Do plants have to have holes at the bottom of their pots?

Question

If yes, why?

Assuming it is possible to water from the top

Answer 1

The holes are for drainage, obviously, so it's usually a good idea to have pots with holes. However, I have successfully grown several plants indoors in pots without holes; in those cases, I made sure to have a layer of pebbles/small rocks as the bottom layer.

So: Necessary? Not necessarily. Recommended? Definitely. :)

Answer 2

The holes prevent waterlogging, which can make plants rot.

Some plants like Cyclamen prefer to be watered from the bottom ( to keep the tubers dry ), that`s easier with the hole too. Place the pot in a bath of water for about 15 min. and the soil can soak up water through the hole.