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Health concerns around the Heat Island Effect

Updated: Jan 4, 2023

Australian governments have identified the Heat Island Effect in suburbs lacking greenery. Heat Islands are urbanized areas that experience higher temperatures than outlying areas. Structures such as buildings, roads, and other infrastructure absorb and re-emit the sun's heat more than natural landscapes. Highly paved areas around homes add heat and lessen rain getting into the soil.

What the scientists say

Scientists say the “urban heat island” effect, which can raise temperatures in urban areas by several degrees, could be a risk to human health as growing urban populations exacerbate the heating effects of climate change. Reports from the UK show increases in temperatures up to 14c degrees and in Perth, WA, some of the new areas are 4-10 degrees hotter than surrounding areas.

Small blocks with large houses with little space for trees or lawn areas get as hot as large open treeless plains.

Trees, shrubs, green roofs, vegetation and a cooling lawn can help reduce urban Heat Island effects by shading building surfaces, deflecting radiation from the sun, and releasing moisture into the atmosphere.

There is little climate change wisdom in having highly paved gardens trying to 'save water' while having to run your air-conditioning unit 24/7 during the summer.

Listen to horticultural and landscaping expert Darren Seinor talking about the Heat Island Effect and how to grow your oasis even on the smallest blocks.

Keep reading to find out how to 'save water' in your Heat Island refuge.

Cooling the exterior of your home will decrease the need for high usage of air-conditioning

The trees, shrubs and grasses we plant are natural cooling mechanisms – plants draw soil moisture up into their leaves, which then evaporates from the surface of the leaves and cools the air, much like an evaporative air conditioner.

Grass is cool underfoot, and through shade and transpiration, plantings create microclimates around homes and commercial buildings that provide lower temperatures. Leaving grass a little taller helps to retain water and encourages a deeper root growth.

The garden featured here in the photographs is an excellent example of a small area developed to cool in summer with trees for food and shade mixing with deciduous trees letting warming sunlight in during the winter months.

The residents of this home rarely use the air conditioner - even in the hottest summers.

Their alfresco area is shaded by small and medium trees, an array of flowering plants, ferns, small patches of long-cut lawn and two raised-bed vegetable gardens.

But this is going to cost a lot in watering isn't it? And what about my sandy soil - it won't grow anything!!!!!!

Protecting your environment by cooling the exterior of your home or office building you need to prepare your soil to support your plantings.

Sandy soils are hydrophobic.

Amending your sandy soil into a mineral-rich loam with Soil Solver’s Clay Plus Minerals you can reduce your watering requirements by 50%.

Soil Solver® has the only gardening product meeting Kaolin clay Australian Standards enabling home-owners and business premises to economically shade their premises, growing healthy plants to cool your environment.

This is because Soil Solver's unique high-grade Kaolin clay has particles less than 2 microns. This means it covers the sand particles and holds them along with humus, thus linking the 3 components of healthy soil to form 'peds' of soil. It holds minerals and water enough to stop them leaching, but, unlike other silicas, 'clay' and wetting agents on the market, allows the vital moisture and minerals to be plant available.

Ok, but I don't have sandy soil. I struggle with clay soils what can I do?

The most important growing factor within your soil is minerals. Just like our own bodies, without the correct balance of minerals, we can't take up all the benefits of nutrients.

Clay soils are also very mineral-poor. Soil is a major source of nutrients needed by plants for growth. The three main nutrients are nitrogen (N), phosphorus (P) and potassium (K). Together they make up the trio known as NPK.

Other critical nutrients are calcium, magnesium and sulphur. Plants also need balanced quantities of iron, manganese, zinc, copper, boron and molybdenum, known as trace elements because only traces are needed by the plant. The role these nutrients play in plant growth is complex and is the difference between plants which just survive and those which give lush foliage and healthy blooms and edibles. These are all blended in Soil Solver® products.

Compost Plus Minerals is Soil Solver's top selling mineralised compost mix with outstanding results on any type of soil. See our Compost Plus Minerals page for details.

Hints to avoid the Heat Island Effect:

  • Make a plan of your garden area confirming how the sun travels over your property throughout the seasons.

  • Prepare your soil by using Soil Solver® products to reduce watering requirements and ensuring your soil and plants get the required minerals and nutrients

  • Plant small to medium fruit and deciduous trees

  • Design small patches of long-cut lawn around the garden, especially around doorways and windows

  • Mix and match your plants between edibles and flowers, ferns and shrubs

  • When you have it all right - sit outside enjoying a refreshing beverage in your cool area and think how clever you are!! Cheers.

PS. It also works for those with large areas needing cooling.....

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