Persea americana in expanded clay granules

Persea americana in expanded clay granules

Hydroponics is a technique where plants do not grow in soil but in water.

This technique has several advantages:

  • the plant is less susceptible to diseases, pests and fungi that can live in soil
  • the plant always has the right amount of water as it absorbs only what it needs
  • the roots receive much more oxygen
  • the risk of rotting is smaller
  • there is a water reserve, you can check visually whether there is enough in the reserve and do not have to feel the soil with your finger to guess if your plant needs watering
  • since the plant takes the exact amount it needs, less water is wasted, so there is less spillage of water
  • the plants grow faster and fuller than in soil because they receive the necessary amount of water and nutrient
  • you can sow immediately in hydroponics
  • some mature plants can be transferred from soil to hydroponics

It is perfect for those who do not have green fingers. But even for more experienced enthusiast, hydroponics is interesting and fun to experiment with.

There are also a few drawbacks:

  • complete systems with outer pot, inner pot, water level meter and substrate are quite expensive. But such beautiful but expensive systems are not required, it is very easy to make a basic setup with cheaper alternatives without being a champion at DIY.
  • the material is not always easy to find, you need to seek specialized growshops because the average plant shops, DIY shops and garden centers rarely have the materials and fertilizers. Fortunately, there are some growshops on the internet where you can order on-line and have your products delivered home.

How does hydroponics work?

The basic principle is simple:

  • the plant grows in a special substrate for hydroponics of porous rock, rock wool or another inert and non-rotting material.
  • the water is in a reserve at the bottom of outer pot or in a separate tank. The plant is not in the water but above it (or next if you have a separate tank). Thanks to a water meter you can check visually how much water remains in the tank.
  • the hydroponic fertilizers are specifically designed to be dissolved in the water.

Besides this basic principle, there are many variations in substrate and in the way the water arrives at the roots, also depending on the use as houseplants, office plantings or horticulture.

In this basic scheme, the plant is grown in expanded clay pellets, also known as Ex-clay or by their trademarks: Hydroton, LECA, Hydrokorrels. These are baked, porous clay granules that expand like popcorn when heated. The small holes in the clay particles, suck the water up by capillarity.

Hydroponics with clay pellets

Hydroponics with clay pellets

Is hydroponics especially suited for water-loving plants?

No, hydroponics is suitable for all types of plants and actually less suitable for large water-loving plants, such as papyrus, because they need so much water every day that it’s actually easier if they are grown in soil.

For smaller wetland plants and carnivorous plants, however, hydroponics is very suitable.

Furthermore, almost all indoor plants, but also garden and patio plants and even vegetables, can be grown in hydroponics.

Even succulents and cacti are grown successfully in hydroponics since the plants are not in the water but above it. They take exactly what they need, nothing more and nothing less.

For orchids, this is an excellent technique and even bonsai do well in hydroponics.

Clay pellets

Clay pellets

Image sources

  • Persea americana in expanded clay granules: Own work
  • Hydroponics with clay pellets: Own work
  • Expanded clay granules: Lucis


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