Which is better, using a moisture meter or going by the weight of the pot?

[SakuraDrops]

Originally Posted by estación seca

He means the spaces between pieces of the medium. Imagine a plant container filled with golf balls. There are large air spaces between the golf balls. Now imagine a plant container filled with fine sand. The spaces between particles are very small. If you pour water through the golf balls, their surfaces remain wet, but there are still large air spaces. If you pour water through the fine sand, enough water may be retained between particles that there is no air remaining.

Air is the most important thing for epiphytic orchid roots. Most orchidists grow epiphytes - plants that grow on tree branches with roots exposed. So when potting them the size of individual pieces of medium matters a lot.

Bark is sold in different sized particles. Cattleyas and Phalaenopsis do well in medium to large bark. The larger the bark the more often you will need to water. People in very wet places choose very large bark. If you want to water less often you can choose smaller bark.

Some orchids never want to dry completely when in growth. For these, smaller particle sizes work better. This includes most Dendrobiums, Oncidiums and their intergeneric hybrids, Paphiopedilums and Phragmipediums.

Potting media used can be any of these alone or in combination: Bark, volcanic cinders or scoria, clay balls for horticulture called LECA, horticultural charcoal, perlite, pumice. Many of these are sold in different sized particles. They all have various advantages and disadvantages.

Sphagnum moss also works well as a potting medium for most orchids, but watering plants in sphagnum is very different from watering in particulate media, so that is a different topic.

Thank you so much for explaining!! (: