Newsletter Articles
Microclimates in the Garden: How to Create and Use Them
By Richard Flowers, ACCNP-Green Thumb Nursery-Ventura
Every yard has warmer and cooler pockets shaped by walls, slope, sun, and wind, and the wrong spot can scorch a tender plant or expose it to frost. You create a helpful microclimate by using those features on purpose: a south-facing wall for warmth, afternoon shade and mulch to ease heat, and a sheltered higher spot away from frost-prone low ground.
Quick answer: A microclimate is a small zone in your yard that runs warmer, cooler, windier, or more sheltered than the rest, and you can use it to protect plants.
- Map your yard’s sun, shade, and wind before planting, since each spot behaves a little differently.
- For a warm spot, place frost-tender plants against a south-facing wall or under an overhang that blocks the open night sky.
- For a cool spot, shade heat-sensitive plants from afternoon sun and spread mulch to keep roots cooler and soil moist.
- Keep tender plants out of low areas where cold air settles and frost forms first.
- Water containers and beds near walls or pavement more often, because those spots dry out faster.
| Feature | Effect | How to use it |
|---|---|---|
| South-facing wall | It catches more sun and stores heat, so it stays warmer than open ground. | Place frost-tender, heat-loving plants here, and water them a little more often since the warm soil dries faster. |
| Low spot or dip | Cold air sinks and collects there, forming a frost pocket that chills first. | Keep tender plants out of it, and save low spots for hardy plants that shrug off light frost. |
| Shade from a structure or tree | It blocks strong sun and keeps the ground beneath it cooler. | Use it to shelter heat-sensitive plants from hot afternoon sun. |
| Pavement or patio | It absorbs and reradiates heat, acting as a small heat island. | Expect nearby plants to run hotter and drier, and water them accordingly. |
| Exposed, windy spot | Open, high areas catch drying winds that pull moisture from plants. | Add a windbreak of shrubs, or plant wind-tough species in these spots. |
What Is a Microclimate
A microclimate is a small area where the local climate differs from the surrounding landscape. University of California ANR describes it as a local atmospheric zone where the climate differs from the area around it, which is why one corner of a yard can be noticeably warmer, cooler, or windier than another.[1] Most yards hold several microclimates at once, created by the mix of walls, slope, paving, and plants, and learning to read them lets you put each plant where it will do best.
What Creates Microclimates in Your Yard
Microclimates come from the way sun, structures, slope, and wind interact across your property. University of California ANR explains that south-facing areas receive more light and heat, while the north side of a wall or slope stays shadier and cooler, and that a house absorbs heat during the day and reradiates it at night, with paved surfaces acting as heat islands that soak up and release the sun’s energy.[1] The same University of California ANR guidance notes that hilltops are more exposed to drying winds, that trees and shrubs create shade and serve as windbreaks, and that a dense canopy can trap heat at night and moderate temperatures.[1] Slope matters too: Penn State Extension notes that cold air collects in low areas, which can get a light frost even when areas uphill stay frost-free.[2] For help placing plants around sun and shade, see our guides to keeping plants healthy during a heat wave and SoCal shade trees that keep their leaves.
Creating a Warm Microclimate for Frost Protection
To shelter frost-tender plants, put them where your yard naturally stays warmer and loses less heat on cold nights. Penn State Extension points out that stonework and masonry store heat, creating warm spots near buildings or rock walls that suit heat-loving plants, though the warm soil there dries out much faster.[2] Overhead cover helps as well: Colorado State University Extension explains that radiation frosts occur on calm, clear nights that lack the cloud cover to hold in heat, which is why a spot under an eave, overhang, or tree canopy loses less warmth to the open sky.[3] Put those together by planting tender plants against a south-facing wall, tucked under some overhead cover, and away from low frost pockets. Our guide to helping outdoor plants survive winter in SoCal covers more cold-season steps.
Creating a Cool Microclimate to Reduce Heat Stress
To ease heat stress, shade sensitive plants from strong sun and slow the soil from drying out. Oregon State University Extension recommends suspending shade cloth on the sunny side of sensitive plants, which it reports can keep them up to about 10 degrees F cooler, along with mulching to reduce soil evaporation and relocating young or potted plants to a shaded location during extreme heat.[4] University of California IPM gives similar advice for heat injury: apply organic mulch to the soil, shade the sides of containers and planting boxes, irrigate adequately, and choose species well adapted to the site.[5] Containers need extra attention in a hot microclimate, because Oregon State University Extension notes that hanging baskets and container plants dry out more quickly than plants in the ground,[4] and Clemson Cooperative Extension adds that they may need daily or even twice-daily watering.[6] For watering strategy in hot, dry spots, see our guide to water-wise watering, and for tough, sun-loving choices, our list of heat-resistant plants.
Not sure which pockets of your yard run hot, cold, or windy? Stop by any Green Thumb Nursery and our team can help you match plants to the microclimates around your Southern California home.
Microclimate FAQ
How do you create a microclimate to reduce heat stress in a garden or rooftop?
Shade the plants and slow evaporation. Oregon State University Extension recommends shade cloth on the sunny side plus mulch to cut soil drying, and moving potted plants to a shaded spot in extreme heat.[4] University of California IPM adds that shading the sides of containers and irrigating adequately help limit heat injury, which matters most on a hot rooftop or patio.[5]
How do you create a microclimate in your garden?
Use the features already in your yard. University of California ANR notes that south-facing areas and walls run warmer, north sides stay cooler and shadier, and trees and shrubs create shade and windbreaks, so you place each plant where the conditions suit it.[1]
What are some examples of microclimates?
Common ones include a warm south-facing wall, a shady north side, a cool low spot where frost settles, and a hot strip beside pavement. University of California ANR describes these differences, including paved surfaces that act as heat islands.[1]
What is a frost pocket and how do you avoid it?
A frost pocket is a low area where cold air collects and frost forms first. Penn State Extension explains that cold air sinks into low spots, which can frost even when uphill areas stay frost-free, so keep tender plants on higher or sloped ground instead.[2]
What plants grow well in a southern exposure?
Sun-loving and heat-tolerant plants do best there. University of California ANR notes that south-facing areas get the most light and heat, making them the right place for plants that want full sun and warmth rather than shade-lovers.[1]
Sources
- [1] University of California ANR, Microclimate (The Real Dirt): ucanr.edu
- [2] Penn State Extension, Getting to Know Your Yard’s Microclimates: extension.psu.edu
- [3] Colorado State University Extension, Frost Protection and Extending the Growing Season: extension.colostate.edu
- [4] Oregon State University Extension, How to Protect Yourself and Your Plants During Extreme Heat: extension.oregonstate.edu
- [5] University of California IPM, Thermal Injury or High Temperatures: ipm.ucanr.edu
- [6] Clemson Cooperative Extension, Hanging Baskets and Window Boxes: hgic.clemson.edu
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