Growing in LECA | Semi-hydroponics, water reservoir, and plant transition

What is LECA

LECA stands for lightweight expanded clay aggregate: lightweight, porous pebbles made by firing clay. Pores remain inside each pebble and can retain water, while the spaces between the pebbles allow air to reach the root zone. This is why it is used both as a decorative material and as a growing medium.

The pebble size should be chosen according to the size of the roots and the pot; pebbles that are too large can make the plant unstable, while those that are too fine can reduce air pockets. LECA options currently available:

• LECA 2-5 mm, irregular shape - for small pots, fine roots or as part of a mix;
• LECA 8-16 mm, round shape - for larger plants and pots with reservoirs;
• LECA 8-16 mm, 40 L bag - for multiple repottings or large plants.

Hydroponics or semi-hydroponics?

At home, “hydroponic growing in LECA” often means semi-hydroponics: some of the water remains in a reservoir at the bottom of the pot, while the pebbles gradually transport it toward the roots. Not all the roots remain permanently in water. The oxygen between the pebbles is just as important as the water.

LECA does not contain enough nutrients for long-term growing. If the plant remains only in the pebbles, fertilizing adapted to this growing system becomes necessary. If you use LECA only as an addition to a substrate, the need for fertilizing depends on the rest of the mix.

Which plants it works for

It is frequently used for indoor plants with vigorous roots, plants that adapt well to controlled watering and some orchids grown in suitable pots. It is not an automatic choice for every plant. Succulents, cacti, plants with very fine roots or already weakened specimens may require a different drying schedule and a more cautious transition.

Think of LECA as a growing system, not merely as a replacement for soil. Light, temperature, the pot, water level and fertilizing all work together.

Transitioning from soil to LECA

Do not move a stressed, dehydrated plant or one with damaged roots just because LECA seems cleaner. Choose a time when the plant is actively growing. Gently remove as much soil as possible, cut only clearly deteriorated roots with a clean tool and rinse the pebbles before use to remove dust.

It is normal for some roots formed in soil not to adapt immediately. The plant needs to develop new roots adapted to the moisture and air between the pebbles. During the first few weeks, monitor new growth and the condition of the roots; do not suddenly change the water level from one day to the next.

Water, reservoir and fertilizing

Fill the reservoir only after the plant has adapted to the system. At first, moderate moisture and a low water level are more helpful than a permanently full reservoir. Let the reservoir empty occasionally so the roots also receive air; the timing depends on the plant, pot, season and temperature.

Fertilize at a moderate concentration suited to the plant and the product selected. Periodically rinse the pebbles with water to limit salt buildup. If the leaves deteriorate, the roots become soft or the pot smells musty, reduce the water and check whether the roots have enough air.

Frequently asked questions and practical tips

Can I put LECA on top of soil just for decoration?

Yes, but a decorative layer does not turn the pot into a hydroponic growing system. Make sure it does not prevent the substrate underneath from drying or being checked.

Is it best to keep the reservoir full all the time?

Not as a rule. After adapting, some plants tolerate a constant reservoir, while others benefit from short periods when it empties.

Can LECA be reused?

Yes, after thorough washing and, when necessary, disinfection. Do not reuse the pebbles without taking precautions if the previous plant had pests or damaged roots.

Why do white deposits appear?

They are usually salts from the water or fertilizer. Rinse the pebbles and adjust the fertilizer concentration.