What Are Microclimates, And How To Use Them In Your Garden

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In this article, you’ll discover what microclimates are and how to use them to improve your gardening success.

Learning to spot microclimates

If you’re a gardener, you’re probably familiar with agricultural zones, first/last frost dates, and plant hardiness. Knowing this information keeps you from trying to grow tomatoes outdoors in Ohio in December!

But you might not be familiar with “microclimates,” even though they’re all around you, ranging in size from small patches in your garden to multi-acre spaces.

This image was taken in the Santa Monica Mountains in California. Notice the north-facing slope (left) is covered in white-blooming hoaryleaf ceanothus, while the south-facing slope (right) is much less sparsely vegetated in completely different species of plants. What accounts for these differences? Microclimates. Image credit: By Noah Elhardt – Image taken by Noah Elhardt using a Sony DSC-s70 digital camera., CC BY-SA 2.5, Link

What are microclimates?

Microclimates are land areas that foster unique environmental conditions relative to the broader ecosystem where they’re located. For instance, microclimates can cause wide variance in soil moisture, humidity, sunlight, temperature, soil organic matter, and other factors.

Large microclimates

There can be large microclimates, such as an entire city (aka “urban heat islands”), a north-facing slope, or a valley that’s much cooler or more moist than the surrounding area.

Image credit: By Urban_heat_island.svg: TheNewPhobia derivative work: Alexchris (talk) – Urban_heat_island.svg, Public Domain, Link

Cities create large microclimates due to the “heat island effect.” For instance, we live about 10 miles from a city and it’s almost always a few degrees warmer in the city versus where we live out on the edge of the suburbs. It’s interesting to see the trees in the city start to leaf out in the spring 10-14 days ahead of ours due to the difference in climate.

And in the fall, our first killing freeze usually arrives three weeks BEFORE our friends who garden in the city!

Small microclimates

There can also be small microclimates right within your own yard or garden that offer unique conditions: warmer, colder, wetter, dryer, sunnier, shadier, etc…

Knowing the microclimates in your yard can make a huge difference to your success as a gardener. Selecting edible plants that prefer the unique conditions of a specific microclimate will mean healthier plants, better yields, and less human effort.

Selecting Plants for Your Microclimates

Here are some examples of microclimates and plants you could select for those climates:

Microclimate: Large rocks, driveways, and sidewalks

Do you have a large boulder, rock, concrete driveway or sidewalk in your yard?

These dense surfaces/objects absorb heat from the sun during the day and slowly release their heat at night, making the ground around them warmer (and potentially dryer if there’s not much rain). This means you could potentially extend the growing season of plants placed immediately next to them or put in plants that like more heat and dryer soil.

The large rocks on the front of this bed absorb a lot of heat on a sunny day, and radiate that heat back into the bed at night. This means the soil stays a few degrees warmer than in surrounding areas. Article: What are microclimates by GrowJourney — The large rocks on the front of this bed in our garden absorb a lot of heat on a sunny day, and radiate that heat back into the bed at night. This means the soil stays a few degrees warmer than in surrounding areas.

Microclimate: South-Facing House Wall

The front, south-facing exterior walls of our house get first sun and stay warm throughout the day. Certain plants that might not normally grow well in our Ag Zone due to it being too cold (example: pineapple guava shrubs) do fine when planted near these walls due to the additional heat.

We’re also able to extend our growing seasons for our annual plants in these edible landscape beds.

Microclimate: West-Facing House Wall

The west-facing wall of our house gets early morning shade and then gets blasted with afternoon sun that’s made even warmer and brighter by the radiative heat and light reflected off of the siding. In the summer, we put in plants that can handle the intense heat and light of the afternoon sun: sunflowers, zinnias, garden huckleberries, eggplants, corn, horseradish, and others.

However, in the fall and winter, the earth’s tilt means morning sun gets to this spot a little earlier and the extra heat helps keep these garden beds 5-10 degrees warmer than other spots on a sunny day. We also use low tunnels during the cold months on this side of the house to bump up the temperatures even further for our cold weather crops.

The garden bed on the west-facing side of our house in the summer. Loaded with heat and sun-loving plants like zinnias (to attract and feed pollinators like this Monarch butterfly) and edible plants too.

The same west-facing garden bed in the winter.

Microclimate: East-Facing House Wall

Need a spot to put plants that like morning sun and afternoon shade?

Put them next to your east-facing wall. For folks living in the south, this might allow you to plant rhubarb or other plants that would not typically be able to tolerate the heat. Heat-sensitive salad greens that would wilt in the afternoon sun will also grow well here in the spring/summer.

Microclimate: North-Facing House Wall

Due to a forest and large hill behind our home that blocks the late afternoon sun, the garden areas next to our north-facing house wall only get 4-5 hours of direct sun in the summer and two in the winter. Less sun also means more moisture as well (less evaporation).

What edible plants can be grown in part to full-sun spots? We’ve created a comprehensive list of edible shade plants here.

Microclimate: Low Spots

Need a spot for a plant that likes “wet feet,” e.g. moist soil? Find your low spots. Celery, celeriac, Alexander, parsley, chickweed, elderberry – all love lots of moisture and grow well during the cool months of spring and fall.

Microclimate: Slopes

Slopes tend to have poorer soil and lower soil moisture since water and nutrients run off downhill, rather than staying put (unless you have plants to stop the flow or you construct swales or terraces).

Slopes can be either hotter or colder, depending on which direction they face relative to the sun. Generally speaking, deep-rooted plants and/or perennials are best for slopes since their roots can run deep to mine nutrition, stabilize the landscape, and avoid toppling over during heavy rains. Chicory, comfrey, fruit & nut trees – all can perform multiple functions on a slope.

If you want to see one of the most dramatic and amazing transformations of a heavily degraded, sloped landscape, check out this 13 minute video showing how permaculture design transformed 8.6 million sloped acres in China’s Loess Plateau region.

When we moved into our home, there was a steep slope in our backyard with poor compacted soil that was covered in poison ivy and kudzu. To prevent water and nutrient runoff, we built dry-stacked stone walls made from discarded rocks from a nearby housing development. As a north-facing slope, this is one of the coldest spots in our yard. During the cold months, we grow loads of edible plants under low tunnels on the flat areas. What are microclimates by GrowJourney — When we moved into our home, there was a steep slope in our backyard with poor compacted soil that was covered in poison ivy and kudzu. To prevent water and nutrient runoff, we built dry-stacked stone walls made from discarded native rocks from a nearby housing development. As a north-facing slope, this is one of the coldest spots in our yard. During the cold months, we grow loads of edible plants under low tunnels on the now horizontal growing areas.

Microclimates: Creeks, Boggy Spots, Ponds

It goes without saying that these microclimates are much wetter than other spots might be in your yard/property, and often a bit cooler as well. But that certainly doesn’t mean you can’t grow edible plants in them.

A couple of examples:

True wasabi grows well in water or wet spots with afternoon shade; the less expensive “wasabi” you get at most Japanese restaurants is made from dyed horseradish, not actual wasabi.
Cattails offer a wide array of delicious edible parts. (Interesting fact: cattails can produce more edible starch per acre than any other plant!)
Water lilies and lotuses both produce edible leaves, flowers, seeds, and rhizomes – the rhizomes are considered a gourmet delicacy and often featured in Asian cuisine.

There are far too many other edible water plants to list here. Do keep in mind that many waterways are often polluted with contaminants and runoff that you don’t want on your dinner plate, so eating plants that grow there might not be advised.

Next steps in identifying and planting your microclimates

What to do next now that you know about microclimates?

1. Observe

As permaculture advocates, we’re big on the principle of Observing and Interacting with the areas you’re going to be growing food in. (Here are the 12 basic permaculture principles if you’re interested.)

2. Map & Note

During observation, we’d suggest taking out a sheet of paper to start mapping your property. Make sure to put in your cardinal directions (north, south, east, west). Then walk your property making notes on your map…

Which planting areas are facing towards the sun? Which are on a slope? In a low area?

If you need some help getting oriented, pretty much every smart phone has a compass on it. You can also use mobile apps like Sun Seeker or SunSurveyor to see how much direct sun a certain spot will get at a specific time/date of the year.

If you live in an area that gets snow, a great low tech way to tell what spots in your yard are warmer and colder is to observe where the snow melts first to last. (Eliza, GrowJourney’s Education Director, has a great article on her blog about this.)

3. Create a plant list

Once you have a good idea of your microclimates, you can create a list of edible plants you’d like to try in each spot at different times of the year.

4. Get started now

Experimentation is the goal; trial and error are the expectation.

Let us hammer that point home: mistakes are learning opportunities. The more you try, the more you’ll learn. And over time, you’ll learn how to expertly use your microclimates to yield amazing edible results throughout your garden or edible landscape.

Happy gardening!