Everyday, there’s a greater population of avid gardeners. And for those with balcony and courtyard gardens these few pointers will make for potted plant growth excellence and greater enjoyment.

Like all living things, plants survive on 3 components – water, nutrient / food and air.

We water and fertilise our plants regularly, but often forget about the ‘air’ supplement.
With trees, for instance, the roots you see protruding out of the ground are, by chance, there for the air & a quicker access to water & nutrient – the latter coming from its own leaves dropped. That’s why a tree’s root system does not mirror its above-ground shape. The roots travel downward a short distance, then spread out for stability & in search of water.
In regard to balcony & courtyard gardens, it’s a story about watering your plants without drowning them.
In terms of watering, there are 3 types of soil water...
Gravitational Capillary Hygroscopic
When you water, the gravitational passes through the soil or potting mix and is basically unavailable to plants. This water can cause leaching.
Capillary water is available to plants. The amount depends on the soil, organic matter content, time & amount of last watering, plant type, needs, and its ability to extract water from soil.

Lastly, the third type is hygroscopic. This water is unavailable to plants as, due to the forces in water (greater than gravity), it is held too tightly by the soil particles.

Now, many gardeners use pot saucers to collect the water. However, improper use may be doing damage. And ‘crocking’ is another common damaging practice – that is, putting in broken pots or crocks to act as drainage before filling your pot with potting mix.
The thing is that in pot growth, the plant roots must have readily available air. And when sitting in a saucer of water the level of water inside the pot is drowning your plant. Hence the old thinking that to 'crock the pot' would give ready drainage is incorrect. Due to the forces in water the crocking just raises the water table, and then the roots sit in water and the plant drowns.
Thus the best solution is no 'crocking' and to put the pot on feet or broken pots, so that it sits above the base surface, away from potential disease.

Or if you desire, place the pot on feet within a saucer so that the escaping gravitational water will pass the root area.
All this information is available in the Student Handbook for Plant Nutrition by Rod McMillan from Adland Horticultural.

For further info on soil and other matters horticultural, visit Adland

Or study horticulture in Melbourne, Australia at Burnley College.
Also in amalgam, see growing plants in a small space
and how to make your Bird of Paradise flower continually.
And read about the NPK story. It'll inspire you toward great gardening excellence.