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Know your microclimate

By Lawrie Smith AM

You really do need to know your microclimate. It has the most significant physical influence on the planning and design of any garden. Microclimate refers to the multiple ways that the broad regional or macroclimate is modified by the specific conditions of a much smaller site.

Essentially microclimate is the combined influence of the various aspects of the natural environment that physically impact on a particular site – sun, rain, air movement, vegetation and soils.

Once you know the microclimate patterns of a site, it is possible to use them as constraints or opportunities to influence the planning and design of the garden.

These are some the more important attributes of microclimate that have an influence on any garden, the planning and design process, the physical and functional characteristics, and the ongoing establishment procedures.


Knowing the exact direction of north is absolutely vital because this coordinates all of the other physical influences that impact on the planning and design of the garden. Place a north point prominently on every drawing.

Sunshine and shadow

Microclimate, the predominant influence on every site, is generated every day of the year, by the changing light and heat of the sun, and by the modifying effect of shade.

Understanding the changing seasonal patterns of sunshine and shadow moving across a site, and using them as design tools, will influence and define garden planning, layout and design.  It will also assist to simplify appropriate species selection, plant establishment, and ongoing garden maintenance.


The intensity, frequency and period of rainfall is the next most important garden influence. Rainfall is generally positive, but in extreme conditions can become destructive.  Diverting, absorbing, collecting, and storing surface water can ideally maximise sustainability, and also bring interesting designed landform to a garden.  Similarly planning for treating excess stormwater environmentally, can contribute positively to garden design.

Air movement

Air movement can variously cool, damage, dry, heat, freeze, and increase evaporation. Knowing the direction, frequency and speed of air movement across a site will suggest specific garden planning principles that invite cooling breezes and block damaging, drying winds.


Trees, shrubs and groundcovers all have varied positive influences that contribute to garden design. They are not just attractive botanic elements.  Foliage density insulates soil from drying sun exposure, and reduces radiated soil/air temperature. Leaves release water vapour into the air through transpiration, adding moisture and humidity.

high canopy to grow a native garden in shade
Bev Fox garden, image Lawrie Smith

Soils and surface treatment

Terra australis garden, image Ben Walcott

Soils are the basic geological matrix which provide structural support, release nutrients, and influence all plant growth.  Soil types have varying effects on microclimate. Soil composition defines the ability to absorb, retain or shed water, and affects available soil moisture levels. Sandy soils, other coarse, loose, and dry soils are subject to high maximum and low minimum surface temperatures. Pale coloured soils and mulches reflect more heat than dark tones, so remain cooler.

You really do need to know your microclimate!

What does a microclimate analysis drawing look like?

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