A well thought out garden design can make weather extremes more bearable while shaving heaps off of our greenhouse gas emissions, energy use (and bills!). Lets look at some of the simple things we’ve done at Ligaya…
Conditions that we deal with
Our place gets direct sun from North East to West as the Sun passes over in Summer. Our location means that we get pretty direct sunlight on the longest side of the house, coming straight in from the West until about 6 pm on a Summer evening.
Also, we get hot, dry Northerlies in Summer and cold South Westerlies in winter.
This makes it important for us to control our Western flank. Fortunately, that’s where our garden is located and there is much one can do with garden design to ameliorate climatic extremes. We have more problems with heat than we do with cold, so this page will deal mostly with how we’ve tried to deal with that.
Over time, we’ve found that deciduous trees and other deciduous plants are one of our best tools for improving our immediate climate.
Lets take a deciduous tree, maybe a plum tree. In summer, if placed well, this tree can shade a wall of the house, a window or porch by blocking the direct rays of the sun.
In winter, when the leaves fall, this tree will allow the sun’s warming rays to hit the house, providing free heat.
The structure of the tree can slow breezes, whether hot cold, while the movement of the branches can amplify existing breezes beneficially when fully clothed in leaves.
Trees transpire water. They are like huge pumps that take up water through their roots, transport it through trunk and branches and let it evaporate in a controlled manner through their leaves. This means that our tree can cool the air passing through its canopy, just like a huge evaporative air conditioner!
Our plum tree will also shade the ground around it, meaning that good placement will allow it to prevent the ground near the house from heating up and cool breezes that pass by, before they reach the house.
With this in mind, we’ve placed a line of deciduous fruit trees between us and the west.
Mulch can be greatly beneficial too. It insulates the ground, keeping it warm in winter, cool in summer. It retains moisture, cooling air passing over it in summer and adding welcome humidity (welcome on some days in some areas, that is).
Mulch can also stop sunlight and heat from being reflected by bare ground and onto the house. It really is worth mulching well. We spent a bit on mulch, and are adding to it any way we can.
Gravel can be a beneficial way to cover soil too. We use it in all our paths. Cream gravel helps us to brighten the garden, but it has several more jobs. Our gravel paths are positioned to funnel cool southerly breezes toward the house in summer. The gravel can hold water and let Summer breezes pick it up, cooling the air. The paths are well shaded by trees in summer, letting that air cool even more.
Plants of every type can help cool air, by just the ways we’ve discussed; slowing wind, allowing evaporation, providing shade and preventing heat from being reflected to the house.
Vines are great too. We have a mix of deciduous and evergreen vines, depending on their position around the house. We have a choko and a passionfruit that form the bulk of the growth, shading the house in summer. They also make large pockets of still air between them and the house. On our ENERGY(link) pages you can read how still air is the best insulator. This means that evergreen vines can do a great job with climate control even in winter.
There are also a hops vine and grape vine near the front porch. These lose their leaves in winter, allowing welcome sunlight to hit the living room walls, windows and front door.
Hugging the walls on trellises are jasmine and honeysuckle vines. Once again, they shade the walls and trap air against them.
The southern end of the garden has two Olive trees that, when grown, will reduce the strength of those cold southerlies.
Plants and landscaping can also create their own air movements. Air moves when there is a physical force or a temperature differential in the area.
We can create our own micro air movements by carefully shading and sunning small areas. The cold air will move to the hot and this will create a tiny breeze. Differences in height in the garden can also do the same, as cold air falls. Using raised beds can cause tiny cascades of air as we water the top of them. This type of engineering needs careful planning and is beyond most of us as there are so many variables involved.
Of course, the watering system can be used in many ways to alter the climate in summer.
Watering plants, ground and beds allows evaporative cooling to take place, sprinklest can cool the air directly and micro sprays and misters close to the house can be a blessing by cooling us directly.