Managing lawns in hot weather

Learn how to protect your lawn in extreme heat with smart moisture management. Discover why watering properly, using wetting agents and managing expectations keeps South Australian lawns healthy through summer.

In short

Managing lawns in hot weather is not about using excessive amounts of water — it is about managing soil moisture properly. Warm-season grasses such as couch, kikuyu and buffalo are built for South Australian summers and rarely die from heat alone. They survive by going into dormancy and temporarily discolouring when moisture is limited. How green you keep your lawn through summer is, therefore, a choice, not a necessity. Success comes from applying the right amount of water at the right time, ensuring it penetrates the soil evenly with wetting agents, and supporting the lawn with good nutrition. Get soil moisture right, and your lawn will ride out heatwaves far better than one that is simply watered often. 

It’s not about using heaps of water — it’s about managing moisture properly

When extreme heat hits South Australia, most people assume the only way to save their lawn is to pour on more and more water. In reality, successful summer lawn care is not about volume alone — it’s about moisture management.

That means applying the right amount of water, at the right time, ensuring it actually penetrates into the soil, using wetting agents to fix dry and water-repellent soils, and managing expectations about colour versus survival.

Warm-season lawns such as couch, kikuyu and buffalo are built for our climate. In extreme heat, they don’t usually die — they go into dormancy and discolour to protect themselves. How green you keep your lawn through summer is, therefore, a choice, not a necessity. The more green you want, the more precise your moisture management must be.

All lawns can be successfully managed through summer using the right combination of water, wetting agent and fertiliser — not simply by flooding them.

With temperatures set to soar over the weekend and into next week, here’s how to protect your lawn properly.

Why soil moisture matters more than temperature

In South Australia, most lawns are couch, kikuyu or buffalo — all warm-season grasses. As the name suggests, they thrive in warm conditions. Even heatwaves won’t kill them.

What will cause problems in hot, dry weather is poor soil moisture.

When soil moisture is low, lawns brown off rapidly, root systems shut down, heat stress escalates, and recovery becomes slow and patchy. Getting water into the root zone is harder than most people realise — and this is where many lawns fail in summer.

The hidden problem: uneven and water-repellent soils

Most soils don’t wet evenly

Some areas absorb water well, while others don’t. The dry patches are always the first to burn during hot weather.

Many soils become water-repellent

This is extremely common in South Australia. Water beads on the surface, runs off or evaporates before soaking in. You think you’ve watered — but the root zone stays dry.

This is one of the most dangerous lawn problems because it is invisible.

The second problem: misunderstood irrigation systems

Many systems are inefficient

Blocked sprinklers, broken heads and poor coverage are common and often go unnoticed.

Modern sprinklers apply water slowly

Hunter MP Rotators and Rainbird RVANs typically apply around 10mm per hour. To apply a proper deep soak of 20mm, these sprinklers require approximately two hours per zone, whereas older-style pop-ups may only need 20 minutes.

Knowing your system prevents chronic underwatering.

The real goal in heatwaves

The aim is simple:

    Maintain moisture in the root zone.

If moisture is present at depth, your lawn will continue functioning normally, even in extreme heat. If not, stress appears quickly — regardless of how often you water the surface.

Never assume — always check

Water your lawn as you normally would, then dig a small inspection hole with a trowel. Check soil moisture down to at least 50mm and repeat this in several areas, particularly dry patches.

You may be surprised to find that only the surface is wet.

The summer game-changer: wetting agent

Regular applications of a quality liquid wetting agent — such as Paul Munns Betta Wet — are one of the most important things you can do for your lawn in summer. Wetting agents work by breaking down water repellency in the soil, allowing water to penetrate evenly and deeply instead of beading on the surface, running off, or evaporating. This ensures that the water you apply actually reaches the root zone where it is needed most. When soil wets evenly, lawns experience less stress during hot weather, respond better to irrigation, and make far more efficient use of every drop of water applied.

Wetting agent is best applied during the cool part of the morning and watered in thoroughly. Two to three applications across summer will dramatically improve lawn resilience, particularly in sandy and compacted soils common across South Australia. Quite simply, wetting agent is the tonic of life for lawns during hot weather — without it, even heavy watering can be ineffective.

Stronger roots = better drought tolerance

Once soil moisture penetrates evenly and deeply, lawns respond by growing deeper and stronger root systems. Instead of relying on shallow surface moisture, the roots begin drawing water from further down the soil profile, which greatly improves the lawn’s ability to cope with heat and dry conditions. Deeper roots mean the lawn stays greener for longer between watering and recovers faster after stress.

Over time, this improved root depth leads to a tougher, more resilient lawn that requires less frequent irrigation, even during summer. This is exactly how professional sports turf survives extreme conditions — not through constant surface watering, but by building deep, well-supported root systems that can access stored soil moisture when temperatures soar.

Heatwave survival checklist

Before and during heatwaves:

• Check your irrigation system is working efficiently
• Ensure even sprinkler coverage across the entire lawn
• Apply liquid wetting agent in the morning
• Water it in with approximately 25mm of water
• Use catch cups to measure how much water your system applies
• Run sprinklers briefly during extreme heat to cool leaf temperature

Short daytime watering does not water roots — it cools turf via evaporation and prevents leaf scorch.

FAQ — Managing lawns in extreme heat

Will my lawn die in a heatwave?
Highly unlikely. Couch, kikuyu and buffalo are designed for heat. They go dormant when stressed — not dead.

How much should I water during hot weather?
Enough to wet soil to at least 50mm depth. This depends on your sprinkler type and soil condition.

Is it bad to water lawns during the day?
Not for cooling. Short bursts reduce leaf temperature and prevent heat scorch.

Why is my lawn browning even though I water frequently?
Almost always due to water-repellent soil or poor penetration.

How often should I apply wetting agent?
Every 6–8 weeks through summer.

Can I keep my lawn green all summer?
Yes — but it requires good moisture penetration and realistic watering schedules.