Garden design
Micro Climate Control
By ‘micro climate’ I mean the unique mini climate of a single garden. For more information see Micro Climate in the Climate section.  The micro climate of a garden can be altered by what you plant, build or remove in your garden. There are a number of things you can do to change a garden’s micro climate.

Trees as heat banks in winter and shade in summer
Planting trees, especially evergreens, will reduce the extent and severity of frosts in Winter. This is because on still frosty nights they prevent the warm air from rising by trapping it under the leaves and within the body mass of the tree, which keeps the temperature just that little bit higher under and immediately surrounding the tree then nearby areas without trees. Trees also shield the ground from direct sunlight in summer and act as wind breaks.

Paths and Walls as Heat sinks
Photo of bathtub pond inside a greenhouse.
Bathtub pond inside a greenhouse.  Ponds act as heat banks, storing heat in from the sun during the day and giving it off at night or when the weather turns cool.
Materials such as concrete, brick and gravel used as paths and the walls of buildings(especially brick walls) will absorb heat from the sun during the day and release it when the air temperature drops at night or when the weather cools down. They also reflect some heat and light.  Adding paths and walls or simply putting more rocks in your garden will raise the average temperature in  your garden.

Ponds as heat sinks and coolers
Like concrete paths and brick walls water also acts as a heat sink, but water can also cool your garden on hot days by acting as a natural evaporative cooler.  Warm air moving over a the water of a pond on hot Summer days will be cooled, which will cool the area immediately around the pond.

Hedges and Fences as Wind and Frost Barriers
On frosty nights hot air rises and cold air sinks to the lowest point. In the country a hedge row or solid fence halfway across a sloping field can trap the cold air on the slope above.  Which means the frosts will also tend to settle there, leaving the lower slope relatively frost free. This also applies for larger urban blocks.  By having hedges and fences across the slope of your garden it is possible to alter the patterns where frosts settle. Hedges and fences also can act as wind barriers, reducing the heating and drying effect of hot summer winds.

If you talk a walk around your garden when there has been a mild frost you will be able to work out where the main frost points in your garden, which will give you an indication of where to place such barriers.