Bottom watering is NOT the best way to water your plants
Its ok, bottom watering still does get your plants watered and in the right pots and at the right frequency it will ensure your plants take up the required amount of water but here is thing...
Why bottom watering is not the best way:
If you only bottom water your plants and never water from the top:
You are never flushing the soil,
which prevents a build up of salts in the potting mix from fertilisers & minerals. This can lead to the plant being unable to absorb nutrients & even problems absorbing the water.
Should I bottom water if my plant is hydrophobic?
If you forget to water and your plants become hydrophobic - bottom watering may not even take up enough water to rehydrate the mix effectively. (In this case, completely submerging the pot under water until bubbles stop rising to the surface, is the best answer)
The best way to water is the way nature intended
Like the rain, watering your plants from the top is best.
It ensures all the roots get saturated properly, ensuring they can access the moisture they need.
And it allows the soil to be flushed and any excess salts moved through the drainage holes.
How to top water:
Ideally, you saturate the top of the potting mix with water until you see water exiting the drainage holes of your pot.
Be careful if you use a base tray to catch the excess as they can easily overflow.
It's important to empty the base tray or cover pot of any excess water within a few hours of watering to ensure the plant can drain effectively.
How often should I be watering?
This is dependent on a few things, namely the type of plant & the environment its kept in.
For most indoor plants, you want to allow the plant to dry mostly before providing more water.
Some plants like to be evenly moist so will require water more often.
The rate your plant uses the water depends on your environment