Microclimates Are Local Climate Conditions In Small Areas Or Parts Of A Garden, Causing Better Or Worse Growing Conditions For Plants, Gardeners & Allotment Plot Holders.
A microclimate refers to the climate conditions within a relatively small and localized area that may differ from the surrounding, larger climate. This variation in climate can be influenced by factors such as terrain, vegetation, water bodies, and human-made structures. Essentially, a microclimate represents a small-scale atmospheric environment that differs from the broader regional or macroclimate.
Various factors contribute to the development of microclimates. For example, urban areas may have warmer temperatures compared to surrounding rural areas due to the heat-retaining properties of buildings and pavement (urban heat island effect). Similarly, the presence of bodies of water, such as lakes, rivers, or even the sea, can moderate temperatures in the adjacent areas. Vegetation, topography, and altitude can also play crucial roles in shaping microclimates.
As gardeners I know we should pay attention to microclimates within our gardens. We need to consider factors like sunlight exposure, wind patterns, and shelter provided by structures or plants.
And we often need to consider modifying the microclimate in our gardens and allotments. But how can we modify our microclimates?
How To Modify Your Microclimate
The Victorians were good at this, especially in the walled gardens of the great houses. And that’s their first example many of us recognise as a microclimate modification. The walled garden, where the climate within was so different to the climate outside. The high walls slowed the wind and were a sun trap enabling soft fruit such as peaches and grapes. The brick or stone walls would warm up during the day and slowly release the suns warmth during the cooler hours. Night temperatures were boosted and crops, that wouldn’t otherwise thrive, prospered in the English walled garden.
But being a wall had its disadvantages as well. Because when it was cold the walls could trap the cold air and the crops would get frosted, especially at the lower reaches where the garden was on a south facing slope. When the cold air descended to the lowest point of the garden and settled it spelt damage to soft growth.
But the Victorian Head Gardeners had a trick or two to overcome this problem. The installed frost doors at the lowest point in walled garden. On frosty nights they opened the doors to allow the cold air to escape further down the slope and away from the walled garden. And to ensure rabbits, deer etc didn’t enter via the open door, they placed a wire mesh frame over the doorway!
Most of us aren’t lucky enough to have walled gardens. But we can still modify air flow through the garden.
Solid fences and walls can cause turbulence, which can be as bad as a strong wind. An alternative is a permeable wind barrier. A slated fence panel, perhaps a hazel livestock fencing panel, can reduce wind flow rates and prevent a lot of damage. They can be used around greenhouses or polytunnels with great effect and no shading.
Alternatively grow a few strategically placed shrubs, bamboos or similar where you want to slow the wind, provide shade or screen for other reasons. A shade providing screen can greatly decrease the rate at which beds dry out and ensure watering is not needed.
There is of course the question of aesthetics to be considered in all this. In the flower garden it is perhaps easier as plants can be trained over structures. Whereas in the veg garden it is harder unless we accept the visual intrusion.
For many years farmers have made use of physical structures. To prevent Fen blows, that can strip the soil from a field in hours, they planted tall willow field dividers that sweep across parts of the Fen landscape. What you might have missed are the low level use of straw to prevent blows. Between crop rows of strawberries, carrots or other crops they would strew straw which was then pressed into the soil with a disc coulter. This made the ends of the straw stand up and create mini fences, just a few inches high. It was an ingenious way to prevent wind erosion which has to be seen to be believed.
The following video shows the sandstorm proportion of a Fen Blow.
Another simple way to modify the climate is to use fleece or similar to protect crops from wind, pest and diseases. Single use plastic was the product of choice a few decades ago but today the woven fleeces are more popular.
In times past gardeners and growers didn’t consider the environment in the same way as today. Not only were single use plastic products common, but years before that the use of smudges pots in orchards was commonplace. Smudge pots were used to create heat and often a lot of smoke when frost threatened. The heat and low layer of smoke prevented the frost from descending and damaging blossom. Diesel oil was usually used to in smudge pots and very smudgy they were.
A later alternative was to use water. Fine droplets were sprayed in to the air where it apparently gave up its latent heat to the air as it froze, hence protecting the delicate blossom.
The above are just a few ways we can modify our microclimates. Sometime in the future I’ll add a few more methods that can be employed.
In gardening the elements always seem to transpire against us. But we can do a lot to overcome the problems if we understand how to control conditions and microclimates.
Of course one way to ensure conditions are right is to choose the best microclimate from the outset. For example, the plat farmers near me in East Devon grew crops on the cliff edge where frosts were unknown. Potatoes were planted in February!
Image attribution: Mikeman400 at the English Wikipedia, CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons
Tag: What Is A Microclimate?
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