Microclimates are one of the biggest factors affecting our success with growing healthy plants. Every garden is totally unique. We have to play ‘detective’ to discover clues in different zones to fully understand the opportunities and challenges. Let’s dig deeper into what kinds of microclimates might be in your garden and how to use them to your advantage.

Guide to Understanding Microclimates in your Garden

What is a Microclimate?

A microclimate is a suite of very localised conditions that differ from those in the surrounding areas. Often just slightly but sometimes considerably! Think of a microclimate as a miniature climate. It may be less than a metre or few feet in size or a substantially larger area in your garden! Microclimates may occur naturally, or you can intentionally change the conditions to suit your needs.

What Aspects Affect Microclimates in your Garden?

There are a variety of factors that influence microclimates in our gardens. These include:

  • Air and soil temperature. These conditions affect seed germination and plant growth.
  • Solar radiation and sunlight angles during the year affect daylength and shade.
  • Wind speed and direction can provide cooling breezes or hot dry and damaging gusts.
  • Humidity (high vs low).
  • Soil type, moisture-holding capacity, pH, drainage and structural properties.
  • Rainfall and moisture.
  • Vegetation and maturity of established species. A new house block with no plants will have a very different microclimate to when mature shrubs and trees are growing.
  • Directional aspect the garden area faces (N, S, E or W).
  • Slope, elevation and topography (affect temperatures, frosts and water movement). e.g. A low level property in a valley may have lower temperatures as cold air sinks. Gardens may get frost and have more moisture from run-off. Whereas a property on a hill may be cooler and have drier soil.
  • Air circulation (well-ventilated areas are cooler).
  • Thermal properties of building surfaces and nearby structures like walls or fences. For example, most glass reflects some heat but does absorb a small amount and diffuses a lot of direct solar radiation. Bricks and concrete absorb and store heat on warm days and release it overnight creating a warm microclimate in the immediate area. Some hard surfaces like a path, paving or driveway may radiate extra heat.
  • Surrounding buildings in cities and densely populated areas can also be impacted by the urban heat island effect.

Gardens Can Help Mitigate Urban Heat Islands

No Two Garden Microclimates are the Same

These various dynamics can create comfortable, favourable growing conditions or especially challenging ones! It’s worth playing detective to investigate the microclimates in your garden. Not all of those factors may influence the conditions in your garden. But at least some of them will.

I live in a subtropical climate in SE Queensland, Australia. However, even within our local region and suburb, the microclimates are very different. Based on regular feedback from my neighbours who are also keen gardeners, the prevailing winds, rainfall and sunlight exposure varies widely from one side of our street to the other! It can be wildly windy on one side of the street and peacefully calm on the other. We even experience different rainfall depending on which way the wind is blowing! We often compare our data and although we live in the same street just metres apart, our aspect, soils and rainfall vary considerably.

Depending on the aspect your garden faces, you may encounter a wide variety of microclimate conditions. e.g. harsh sunlight or full shade, strong prevailing winds and damaging storms or cooling breezes that bring relief on hot days.

I discovered last year when planting out a newly established terrace garden for the first time that it had poor air flow and high humidity due to windbreaks on two sides. The neighbouring trees cast too much shadow and the zucchini plants quickly succumbed to powdery mildew in these unfavourable conditions. This season I planted them on another terrace in full sun with good ventilation and light breezes. They produced a great crop with far less problems. Lesson learned!

Why Do Microclimates Matter?

Like us, plants have needs! Some plants prefer shade relief, lots of soil moisture or wind protection. They’re a little bit precious! Others are tough. Mediterranean herbs like rosemary and oregano can handle hot dry windy conditions. Whereas thirsty herbs like mint will shrivel up without moist soil. Where you locate each plant is SO important.

Basil chives rosemary & mint herbs on a warm sunny protected window sill indoor microclimate

Basil chives rosemary & mint herbs on a warm sunny protected window sill indoor microclimate

The more familiar we are with the microclimates within our gardens, the better decisions we can make about what to plant where. For example, most vegetables do best in well-drained nutrient-rich soils. However, our overall climate (e.g. tropical, subtropical, temperate, arid) seasonally impacts the growing conditions for our plants. For example, in cool climates, sun-loving cucumbers likely need a full sun position to access maximum heat and sunlight hours. However, in a warm-hot climate, these thirsty vegetables may need at least some partial shade protection to minimise moisture loss and sunburn.

Whilst many edibles can adapt to less-than-ideal growing conditions, you may struggle to grow healthy plants. I aim to match plants to the microclimates that best suit their needs.

Have you ever moved a struggling plant to another location then watched it thrive? Almost like it’s saying “Thanks for moving me – I’m SO much happier here!Changing the microclimate or relocating a plant to more favourable conditions can make a BIG difference. For example, I used to grow ginger in full sun. But after it constantly suffered sunburn and wind exposure that dried it out, I realised it needed shade protection especially over our hot summers. I now grow it in portable pots so I control the microclimate seasonally or under the protected canopy of a tree or shrub.

Observe and Record Your Microclimates

We can work with what we have or improve the microclimate conditions so we can grow the plants we want. Sometimes we may have to compromise or select plant varieties that will thrive rather than just survive! Don’t give up. Observe. Adapt. Experiment.

So, it’s time to put your detective hat on and go hunting for clues around your garden for zones with a unique set of conditions.

Sunny and shady microclimates in a small garden

Sunny and shady protected microclimates in a courtyard garden late afternoon

Microclimates can vary widely even within a small garden. Here are a few examples.

  • A cool shady spot with partial filtered sunlight under a tree canopy.
  • Waterlogged boggy soil suitable for plants that don’t mind wet feet and love moisture.
  • A humid warm greenhouse ideal for raising seedlings or overwintering sensitive plants.
  • A sheltered full sun patio with reflected heat from a brick wall or glass door.
  • A high-rise balcony exposed to strong winds.

I encourage you to take time to discover your different microclimates by being observant. Note down all the different microclimates you can see. This will help you make informed choices about your plant selection and protect your crops.

Download your easy-to-use printable worksheets in the Garden Journal Planner and Workbook to get started.

5 Ways to Create Beneficial Microclimates in your Garden

1. Use plants to create a living windbreak. Filter wind and create a more protected microclimate. Shelterbelts can reduce damage-causing turbulence in an exposed location and slow cold air flow coming downhill. Hedges allow wind to pass through slowly. They create a more favourable growing environment and habitat for wildlife.

2. Create shade with climbers. Grow vining plants that climb up a trellis, arbour or other vertical structure. Climbing plant foliage can help shade your garden. Trellises are particularly useful for mitigating wind and filtering sunlight. Peas, beans, passionfruit, nasturtiums, cucumbers, grapes, kiwi fruit and berries are edible climbers. Many climbing flowering ornamental species also create shade and mitigate wind.

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3. Utilise cloches. Use an individual cloche to protect young seedlings from drying out or from frost.  A greenhouse, larger frames with glass or clear covers are ideal to create a warm microclimate allowing sunlight in. Warmth and humidity with air flow are ideal microclimate conditions for propagation. However, during summer, vulnerable seedlings could be sunburned or suffer heat stress. So, timing planting activities in harmony with the seasonal conditions is important!

Shade cloth helps create a protected shady microclimate during hot weather

Shade cloth creates a protected shady microclimate during hot weather to prevent lettuce bolting to seed

4. Shade cloth. In hot, dry and windy conditions, shade cloth material can be life-saving for your plants. I use shade cloth from spring through summer to minimise damage from wind and heat. It’s also ideal to protect against hail or wind damage during storm season. Shade covers reduce the ambient temperature in the soil and around the plants. By lowering direct solar radiation, plants lose less moisture and avoid heat stress symptoms. Shade cloth is a water saving strategy too.

The Benefits of Using Shade Cloth on Yield and Quality of Vegetable Harvests

Click to read from Page 38: The Benefits of Using Shade Cloth on Yield and Quality of Vegetable Harvests

5. Use shade to water less often. Plants grown in partial or full shade usually don’t need as much water as those in full direct sun. There are many edibles that are shade tolerant. Group plants with similar moisture needs together to minimise watering in a shady microclimate.

I hope this guide has helped you learn more about microclimates and provided practical strategies to create beneficial growing conditions in your unique garden.

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