How to Water Your Lawn

Like all plants, lawn grasses need water to stay healthy and green. In warm dry summer conditions, many lawns will quickly go brown if water is not applied to the lawn. To supplement natural rainfall many people will irrigate their lawn using an irrigation system, sprinklers, soaker hose or just a hose or watering can.

But there are some tips and tricks to adding water to your lawn so that you keep your lawn grass green and healthy.

• Irrigate Deeply
  When irrigating, irrigate deeply. Water deep down in the soil is where it is most useful to grasses. Healthy lawn grasses will have roots going as deep as 15-60 cm down in the soil. Water at that level encourages the grass to send its roots down in search of the water. If water is ONLY in the soil in the top 10 cm that is where the roots will stay. Grasses with deep roots are more tolerant of drought. Shallow rooted grasses will brown off more quickly.
• Measure Your Irrigation
  If you are using a sprinkler system or sprinkler you can do something as simple as placing a bucket on the lawn and then measuring the depth of the water collected in the bucket. If you find 40 mm of water in the bucket you will know you have applied the equivalent of 40 mm of rain; 40 mm of rain or irrigation will soak soil to a depth of approximately 400 mm (40 cm) assuming no runoff.
• Water Infrequently
  Water deeply and water infrequently. You might think ‘OK, if 40 mm of water soaks down to the depths required, I will apply 10 mm four times a week’. Unfortunately, this will not soak down to 40 cm because the first 10 mm will soak down to 10 cm, much of it will evaporate from the surface soil before the next 10 mm is applied. The next 10 mm may only add enough to soak a little further. Each time much of the water applied will evaporate off before the next application. The deeper the water the more slowly it will evaporate.

• Raise Mowing Height
  Don’t mow your lawn too short. Higher mowing height favours deeper root growth. Mowing short causes roots to stop growing and may cause the death of deeper roots. Short mowing may also expose the soil surface to sun and wind, increasing evaporation and stress on grasses. It also induces grasses to grow more quickly so it doesn’t save you time on mowing.
• Irrigate in the Morning
  Water in the lawn soil is good, water on the grass leaves may be bad. Damp grass blades through the night risks development of fungal diseases such as red thread, Fusarium, Pythium and others. Irrigating in the cool of the morning reduces evaporation from the soil and allows the grass blades to dry through the day so they are not damp through the night.

If you irrigate your lawn with these tips in mind you will develop a deeply rooted healthy lawn that is able to resist drought and disease.

David Brittain
Kiwicare