Mini-weather Patterns and Microclimates

Placing plants appropriately to take advantage of advantageous locations means being aware microclimates.

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  • Topic: Garden Design
  • Author: Mary Ann Walz
  • Keywords: Microclimates, hot spots, wet spots, cold spots, windy spots,, Garden Design, gardens
  • Date: March 2005

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Have you ever wondered why the fruit, flowers and vegetables in your friend’s garden mature so much earlier than yours? It might have more to do with microclimates than her green thumb.

Placing plants appropriately to take advantage of advantageous locations means being aware microclimates—those little areas on your property that are cooler, hotter, drier, moister, milder, or more severe than the greater part. They are your own localized weather patterns, and gaining knowledge of these areas helps extend the seasons in your garden.

Weather Patterns

Geographical features such as mountains, valleys and canyons greatly influence rain and snow amounts as well as wind patterns. The same ideas can exist in your garden, either by creating them or working with existing conditions.

Wind

Test for prevailing winds by placing some stakes around with ribbons tied on top. In areas with lots of turbulence, make sure plants that don’t like wind go elsewhere. Wind breaks—hedges, trees, trellises—help in slowing the wind and greatly affect the gusts that go through your property.

Cold Air

Meteorologists use the term “cold-air drainage” to describe cold, dense air that sinks along a hillside or mountainside and spreads along the floor of valleys. This process of occurs in the evening after sunset and forces the naturally cooler air of higher elevations down, keeping the valley cooler during night hours.

If your garden has these pressure areas—at the bottom of slopes and along fences that trap cool air—place cold-hardy plants here. They’re better able to withstand sudden drops in temperature.

Frost Zones

To extend the growing season for fruit trees and berries, use the natural conditions of slopes. Many commercial vineyards are planted on the slopes of mountainsides where first frosts occur later, thus extending the growing season.

Sunbelts

These are areas near south and west facing walls/large rocks and next to areas covered by pavement that are warmed by heat radiated from these heat-absorbing masses. Use these areas for plants that are heat lovers or need a longer frost-free spring growing season.

Living at a high elevation in USDA zone 4, I am especially fond of those few hotter microclimates. These are against the foundation on the south side of the house. I’ve enhanced the heat by adding some large rocks that will absorb even more heat. In one of these microclimates, I’m growing several varieties of Lavandula angustifolia that is typically hardy only to zone 5. Take advantage of south and west facing areas in the garden for plants that like a lot of heat.

Moisture Pockets

At the edges of large rocks and paving, under canales or downspouts, and on the north or east sides of structures, moisture is usually retained for a longer period of time. These areas are good for plants that are not extremely drought tolerant. I’ve found that I seldom have to water plants in some of these moister microclimates.

I think my favorite example of a special microclimate was at my previous residence in Santa Fe. I had spread compost on a bed on the north side of my house. In that bed, under a canale, a nectarine tree sprouted. It grew quickly and produced great crops of fruit. It got extra moisture from the roof runoff, its roots grew under a gravel pathway that remained moist, and the north aspect kept the tree from budding out too early in the year so the blossoms seldom froze.

The key to finding special microclimates is observation and being aware of how plants differ in the various spots in your landscape. Once you’ve identified them, use plants that like those special areas.