Plants in your garden obviously need water to survive, but how often should you do so? An article on National Poly Industries, an Australian company that manufactures water tanks answers this question and others.
It is important to encourage deeper roots to your plants. This can be accomplished by providing your plants with good top soil that is protected from washing away. Your soil shouldn’t be salty or full or solid, and a clay-rich soil at the optimum root depth of your plant is ideal which holds water much better. You want to encourage your plants to grow their root systems deeper than the first few centimetres of topsoil.
Secondly, watering every day or many times a week, encourages roots to remain near the surface. Given constant watering will supply water at the surface, your plant won’t need to dig its root system deeper into the soil, where it is cooler and can access more water during hotter and drier periods.
To encourage deeper and more healthy root systems, it is therefore important to water regularly, but water longer. Try not to water beyond the root depth. It is also important though that your soil can retain water, that it doesn’t just seep into the top soil and flow out the side of your garden. Setting up appropriate barriers around your garden, installing underground irrigation and/or adding mulch can all help.
Read more here: Using Rainwater Efficiently to Water Your Garden