Perlite, clay pebbles or coconut fiber?

In substrates, three amendments are mixed that do not serve the same purpose: perlite (air), clay pebbles (drainage), and coconut fiber (retention and structure).

Perlite

White volcanic particles. They prevent the pot from compacting. Ideal for seedling trays and indoor mixes.

Clay Pebbles

Expanded clay balls. They go at the bottom of the pot or in hydroponic cultivation. They circulate air and do not rot.

Coconut Fiber

Renewable base that retains water without saturating like heavy peat. Fits well in urban gardens and container tomatoes (tomato cultivation).

If you don't want to guess, use mixed packs of clay pebbles + perlite or all three. The support and irrigation matter too: a perfect substrate with the plant lying down will still get sick.