The previous post looked at two different pieces of information that can greatly benefit you in your plant selection: plant hardiness zone and your growing season. This is important information for gardening, but it’s not everything you need to know. These tools are limited because they use data from a network of climate stations across the country. Your local weather station may be many miles from you, and it’s unlikely to have the exact same climate as your garden.
This brings us to the last part, but perhaps most important, part of the understanding your climate: your personal and entirely unique gardening climate.
Microclimate refers to differences in climate that are founds at very local levels. Just a few examples of influences on microclimate are:
- large bodies of water on nearby land—such as the “lake effect” that we see near to the Great Lakes
- pavement, buildings, and the built environment—which can create warmer conditions though the “heat island effect”
- the direction that a piece of land faces (aspect)—such that south-facing locations tend to be warmer (in the Northern Hemisphere)
- landscape patterns that affect air movement—such as cold air drainage that can lead to “frost pockets”
Microclimates can be extremely tiny. Even in your own yard, you might observe that more tender plants can grow near the south side of your house because the building helps collect and radiate heat. Over time, the observant gardener can locate cold spots (and wet spots, windy spots, sunny spots, and all manner of spots) within a single garden. My vegetable garden is located on the slightest south-facing slope, but it’s enough of a difference that I can be planting early greens in the higher (by 6 inches) and drier end of my garden while the other half of the garden—only 20 feet away—stays stuck under snow for an extra two weeks.
Pay attention to your garden to discover these microclimates. There are many different clues when you look up close. Spring and fall can be particularly good for discovering where cold air or frost settles, and for seeing which parts of the garden “wake up” first. You can use your hands (and even a meat thermometer) to find places where the soil heats up (and probably dries) more quickly, compared to where it tends to stay cold. As you identify these places, be sure to note—actually write them down if you can—where they occur, so you can adjust the plants to more suitable locations as you need to.