A garden is filled with life both above the soil and below it. Plants and sub-cultures are developing within the soil and how well they develop depends a lot upon the microclimate in the garden.
All landscapes and gardens have various microclimates in them and it’s a climate within a climate. It’s why the hilltop is covered with snow and the valley only received frost on the same morning. A microclimate also explains why certain plants thrive in one area and die in another area of the same landscape.
Let’s understand and adjust microclimates in your garden.
Causes of Microclimates
Man-made features are often the cause of microclimates and it’s not always a bad thing. Roadways, walkways, or other concrete surfaces will increase the soil temperature and rain-water runoff for adjacent soil. New construction on a property can increase the amount of rainwater that collects in a nearby low-lying area.
The addition or removal of trees, shrubs, and other plant life will change the microclimate of a garden or landscape. Simply parking your vehicle in a different location over time will change the microclimate in the immediate area.
Work With the Microclimate
Understanding the microclimates within your garden will enable you to know which plants will grow best in each location.
For example, a slightly elevated garden spot that is in full sun all day is a bad location for planting a rain garden. The rain garden will constantly need to be watered and the plants will not perform their best because they are in a hot, dry microclimate.
Drought-tolerant plants will thrive in that microclimate and the rain garden will thrive in a shady, low-lying area that stays damp from rainwater run-off.
Most gardens have several different microclimates and each one provides different growing conditions for plants.
You and a neighbor will be in the same USDA growing zone, yet some plants will produce better in your garden and vise-versa all due to the microclimates within the garden.
Climates that have short summers can extend the growing season by planting crops near structures. The structures will cause the soil to be warmer and provide plants with protection from wind and light frost.
Hot, dry climates can reduce the heat of the soil and help it to retain moisture by keeping the soil covered with growing plants and/or mulch. Plant the garden on the east side of the property as this will give full sun to plants during the morning hours and provide them with a little cooling shade during the heat of the afternoon.
Each above-ground microclimate will have a matching sub-culture that is living below the ground. These sub-cultures are an important part of plant growth, development, and overall health.
Gardeners are aware of the value of earthworms to their garden and they are a part of the sub-culture that thrives in cool, moist soil. As the earthworms travel under the soil they leave behind tunnels that promote good airflow and water drainage. They also leave behind castings that improve soil fertility.
Hot, dry, compact soil won’t have the activity of earthworms. However, it will have a unique sub-culture that can survive in that microclimate. Sub-cultures will change, along with plant growth and production, when the microclimates are adjusted.
Adjusting the Microclimate
The conditions of microclimates are determined by plant orientation and exposure to heat, light, water, and wind. Many of these factors can be adjusted so you can grow healthier plants and select from a wider range of plants suited to your growing zone.
It is simply where the plant is located. The most ideal garden row orientation is north and south as opposed to east and west. When rows of plants point north and south, every row receives the same sunlight exposure during the day.
However, there are many variables within the landscape and north to south orientation for the entire garden is not always possible.
Adjust the sun exposure by planting the taller growing plants in a location where they will not impede the sun exposure of shorter plants. Some plants, like squash, will benefit from having a little shade in the hot summer afternoons. Plant orientation can be adjusted to provide that welcomed shade.
Exposure to heat
This can be adjusted by keeping the garden away from concrete surfaces, which absorb heat and radiate it back into the soil. Avoid using bricks, dark-colored concrete landscape edgers, and other dark, heat-absorbing material to create raised bed gardens unless you live in a climate with short summers.
The dark colors cause the soil to heat up faster in the spring and remain warmer longer at the end of summer for an extended gardening season.
Also use light-colored containers instead of black pots for container gardens in hot climates so the heat will be reflected, not absorbed, into the soil. Black containers are useful in cooler climates because they will enable soil to warm up faster so crops can be planted earlier.
Observe your garden
For a few days, watch your garden closely to determine where the sun hits the soil throughout the day. Place plants in spots that provide them with the optimum sun exposure for their development. A wide-open garden space may expose plants to wind and potential wind damage but that windy microclimate can be adjusted by
- placing growing containers around the garden perimeter or
- planting taller plants on the outside garden rows and
- shorter plants in the interior rows
Some garden spots are naturally dryer or wetter than others. Adjust the soil by
- incorporating organic matter into the soil so it can retain moisture evenly
- planting drought-tolerant plants in the dry microclimates and thirsty plants in the wet areas