You may not be aware that there could be a plethora of different climates on your property. Some of those climates are ideal for gardens and some are not. Knowing where the best climates for growing plants are within your environment could be the difference in having a garden that lasts long into a growing season and a garden that does not.
What Are Microclimates?
What we are talking about are microclimates, climate that is restricted to an area that is different than the climate of the surrounding area.
A number of variables affect a microclimate. They include:
- Sun exposure
- Trees and shrubs
- Paved surfaces
These variables affect temperature, moisture, sunlight, soil, terrain, and wind exposure.
Perhaps the one variable that affects a microclimate the most is sun exposure. Sun exposure differs for areas of your property that face north, south, east and west.
Areas that face north experience shade all year round. So the soil of this microclimate is soggier than areas that face south, east, or west. Areas exposed to the north are the last to warm up in spring and the first to cool in the fall. The difference between northern exposure and southern exposure is greatest in the winter. That’s when structures create long shadows the block the sun. That’s why snow on walkways and land persists. However, this area is cool during the summer.
Areas that face south get more sunlight and are warmer than other areas of your property. The warmth increases soil evaporation resulting in drier soil and causing plants to lose water vapor. These areas warm up earlier than other areas of your property in spring and are ideal for planting bulbs that bloom several weeks earlier than they would in northern exposed soil. However, early blooms can be a problem for plants that can’t withstand frost. Southern exposed areas remain warmer in the fall allowing for plants to last longer into the growing season.
Areas that face east receive sun during the morning hours all year round. So the area is not as hot on summer afternoons and evenings and the soil remains moist. Plants that thrive in moist soil and partial sun are best located in eastern exposed areas. Plants that grow in eastern exposed areas are also protected from winter winds and cold temperatures.
Areas facing west experience shade in the morning hours and low angle sunlight in the afternoon. In the summer these areas are hot and the soil is drier. However, in spring and fall the sun is warm, but the nights are cold, a condition that can cause harm to plant tissue and cause cracks in the bark of young trees or the blackening of newly formed leaves and stems. These areas are ideal for hardy plants that favor dry soil and warm temperatures.
Trees And Shrubs
Trees and shrubs provide shade, allowing plants that grow in full sun in cooler climates to thrive in warmer climates, too.
Structures including fences and walls also affect sun and shade. Moreover, materials and colors of close structures can affect temperature. Dark colors absorb and hold heat and releases it after sundown. Light color structures reflect daytime heat and light onto plants.
The south exposed exterior wall of a house gets first sun and remains warm all day. So plants that may not thrive in cold zones, can flourish when planted near a southern exposed wall.
The west-facing wall of a house gets early morning shade and then a lot of afternoon sun. The area gets even warmer due to the radiated heat and light reflecting off the wall. Plants that tolerate heat and light of the afternoon will thrive in this setting.
But in the fall and winter, the morning sun arrives earlier and the extra heat provides a garden bed 5-10-degrees more warmth than other areas of your property on a sunny day.
The east-facing exterior wall of a house offers the morning sun and afternoon shade creating an ideal condition for plants that would normally not tolerate heat.
A north facing exterior wall of a house gets less direct sun that results in more moisture and less evaporation for plants.
Paved Surfaces, Rocks and Bricks
Light-colored paved surfaces, rocks and bricks reflect heat toward plants grown next to them and transfers warmth to soil.
Slopes are their own microclimates. For example, warm air rises while cool air sinks and creates frost pockets. In this condition, air drainage is necessary. The soil tends to be rockier and course along the top of a slope. So this area drains well and holds less moisture. The steeper the slope, the drier the soil while at the bottom of a slope the soil will be soggier due to runoff and erosion from the top of the slope.
Slopes are also influenced differently depending on whether they face north, south, east, or west.
So take time to observe your property. Determine north, south, east, and west. Scrutinize the landscape for changes in topography and the location of structures, trees, shrubs, and paved driveway and walkways. If you know the affects of microclimates, then you know how to take advantage of what your property provides.