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What is a wetting agent?
A lawn wetting agent, also known as a soil surfactant, is designed to improve water penetration and distribution in the soil. It helps overcome soil water repellency or hydrophobicity, which can cause water to bead up and run off the surface of the lawn rather than soaking into the soil.
Some common situations where wetting agents for lawns are used include:
- Dry patches across areas of the lawn, even after watering
- Tackling water-repellent soil
- Uneven water distribution
- Water conservation
While using a liquid soil-wetting agent could benefit your lawn, you must first understand how to maintain your garden using everyday watering techniques.
Applying a wetting agent during warmer months
Applying a wetting agent to your lawn during warmer months can provide several significant benefits. Firstly, it improves water penetration and distribution in the soil, allowing water to reach the root zone more effectively. This is crucial during hotter periods when evaporation rates are high, and water can quickly be lost from the soil surface.
Secondly, a wetting agent helps to reduce water runoff, maximising the efficiency of watering and minimising wastage. By preventing water from simply running off the lawn, more water is retained for the grass to utilise.
How can a wetting agent help with water consumption?
Hydrophobic soils repel water, and the water runs off the surface or simply pools and doesn’t absorb. It is a common problem, especially in sandy soils, but can affect many soil types that have not received regular water or are compacted.
Wetting agents are like a detergent or surfactant that reduces the surface tension of the water helping it to soak in.
What is hydrophobic soil?
Hydrophobic (literally “water hating”) soils are those that repel water. These soils cause water to run off or pool at the surface rather than being absorbed, which can cause serious problems for your gardens and lawns. It is a common problem in sandy or older soils, and can also affect soils that haven’t been watered or fertilised regularly.
Soil becomes hydrophobic when organic matter decomposes, leaving a waxy coating on the soil particles. As long as the soil remains hydrated, this doesn’t cause too much of a problem, but long periods of dryness can expose the hydrophobic surface and stop the water from penetrating.
How do I fix hydrophobic soil?
Wetting agents can be used regularly on your garden and lawn to solve the problem of hydrophobic soil. Wetting agents act like a detergent to reduce the surface tension of the water, thereby helping it soak into the soil.
Wetting agents come in both granular and liquid forms. Granular wetting agents are best for garden beds and pre-lawn installation, as they can be mixed into the soil. Liquid wetting agents can also be used on garden beds and existing lawns. For liquid wetting agents, we recommend a hose attached bottle product, then you simply attach it to your hose and water the product in.
Common concerns wetting agents can help with
What is the best method for watering a lawn?
Use an irrigation system or sprinklers on a timer for all lawn types, as this encourages a more even spread of water across the area and healthy root growth for your grass.
Hand watering with a hose doesn’t tend to distribute water evenly enough and is something to keep in mind.
If your lawn still has dry patches or it looks like the water is not being absorbed, a wetting agent may be the best next step.
How often should I water an established warm-season lawn?
An established warm-season lawn requires minimal watering. Most established lawns and plant growth survive on natural rainfall alone.
From October to March, you will likely need to water it once a fortnight to keep it healthy and green. Less frequent deep soaking encourages the lawn’s root system to grow deep into the ground, further strengthening its drought tolerance.
How do you know you have watered enough?
Set your sprinkler or irrigation system to run for about 20–30 minutes in the early morning or after dusk. After watering, simply stick your finger into the lawn and see whether it feels wet below the surface. If it does, you know it has received enough water.
If you notice your lawn is not absorbing the water over a long period of time, consider using a wetting agent.
What are the signs that my lawn needs a wetting agent?
Your lawn needs a wetting agent if:
- The colour of the lawn gets lighter even after regular watering and soaking.
- You leave footprints when you walk across the lawn (the ‘footprint test’ – a healthy lawn will generally bounce straight back).
- It dries out and feels crunchy underfoot (this generally only happens in the warmer months).
Finding the best soil-wetting agent for lawns
A wetting agent should typically contain specific ingredients that enable it to effectively reduce surface tension and improve wetting and spreading properties. The key ingredients commonly found in a wetting agent formulation include:
- Surfactants - responsible for lowering the surface tension of liquids and enabling them to spread quickly.
- Penetrants - help to break down hydrophobic barriers on surfaces.
- Stabilisers - ensures the longevity and effectiveness of the wetting agent
- pH adjusters - may be included to optimise performance in varying environments.
At Lilydale Instant Lawn, we stock Lawn Soaker the ultimate wetting agent for Melbourne lawns. Apply Lawn Soaker at the beginning of December, at the same time as your summer slow-release fertiliser. This is a fantastic way to prepare your lawn for the hot temperatures of summer, helping ensure that the water you apply to your lawn is used effectively by the soil.
Applying a wetting agent at the beginning of the summer season is a good addition to any lawn maintenance program.