Simply put, there is no valid reason for drain holes in plant containers. None! It is a dumb idea. They should disappear just like the dodo bird.
Maybe there is a slim justification for drain holes in outdoor clay pots watered with a hose, but definitely not for indoor plants.
Why in the world have scuzzy saucers to clean and water drainage that can cause damage to furniture and floors. It makes absolutely no sense.
Draining soluble salts is given as the reason but you can prove it a ruse often propagandized by houseplant growers who dislike sub-irrigation.
They mistakenly believe that widespread use of sub-irrigated planters (SIPs, aka "self-watering" planters) will negatively affect their revenue. Their fear blinds them to the reality that the market will in fact grow as a result of increased consumer acceptance of growing plants indoors.
Currently it is a declining market limited primarily to the gardening sector rather than the mainstream population at large. Indoor plants should be a hugely popular interior design element but they are not. All one needs to do is look at design and lifestyle magazines with photos of residential and office interiors barren of any living plants.
Growers are well aware that sub-irrigated planters (SIPs) prolong the life of houseplants and make them sustainable instead of short-lived. They know because most of them use sub-irrigation in their greenhouses.
There is no need to take anyone’s advice about this when you can easily prove it to yourself. It will cost very little and the SIP is free. All you need is a SIP made from an upcycled/recyled soda/pop bottle. This post explains about making them.
Once you have the soda bottle SIP, grow a Spider Plant (Chlorophytum). I call them "Canary Plants" because you can use them like the canary in the coalmine to prove to yourself that soluble salts are a bogus threat. You will soon discover that this scare tactic is a hoax, an urban legend, and a myth.Spider Plants are among those reputed to be highly susceptible to soluble salts. So goes the story that if you don’t have a drain hole to flush soluble salts you will have constant brown tipping of the leaves.
When you grow a Spider Plant in a SIP you will discover just the opposite is true. You will have little or no tipping of leaves. You will in fact grow a healthier plant.
Seeing is believing! The Spider Plant in the above photo is growing in a 2-liter soda bottle SIP. It is a very healthy and happy "canary" with no sign of brown leaf tips or any other malady supposedly associated with planters without drain holes.
The false need for a drain hole is a major myth that wastes the energy that was used to grow the plants in the greenhouse and than truck them to your local store. There is nothing green or socially responsible about that. It is a dodo practice.