A sustainable approach to water includes not only where your water comes from but how you use it. 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.
This is a repost of one of our most popular posts with over 5,000 reads.
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.
Different irrigation suits different plants and situations. Drip irrigation delivers water very efficiently, albeit slowly directly to the root zone. Sprinklers deliver a lot of water over a large area at relatively low cost. New rotating stream sprinkler technology is a tremendous leap forward in this area. Some research on the best type of irrigation for your plant types is a good investment.
There are expert online tools available if you live in Melbourne, regional Victoria, Adelaide or Alice Springs – you can find links to these below.
The major factor that determines how much water plants need is evaporation, but you can make a significant difference to the evaporation rate and improve water efficiency in your garden. Here are three areas where you can reduce evaporation:
- Mulch acts as a blanket on the soil, reducing evaporation by up to 20%.
- Dry winds will rapidly increase evaporation. Placing plants, especially thirsty plants, out of the wind and in partial shade will reduce evaporation rates.
- Even something as simple as watering in the morning or evening will significantly reduce evaporation and the amount of water required to keep your plants healthy.
Zone your plants
A very practical consideration is something called zoning. If you put plants that need about the same amount of water together you can water that area for a standard amount of time, it is then easy to provide and program irrigation, you will save a great deal of watering time walking back and forth and you are less likely to over or under water particular plants.
Alternative water sources
There are also popular alternative solutions to using mains water such as rainwater from your roof and greywater from your house. These systems can cost almost nothing to thousands of dollars to set up but once established the benefits continue for years at little or no additional effort.
To find out how much water your lawn needs in your local conditions, try putting an empty 25mm deep tuna tin out on the lawn under the sprinkler. When the tin is full, switch off the sprinkler. When the tin has dried out it is time to water again.
Mowing the lawn affects water use too, never cut lawn by more than 1/3 of its height as it will over stress the grass and will require more water to grow again. Some people like to leave the mown clippings on the lawn to act as a mulch – this will work well if you are only trimming the lawn.
Some useful watering tools:
What methods of watering have you found useful? Comment and tell us below.