Microclimates are small areas in the garden that—by virtue of being sheltered, beside an object of high heat capacity, or otherwise exposed/unexposed—have a different set of conditions than what is typical for the biome at large.
An example of a microclimate is an area of soil covered by the roof of a house: The area remains dry because it does not experience as much rainfall, and it is slightly warmer because of the radiating heat from the dwelling. Therefore, this particular little microclimate would be a place in which a gardener in a cool, rainy biome (like mine), could try growing more arid-adapted, heat-loving crops. I’m trying a Jujube tree (Ziziphus jujuba).
Normally, gardeners in temperate zones seek out warmer microclimates, as they try to push their luck with hardiness zones. However, cooler microclimates—usually partially shaded places where water gathers—are sought after for folks living in arid zones or the tropics.
A microclimate can be both discovered and engineered. Usually, it’s a matter of simple observation. Cataloguing differential temperatures, soil moisture levels and sun exposures in different places throughout the day can aid in selecting the best sites for planting particular plant selections.
At Denmark’s Pometum (pictured above) are two microclimates. The most obvious one is inside the greenhouse, where the grape vines have their more Mediterranean climate. However, the space between the greenhouses is both sheltered and exposed to radiating heat from the structures, so it’s being used to grow a row of peach trees.
The herb spiral (pictured above) is a classic mode of working with microclimates. It uses the heat capacity of the building materials (bricks, stones, bottles, et cetera.) and a spiral drainage structure to cultivate arid-adapted herbs, such as rosemary and tarragon, on top and cool-, moisture-loving selections, such as dill and parsley, near the bottom.
Discovering or building these spaces in the garden requires attention to detail and a basic understanding of the variables at play. With proper plant and site selection, you can maximize the potential of every corner of your garden!
About the Author: Lynsey Grosfield is the founder of BiodiverSeed, a global seed swap network devoted to the exchange of self-harvested, organic and heirloom seeds with the goal of preserving maximum genetic diversity. Follow BiodiverSeed on Twitter.