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How to retain moisture in soil

Retired Team Member
Retired Team Member

How to retain moisture in soil.jpg


Improving your soil's water retention can help ensure plants remain healthy. It can also help keep your water bill as low as possible. 


We asked garden experts for their top tips on how to help soil retain moisture and keep your garden thriving, even in warm weather.


Know your soil type

The key to a thriving garden is to have healthy soil, according to Melissa Boyd, Bunnings team member and garden expert.


"Good soil is crucial to successful growing," says Melissa. She advises that gardeners need to understand what their soil is comprised of and how it retains moisture before trying to improve it.


For example, clay soils can suffer from poor drainage, which sees them become a sticky mess when wet, or rock hard when dry. 


Sandy soil can also struggle to hold moisture and nutrients, according to Michelle Hughest (@mich1972), Bunnings Workshop member and garden expert. 


“Here in Perth, we have very hydrophobic sandy soil,” Michelle says. “The sand grains have a waxy surface which makes it hard for water to absorb into the ground. The water will just pool on top of the surface, making it difficult for the plant’s root system to absorb water.” 


You can check if your soil is hydrophobic or water repellent. The Bunnings team suggests using a watering can to pour water across your soil in the guide How to improve sandy soil. If the water just pools on top of the soil, your soil is water repellent.


Check out the guide How to determine soil heath by horticulturalist @Noelle for more advice on improving your soil quality.


Use soil wetting products and organic matter


If you have dry sandy soil, Michelle recommends using soil wetting products regularly to help retain moisture. These products, available in granular, liquid concentrate or hose-on form, can dramatically improve water penetration. 


“Soil wetting agents help by penetrating through the waxy layer, enabling water to be absorbed throughout the soil,” she explains. "Apply the wetting agent as per usage instructions, depending on how much the sand resists water. I recommend applying it throughout your garden and lawn at the start of spring and a couple of times during the hot summer months. You may apply it more frequently if you live in places like Perth which are on sandy plains." 


Melissa adds that “wetting agents and water storage crystals are especially useful for ferns or any hanging baskets that tend to dry quickly”.


She explains that water crystals have the capacity to hold almost 400 times their weight in water, enabling them to create a “constant and comfortable level of moisture in the soil”. This also makes them ideal for use when you are unable to water your garden regularly and during extremely hot or cold periods.

If you have dry clay soil, you can add sand, organic matter and gypsum to help them retain more moisture.


"Clay-based soils have poor drainage and can lack organic matter, so it's essential to take steps to fix this first," says Melissa. 


For more advice on helping clay soil become more absorbent, check out our Best Advice article How do you improve clay soil?




Both Melissa and Michelle say mulching can go a long way in helping your soil retain moisture.


Mulching aids in water penetration, slows water movement and reduces runoff.  It also feeds the soil as it breaks down, improving soil quality.

“Mulching regularly can also prevent harsh heat and winds from drying out your soil and inhibit weed growth in beds and around tree bases,” Melissa adds.

The Bunnings team shares tips on how to mulch in the guide Mulch and how to use it.  


Choose the right pots


The type of pot and its drainage system can also impact your soil’s ability to retain moisture, according to Michelle.


“Potted plants can dry out to the point where you can see the potting mix has shrunk and pulled away from the sides of the pot,”  Michelle says. “As you water, you can see how the water runs down the sides of the pot, not penetrating into the root system.”


Melissa recommends using self-watering pots to retain moisture as they typically hold water in the bottom of the pot, keeping the soil cool and from drying out.


“I would even consider the colour of the pot as darker coloured pots may absorb heat faster and make the soil drier,” she adds.


The Bunnings guide How to choose the right pot includes more handy advice.

The Bunnings Workshop community is here to assist if you need more help with improving your soil's health. Don’t hesitate to ask a question

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