How long and often must a lawn be watered to promote deep root growth throughout the warmer months? I live in South East Queensland and the summer temperatures range between 25-35 degrees Celsius. The lawn is Blue Couch (Digitaria didactyla) and it is on a flat surface that receives 6-8 hours sun per day. The subsoil is clay.
Welp, you answered some of my questions!! Clay is great soil. Seriously. Less watering, less adding chemicals, less leaching...watering deeply means to water until your soil is wet at least 4" deep. Take a spade to check. 1" of water per week. Are you on an automatic waterer? Lawns truly need to be trained to grow deep roots...this makes them drought tolerant and saves so much in water bills!! The best way to do this is to soak your lawn until it is wet 4" or more deep. Allow to dry out. If your lawn needs training your grass will tell you when to water again. Simply, walk on your lawn. If your foot prints STAY DEPRESSED and you can still see your footprints, then it is time to water again and deeply!! When your lawn is 'drought proof' with 6" deep root systems that you've trained you should only water once per week. When you water, get straight sided cans such as catfood cans and place them all over your lawn. You'll be able to tell if you've watered 1" as well as where you've been lax. Automatic systems need this check!! If one does not allow the soil to dry and stress the grass ever so slightly, the lawn's roots will be shallow and accustomed to lots of shallow water...a waste as well as the day that it doesn't get watered, the lawn will start going dormant (NOT A GOOD THING). Make SURE you aerate once per year!! Fertilize with good, organic extended release fertilizer (Dr. Earth is super). Always use a mechanical spreader, not by HAND!! KEEP LAWN HEIGHT AT 3". No shorter!! Check out more on other posted questions. I keep getting in trouble for going ON!! Grins!!