By: Raffaele Di Lallo, Author and founder of Ohio Tropics houseplant care blog
Understanding indoor microclimates is a very important stepin houseplant care. What is a houseplant microclimate? This is simply an areawith various zones in our homes that have different conditions such as light,temperature, humidity and even air circulation.
Some of us may have heard of microclimatesoutdoors, but you may be wondering are there microclimates indoors too? Theanswer is YES, so let’s discuss what this means and why it is important.
When you decide where to place a certain plant, it isimportant that you give it the best location in your home.
Various locations of your home can have drasticallydifferent humidity levels in the air. If you have plants that like higherhumidity, such as fernsor calathea,it is important to try and increasehumidity. You can create a humid microclimate simply by grouping manyplants together. Plants will naturally transpire water and create a more humidmicroclimate for themselves.
Other options to increase humidity are locate your plants innaturally humid areas such as bathrooms (assuming, of course, that yourbathroom has enough light for your plants!) or the kitchen. You can also use ahumidifier or set plants on top of humiditytrays filled with pebbles and water. The water level should be below thepebbles and, as the water evaporate, it will create a humid microclimate.
Light can vary greatly throughout your home. It is notenough to say that you should place a certain plant in front of a northernexposure window, for example. Not all windows are created equal. The size ofthe window, season of the year, obstructions in front of a window, and otherfactors can vary the amount of light substantially. Use a light meter to get anidea of which locations are darker or brighter.
Many of us set thermostats throughout the year, whether itis for air conditioning or heating. Does this mean that the entire home will bethe same temperature? Absolutely not! Hot air rises, so the second floor ofyour home may be warmer. Situating your plants next to a heating vent may alsoresult in a microclimate of both higher temperatures than you’d think, as wellas drier air.
One good way to study the temperature in variousmicroclimates in your home is to purchase a minimum/maximum thermometer. Thiswill tell you the lowest and highest temperature in an area within a 24-hour period.The varying results throughout your home may surprise you.
Last but not least is air circulation. Many people don’teven consider this microclimate factor. It can be extremely important for manyplants, such as epiphytes(orchids,bromeliads,etc.) that are used to high air circulation. Simply turning on a ceiling fan tocirculate the air can help provide better growth conditions for plants, as wellas help deter fungal diseases that can flourish in stagnant air.
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Garden beds warmed by reflected heat
A microclimate is a small area with slightly different temperature or climate than the surrounding larger area. Every garden has microclimates microclimates can be created by hills and low spots, structures and fences, and even the shade of trees or tall plants.
You can use the microclimates in your garden to help vegetables produce a little bit better—a little faster, a little bigger, even a little tastier.
Map the microclimates in your garden by noting where the sun shines most, where shadows fall and when and where breezes blow and where they don’t. Look for natural low and high spots that may stay cooler or warmer than the surrounding area. In the cool time of the year, note where patches of snow and frost disappear first and where they linger.
Take into consideration surrounding structures—a house, a shed, fences, or walls. Wood and stone structures absorb the sun’s heat during the day and release it back into the garden at night. Gardens on the south and west side of structures get the most sun each day and will warm more quickly. An east-facing garden will get the first sun each day, but can be in shadows by afternoon. North facing gardens get the least sun and stay cooler year round. North-facing slopes are cooler than south-facing slopes which also will be drier.
Cold air moves to the lowest spot in a garden—expect cool temperatures and frost to linger in low spots. A fence without an opening at the bottom of a slope can trap cold air.
Wind and breezes will increase heat loss in a garden. Winds can stress plants and slow down their development too much wind can dessicate plants. Look for natural windbreaks when planning a garden—trees and trees lines, large shrubs and hedges that keep winds from reaching vegetable planting beds and drying them out. Consider planting natural windbreaks when planning your garden.
Locate your vegetable garden where it is not shaded by buildings or trees. Place the garden at least 20 feet away from tall trees that will cast shadows and compete for water and nutrients.
Avoid low spots that are slow to dry in the spring. Cold air will collect in these spots.
On slight slopes run rows at right angles to the slope so that each crop gets maximum sun exposure. Where slopes are steep let rows follow the contour or terrace the garden.
Crops that thrive on heat such as tomatoes, peppers, eggplants, and beans should be planted in south-facing or west-facing gardens or in rows that run north and south. Heat-loving crops can be planted close to walls and fences that absorb heat during the day and reflect it back into the garden at night.
Use stone, brick, and gravel pathways to capture the sun’s heat during the day and release it slowly into the garden at night. Stone and gravel paths can surround mounded or raised beds for crops that demand warmth and heat.
Create a thermal mass for crops to change the microclimate and aid plant growth gallon milk containers filled with water can soak up the sun’s warmth in the day and keep plants warm at night.
Where gardens are exposed to breezes and winds, create natural windbreaks by planting dense trees such as conifers or create seasonal windbreaks by planting sunchokes, sunflowers, or corn on the windward side of the garden. If planting is not an option, create windbreaks for individual plants by propping up shingles, sheets of plastic, or staking bottomless sacks around plants.
Use cooler and warmer spots in the garden to your advantage. Cool and shady areas can be planted with salad greens and root crops during the summer. Interplant crops averse to too much sun or heat in the shadows of taller crops.
Attach shade cloth or lattice to hoops or frames above crops that want cooler temperatures during the summer. Plant leafy crops in east-facing gardens during the summer they will be shaded in the warmest part of the day.
Review your garden’s microclimate map each season to see if there have been changes.
LTK: Has Global Warming had an Effect on these Zones?
LW: There have been some regional changes made in some areas as a result of global warming, but I don't think they are definitive. The National Arbor Day Foundation has shifted some zones farther north, but this has been controversial.
LTK: How Strict are Planting Zones?
LW: They are only a guideline, but they are very useful. Local microclimates will also influence what you can grow. Slope of the land, elevation, large bodies of water, exposure and proximity of buildings, etc. can make areas warmer or cooler than the overall climate region.
LTK: How can Planting Zones be Extended?
LW: By choosing microclimates wisely or by providing winter protection, but its not something I recommend for beginners.
LTK: Is it Possible to Garden in Extreme Zones?
LW: Of course, there are plants that can be grown almost anywhere. Native plants are always the best choice for severe climates.