Before the pandemic, our garden center organized some courses, and since I’m an old-time gardener, I decided to attend, just to see what new things I could learn. One particular session sparked interest among the attendees, the one about microclimates and how these microclimates can influence our gardens.
Microclimates and the road to success
The commercial gardener, John Hendry, told us about microclimates and how the gardens he maintains would often follow certain growing and productivity patterns that are influenced by their microclimate. After years of practice, he discovered that even though most of the gardens he was taking care of were within 30 miles of each other, what he grew well in a certain garden, was no guarantee that it could thrive in another.
As we all know, what gardeners can grow in the United States is limited by the USDA hardiness zone they’re gardening in, and this has been a general rule and the conventional wisdom passed on from one generation to another. However, this might not be the whole truth, and another success factor that a lot of gardeners are ignoring is the unique microclimate of their gardens.
John talked about season extenders like row covers and how gardeners should use them to warm up the soil and protect their crops from the elements. However, John also stated that there are many more powerful practices that smart gardeners can use. He put a lot of emphasis on becoming aware of and manipulating the microclimate that governs your garden to be able and improve the yield, but also to be able to successfully grow crops that are hardly feasible in your region.
Identifying your microclimates
To be able to exploit the microclimate in your garden, you will first have to learn what microclimates are. This is not a task to be rushed, and it needs to be done at various points during the year in order to obtain a complete picture of how your garden functions and changes throughout the season.
John told everyone to ask themselves four questions about their gardens:
1. Where is the heat stored in their garden?
If you have experience with gardening, you should know by now that the heat doesn’t disappear when the sun goes down. Certain materials and containers in your garden will absorb heat during the day and release it at night. This phenomenon is known as “thermal mass,” and stone, brick, concrete, and even water are subjected to it.
2. Which areas are exposed?
Tender seedlings will often times not survive strong winds, and other plants may be flattened by the howling wind. Also, the soil dries out quickly, and the plant supports can be easily snapped by strong winds.
In a garden, there may be wind tunnels forming as well, and these areas where the wind is forced between solid objects can have a destructive effect on the plants. The wind speed increases when it’s funneled, and you need to be aware of such spots in your garden.
3. Which areas of their garden receive the most sunlight, and how do these areas change throughout the season?
Shadow cast by trees and structures are short in summer and often beneficial to certain plants but are long in winter. However, there may also be spots in your garden you find unappealing, but these spots can be sun-soaked in winter and covered by shadows in the summer. This is why you need to check the sun exposure in your garden throughout the year to notice what changes and to identify promising growing spots.
4. Where does the water pool when it rains?
In general, the low spots and the areas that have poor drainage or heavy soil hold water for longer, and these spots can be useful during torrid days or if you live in a dry zone. However, if you live in a wetter climate, such spots become plant killers.
John advises observing how your garden functions throughout the year and identifying the spots described in the above answers. Once you manage to identify them, the next step would be to take advantage of them and grow the plants that many will tell you do not thrive in your zone.
John provided two examples to help everyone understand how warmth and thermal mass work in the garden. He told us about two gardens he was taking care of that were near each other.
Both of these gardens had the same chilly winters and cool summers, the soil was composed mostly of clay, had poor drainage, and were surrounded by trees and hedges that would often create wind tunnels.
The gardens had certain areas which received full sun for most of the day, and the annual pruning and soil enrichment treatments were the same since he was the one taking care of these jobs.
Even so, one garden yielded good quantities of apples, pears, and currants while the other barely produced any fruits. After a few years of struggling to understand what was going on, he conducted that the main thing that made the difference was thermal mass.
In the productive garden, there were stone walls completely enclosing it, and soft fruits often grew against these walls and thrived even on the north-facing wall. The heat that the wall was absorbing during the day was released at night, keeping frost at bay, thus protecting the delicate blossoms in spring.
He then decided to transplant some of the soft-fruit bushes in the problematic garden so that the plants would grow against the walls of the house. This move proved efficient, and the yields increased considerably, almost matching the ones from the successful garden.
John told us that another way to minimize frost damage to plants is to remove frost pockets from the garden or at least avoid planting tender plants in those spots. The cold air will sink into dips and hollows in your garden, so if you plan to grow plants in those spots, you will first need to fill them up so that they are at the same ground level. You can even grow the plants on mounds or in raised beds to avoid cold spots.
Since frost pours away downhill, you will need to make sure the cold air can escape, and this means that often times you will need to remove any solid barriers that might impede its progress and cause it to pool in your growing areas.
Another alternative to beat these frost pockets is to also choose plant varieties developed for cold areas. Plant breeders can recommend plant varieties with cold tolerance that can be hardy in your growing zone, and these will make a considerable difference to your chances of success
Strong winds are a gardener’s worst enemy, and they can rip their greenhouses to shreds or rip plants completely. He gave an example of working with a garden sitting at the head of a valley that channels the prevailing wind. In that garden, when the wind was blowing between the house and garage, it would often gain speed and become more powerful right before hitting the greenhouse on the property.
He had no choice but to install windbreakers, and this was not a straightforward situation. He couldn’t build a wall or put up a fence since such solid barriers will only force the wind to divert up and over such barriers. The wind will go up and come crashing down on what’s located behind such barriers.
The most useful solution here would be to install permeable barriers since these barriers will successfully slow down the wind while at the same time allowing it to continue its path. This is why hedges are the preferred windbreakers for many. However, for a faster solution, you can even install windbreakers made from netting securely attached to stout posts to reduce the force of the wind.
If you want to grow hedges as windbreakers, one suggestion would be to grow an edible hedge of fruits or nuts to make sure these new plants are an important part of your productive garden.
If you live in a flat region, you could give gardening in sunken beds a try since this gardening method is often used in flat areas. In general, six inches deep should be more than enough to protect the delicate seedlings. If you need to go much deeper, you will need to create berms. These mounds will deflect the wind and channel it away from your plants.
Also, if you decide to go with this approach, make sure the sunken beds are not located in heavy soils since these will be more prone to waterlogging.
When dealing with windy spots, plant selection also plays an important role in the overall success of your garden. Choosing bush beans instead of pole beans is one such example. Letting the cucumbers, tomatoes, and squashes trail over the ground is another idea. Rather than supporting these plants on fragile trellises and letting them at the mercy of the wind, let them grow freely on the ground.
Also, how about growing narrow-leaved garlic and onions in regions with strong winds? These varieties are more resilient than their broad-leaves cousins.
Working with sun and shade
Shade covering in a garden varies according to the time of the day, the season, and the plant/structures creating the shade. A garden can be shady for most of the afternoon and still grow a wide range of vegetables if it receives morning sun. For example, leafy greens, bush beans, carrots, beets, and celery are all happy with just a few hours of direct morning sunlight.
If you are dealing with shady spots in your garden, you will need to grow plants at a wider spacing to allow them to absorb as much light as possible. This eliminates shades caused by planting too close. A trick to enhance available light would be to install light reflectors in your garden or paint vertical surfaces in light colors so that the light is reflected back onto the plants in your garden.
While most gardeners see shade as a bad thing, they fail to realize that it can also be used to their advantage and grow crops that have a hard time growing in full sun. In fact, shade is a real benefit for the gardens located in hotter climates. For example, lettuce, arugula, and beets are crops that are known to be susceptible to bolting in hot weather, so these should be planted in spots that benefit from the afternoon shade.
After years of gardening, I’ve learned that areas where water drains slowly, are ideal spots for growing thirsty crops in hot summers, helping us to save water and reduce the frequency of watering works. If you want to follow this approach, please keep in mind that such areas will warm up slowly in the spring, so make sure to avoid them for the earliest plantings.
If the soil is persistently wet, it’s best to plant on top of mounds or in raised beds to avoid digging drainage channels and to help lift the plants a few inches above the water table. We often add compost or manure on top of the beds to create mounds. Sometimes we use boards o frame the bed, but this is rather optional for us.
If you are dealing with sandy soil and you want to help improve it to retain moisture, mulching with organic matter is recommended, especially in warmer climates. When gardening on dry soil or slopes, plant in shallow depressions made in the soil so that plants sit lower than the surrounding soil level. When it rains or when you water, these depressions will help water collect around the plant. Water pooling is highly beneficial if you are working with soils that dries to a hard crust, and it will give water enough time to soften the crust and percolate down.
If you live in a dry climate and the hot air creates high rates of evaporation, the best option to make sure the plants get enough water is to use an olla. These earthenware containers are placed into the ground next to plants and filled with water. Their porous nature allows the water to escape into the soil and go straight to the roots.
Gardening is serious business, and every garden should be seen as a long-term project. You need to take time and observe your property and notice how the climate affects it since only then will you be able to discover the limitation of your garden and the possibilities you have for successfully growing food.
If your neighbors are doing a much better job than you and get better yields, the secret may not rely on their knowledge and expertise but rather on their garden’s microclimate and how they learned to work with it.
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