs water to keep your plants hydrated. However, although Leca is used as a substitute for soil, it does not contain nutrients that your plants need, and you will have to add the nutrients to the water where you are going toSem soak Leca.

Since Leca is a different growing medium, normal plant fertilizer is not advisable to provide the nutrients your plants need; rather, a special hydroponics fertilizer needs to be purchased.

Now the question is, why should you switch to Leca? Even though it does not contain nutrients that your plants need, there are many benefits when you use Leca. The benefits are as follow:

  • It is easier to keep your plants hydrated by soaking Leca to water with nutrients solution.
  • The risk of getting pests is reduced since Leca does not contain live organisms that pests might feed on.
  • The risk of root rot is lesser in Leca, for it only absorbs water, and overwatering is prevented.
  • It is easier to check in on your plants every day or twice a month when using Leca.
  • Leca is a reusable growing medium that you can reuse after thoroughly cleaning it.

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Semi Hydroponic Methods for House Plants

There are six basic methods under hydroponics, and each method has a different layout. These methods are as follow:


Self Watering Transparent Flower Pot
Self Watering Transparent Flower Pot

It is the most simple and cheap system, wherein a wick or several is used to absorb the nutrient solution from the reservoir and deliver it to a sterile medium. This system is recommended for small set-ups and beginners since it does not require pumps or drainage systems. There are also available self-watering pots that use this technology.

Ebb and Flow

This system uses a timed pump that regularly floods the container with a nutrient solution, and then the drained solution goes back to the water reservoir. The flooding system works well for the greenhouse garden, which can maintain the roots damp.


The most complicated system is the Drip System. It uses hoses and drip lines to individually deliver the nutrient solution to the plants and is suited for larger plants.

Nutrient Film Technique

NFT is designed for a large greenhouse setup. In this system, plants are hanged in a plastic basket and laid in trays. The nutrient solution is delivered through tubes to hydrate the plant’s roots, and then the drained solution goes back to the reservoir.

Water Culture

This system is best suited for fast-growing plants like lettuce, wherein a tray made out of Styrofoam or other floating material is placed on the reservoir.


Aeroponics is the most expensive system, where the plant’s roots are hanged in a less growing medium, and then the water is misted to the hanging roots to keep the plant hydrated and deliver the nutrients needed.


  • Hydroponics, Albopepper Clayton, (2017),
  • What Is A Passive Hydroponic System, Garden Culture Magazine (2012),
  • Passive Hydroponics & Container Hydroponic Systems, Garden & Greenhouse
    Tilley, Hydroponic Gardening Indoors, Gardening Know-How
  • What is Leca and why is it useful for plants, Plant Care For Beginners
  • The pros and cons of using Leca to grow your plants, Plant Care For Beginners
  • Indoor Gardening Techniques, Love to Know
    Willis, (2018),
  • The Indoor Grow Methods and Techniques, Indoor Farm Life

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