Officially, a Micro Climate can be as small as a space of a few square feet in the garden to the inland effects of a large body of water, but for most of us creating our gardens, it is a place within our property that dictates different conditions for planting choices.
Often cited as a technique to grow less than hardy plant selections, or fruits for best production and other planting position plans, Micro Climates are variation within your own property. They are the areas that are more sheltered or less, facing the prevailing winds, where frost pockets show up, or where the the buildings and the sun create warm spots. You can use these places created by the topographyshape of the land, the landforms of hills and valleys, etc. or buildings and trees to decide what landscape features to include.
Tombstone Creek Topography Map
One of the ideas I always liked was that of a sheltered garden seat for early spring enjoyment of the garden. Often, when spring invites us outdoors with blue skies and sunshine, the temperatures are just a bit chilly, and the winds can make actually sitting in the garden too cold to sit for long. Not so, in a cozy little corner protected by hedges or a building. A southern facing nook sheltered from prevailing wind (those are South-westerly in my part of the world) is perfect for a garden seat, taking in the birdsong and floating clouds with a morning cup of coffee in hand.
Let’s list some possible micro-climates and how you may put them to use for your own home garden planning.
Leeward Microclimate
Showing leeward side of a building
I use the leeward side of my home to plant roses, the pyracantha, and where I enjoy a small garden pond.
The Windward Side
The opposite of the leeward is the windward. For me, that means the west. The Southwesterly winds prevail for most of the year, and the majority of storm systems come from that direction as well. These winds can pound against everything in their path, but also provide a cooling respite from Midwest midsummer heat, so they do have their redeeming qualities.
I plant a windbreak of shrubs and trees on that side of the land. It is important to make sure that perennial plantings are hardy enough to take temperatures and the conditions in the open, including the trait resistance to desiccating winds. Drying wind kills more plants than simply the chill of temperature drops. Some gardeners sheath their evergreens in burlap to protect against such problems.
Sheltered Nooks
As I said, this is my favorite place for a garden seat, but the changing seasons also change the definition of what makes a sheltered spot. What do we wish to find shelter from? The wind and cold temperatures? Or bright sun and withering heat? Take your pick and find a space that filters out or modifies the offending effect.
Shady spots that lessen the impact of heat and sunshine are most needed in hot climates or summertime conditions. Sunny nooks for shelter from cold winds and less than comfortable temperature, a good place to protect plants from cold, wind, and harsh frosts.
Several spots, for seasonal pleasure, Â can be set up with seating or even as a landscape feature, like the firepit are we created in our own yard.
Shelter is provided in different ways. Trees, shrubs, and fences protect, but allow airflow, and trees even provide it. Buildings and solid walls create a barrier to winds, and a warmer climate on the sheltered side; their inward corners catch and collect warmth.
Frost Pockets
Whenever I planted fruit trees, the advice I read warned about frost pockets. Frost pockets are where cold air accumulates and is trapped  in a pool of colder temperatures than the surrounding land.
Other names for these “frost hollows” or “cold pools”, and can be quite a bit colder freezing sooner and thawing later because of the way it traps the colder air. Extended frost periods are damaging for plants in growth or bloom, hardy plants go into dormancy to protect themselves from the way frost temperatures rupture plant cell walls.
Usually created by dips and hollows in the land, air “drains” into these spaces much in the way that water does. Observing where there are pockets of fog, or where frost hangs on can clue you into the places where a frost pocket might be a problem for fruit production or a vegetable garden.
Frost hollows are created by the same things that create a sheltered nook, if the effect is to collect cold air, instead of warm.
Information for UK gardeners, on frost and frost hollows UK Frost Information .
Barriers And Garden Conditions
An amazing English garden hedge at Powis Castle
If you have solid walls or not, you surely have a building or two. Buildings affect more than wind, and it is important to check for dry spots. Notorious for arid conditions is the space under the eaves of your roof. Many homeowners plant their foundation plants much too close to the building. Consider the moisture levels of areas in proximity to solid walls and buildings.
Barriers of all sorts also impact the amount of snow dropped and drifted in your yard. Does a fence cause snow to pile in the driveway? Check the climate effects of your barriers throughout the year, sometimes the adjustment of a snow fence (temporary fence for winter) or some other change is necessary.
Deciduous trees and shrubs give the most forgiveness in creating a barrier due to losing their leaves. That also means a more transitional impact on the microclimates you are trying to create. Evergreens give the best protection against winter winds, if that is your intention.
