What to plant on a rooftop garden?
Not all gardeners have a backyard to grow in. Especially as Australian properties become smaller and more dense. Whether you're in Sydney, Melbourne, Perth or Brisbane it's the same story.
Some of us have limited space, so our desire to garden leads to creativity. Windowsills, porches, and rooftops may be unorthodox, but they can still support a vibrant garden. Rooftop/urban gardening and indoor gardening has been gaining popularity as young gardeners bring their green thumbs to urban living. There are a few obstacles to overcome, but with a few changes and considerations, you can have a beautiful garden growing right above your head.
Bringing gardens to locations usually not considered a “growing space” is innovative and fun. We can satisfy our gardening habits without the traditional backyard and bring life to previously barren locations. Although the challenges are slightly different than those faced by traditional gardens, they can be easily overcome with know-how. If you want to garden, but don’t have access to ground space, then you should consider rooftop/urban gardening with a raised garden bed or container.
To start, you need to be aware of the following factors:
Rooftop/Urban Gardening Factors and Benefits
Along with utilising previously vacant space, rooftop gardening is environmentally friendly in that rooftop gardens help mitigate heat buildup from the sun on buildings. Of course, it also provides produce that doesn’t need to be shipped, thus taking a small but contributory piece out of our carbon footprints). From a practicality standpoint, rooftops almost always provide ample sun exposure for plants.
It’s not a new practice, but it’s becoming a major gardening trend in places that were previously food deserts such as Chicago and Toronto. It’s often socially championed by Millennials, younger gardeners who don’t have traditional gardening areas like a backyard and who are looking at other available options. However, this is hardly a young generation’s trend, as rooftop gardening is meant to be enjoyed by all. Upon the expanding popularity, time and experience has yielded some important growing considerations that can make or break a rooftop garden. Here’s what you should consider when starting your rooftop garden:
Structure Integrity: Roofs may be strong, but they aren’t designed with the intent to support the weight of an expansive garden. Soil and materials are heavy and get heavier with added water. If you want to build a large garden on your roof, speak with a structural engineer first and heed their advice. Fortunately, almost any roof can handle a few lightweight containers filled with soil.
Watering: Due to possible access restrictions or challenges, you’ll want to consider watering options. One of the best methods is to use a ground-level garden irrigation system connected to a nearby water supply. This way you don’t have to transport water to your rooftop garden every time it’s thirsty, and you are maximising your water efficiency (sprinklers and misters are subject to high amounts of evaporation). Because your garden will be more exposed to the sun’s heat, water utilisation is vital. You’ll want to ensure the soil stays moist. If using a ground-level irrigation system, we recommend connecting a timer to it for even more convenience.
Sun Exposure: One of the biggest concerns of growing on a rooftop is the heat. Although gardens love the sun, too much exposure can kill them quickly. When searching for the perfect place to start your urban garden, try to find an area where your plants will get some reprieve from the midday heat. If there is none, maybe a neighbouring building casts a shadow that you can take advantage of. If it is totally vulnerable to the sun from morning till evening, you can always erect a simple cloth shade. Just stick some supports in the soil that can hold up some shading that will protect your garden during part of the day.
Which Plants Are Right for the Rooftop?
Just because your rooftop is a viable growing location doesn’t mean everything will thrive. It can be a harsher environment than what ground-level gardens face, meaning the plants often need to be hardier. You want to choose plants known for their resilience to your rooftop’s extremes (sunlight, heat, and maybe even drought) so they can weather the occasional extremes. Similarly, you’ll want to consider the root structure needs of a plant. In this case we’ll use a common growing medium of an eight-inch deep raised garden bed (filled to the top with soil) during the summer. Plant characteristics we’ll want for a rooftop garden like this would need a root depth of less than eight inches and the ability to stand-up to long bouts of sun and heat. Here are some plants adaptive to that environment:
Peppers – They love full sun and tolerate heat well. Plant ground covering crops like basil with them to help keep soil cooler.
Basil – It loves warmer temperatures and six to eight hours of sun. Planted with taller plants, such as peppers, aides in giving them a reprieve from too much time in the sun.
Okra – A southern native, okra loves warm weather, lots of sun, and is fairly care-free to grow. It offers wind protection to the frailer pepper plants and may also help with concerns of aphids. Keep some growing stakes on hand, though, as okra can grow to be six feet tall.
Plants to avoid, unless you have added shade or deeper rooting availability include greens and large rooting vegetables.
Growing plants on your rooftop takes a bit of planning and research, but one you get it all dialled in and begin to harvest flavourful, healthy produce, you’ll be the envy of your neighbours.