Leca

LECA (Light Expanded Clay Aggregate) is made by heating natural clay in a rotary kiln to around 1,200°C (2,190°F). Gases inside the clay expand during that process, creating tiny air pockets that absorb water.

LECA contains no organic matter, so it's completely sterile, pH-neutral, and free of nutrients or pests. That makes it an inert medium rather than a fertilizer or soil amendment.

Growers use LECA as a soil substitute for semi-hydroponic houseplants, where roots sit among the clay balls while a shallow water reservoir at the base provides passive hydration through capillary action. It's also mixed into traditional potting soil to prevent compaction, placed at the bottom of a container to improve drainage, used to anchor cuttings while roots develop in water, or spread as a top-dressing layer over soil to block pests like fungus gnats from laying eggs.

Key features

• Made by heating natural clay in a rotary kiln to about 1,200°C (2,190°F)
• Porous structure holds up to 30% of its own weight in moisture
• Inert: no organic matter, sterile, pH-neutral, free of nutrients or pests
• Works as a soil substitute for semi-hydroponic growing
• Improves drainage and prevents soil compaction when mixed into potting soil
• Anchors cuttings during water propagation
• Blocks pests like fungus gnats when used as a top dressing

FAQ

What is LECA made of? Natural clay, heated in a rotary kiln to about 1,200°C (2,190°F) until internal gases expand and create a porous structure.

How much water does LECA hold? Up to 30% of its own weight in moisture, held in its porous structure.

Is LECA sterile? Yes. It contains no organic matter, so it's sterile, pH-neutral, and free of nutrients or pests.

Can LECA replace soil? Yes, in semi-hydroponic growing. Roots sit among the clay balls while a shallow water reservoir at the base hydrates them through capillary action.

Does LECA help with drainage? Yes. Mixed into potting soil or placed at the bottom of a container, it prevents compaction and improves drainage.

Can LECA be used for propagation? Yes. It anchors and supports cuttings while roots develop in water.

Does LECA prevent pests? Used as a top-dressing layer over soil, it blocks pests like fungus gnats from laying eggs.