This is well worth a read from Michael Smit at The Ripple Effect

How to Water Your Garden

“As the days grow longer and warmer the plants in your garden may need additional watering. Some simple advice will help you use your valuable water to make a great garden. Before you even consider watering, push aside the mulch, stick your finger into the soil – if it is moist below the surface you don’t need to water.

How long and how often should I water?

There are two related questions you should consider when watering:

  • how long should I water for?
  • how often should I water?

Watering your garden every day encourages shallow roots close to the surface. Shallow roots are prone to heat stress, dry out quickly and can only access a small amount of water. Deeper roots live in cooler soil and can access more water so they help the plant cope with hot, dry periods better. You can encourage the roots of your plants to reach deeper by watering less often and making sure the water is penetrating deep into the soil by watering longer.

If you water less often logically you need to water a little longer, but you should avoid watering beyond the root depth as that water will be out of reach. For example most turf only has roots about 25mm deep. Once you provide more than 25mm of water the water is pushed out of reach of the roots. You can water the lawn all night and get the same benefit as if you had watered for 20 minutes in the late afternoon.”

For more great tips including irrigation options, plant zoning, evaporation and alternative water sources read the full article How to Water your Garden | the ripple effect.