With the increasing popularity of the modern environmental and survival movements, as well as continually increasing food prices, urban gardening has seen a related rise in interest. About half of the world’s human inhabitants now live in cities, and people are starting to realize just how screwed they would be if their supply lines for food were ever to be severed. Having a garden offers an alternative should the S ever really hit the F.
An epic rooftop garden, or “green roof system”, in Singapore. Photo by Henry Leong.
WHY BUILD A GARDEN?
Besides being a lifeline to food in a disaster, there are a ton of other benefits to having your own garden in the city. A good garden should save you money in the long run, as you’ll have to pay less for food. The food is fresher (no more 3 week old salads that have traveled half way across the world!), and safer (no more country-wide e coli scares!) than regular store-bought food.
A mass movement of city dwellers creating their own gardens would lead to a less polluted world, both because plants naturally take carbon dioxide and pollutants out of the air, and because growing your own food means less needs to be shipped across large distances.
A garden will make your home look nicer, as well as give you an enjoyable hobby that helps you reconnect with the earth. It’s a win all around.
THE BASICS- WHAT YOU’LL NEED FOR A SUCCESSFUL GARDEN
Gardening is relatively simple in terms of what is needed. Your 4 most important inputs are: sunlight, air, water and a nutrient-rich soil.
You’ll need an outdoor space that receives sunlight, although how much sunlight you’ll need depends on what you plan to grow. Some areas will have direct sunlight for most of the day, while other areas may have only a few hours of filtered sunlight per day. Different crops would be appropriate for each area.
Next, you’ll need an area with decent air circulation, for your plants to breath. Remember that plants inhale Carbon Dioxide and exhale Oxygen, offering a beneficial symbiotic relationship with humans.
You’ll also need a water supply, but this can be flexible- if a crop needs more water than naturally falls in the form of rain, you can supplement it through watering.
Last, you’ll need a healthy, balanced soil. Soil in the city may be high in lead or other toxins, so you may need to test it first. Even if your soil is decent, you’ll need to supplement it through compost, manure or fertilizer, to supply it with nutrients that it is naturally lacking, or to replace nutrients that have been used up by the plants you are growing.
A good fertilizer will supply nitrogen, phosphorous and potassium in a good ratio. You’ll also want to supplement calcium and magnesium (a dolomitic limestone supplement will supply these both). Having a home compost is a good way to cheaply supply most of your fertilizer needs. For more information, read these articles on improving soil quality and compost 101.
After getting a garden up and running, you will need to consistently maintain it. You will need to remove weeds regularly, and water and prune as needed. So let’s add dedication and persistence to the list.
BACKYARD GARDENS
If you have a backyard, this should usually be your first choice in where to have your garden. It actually has soil (!), and will likely receive more direct sunlight than other areas. It’s definitely the low hanging fruit (confusing pun always intended) of places to support a garden.
The backyard is an ideal place to grow a vegetable garden.
Here are some lists to help you in choosing which plants to grow in which areas. These guidelines will apply to backyard gardens as well as balcony and rooftop gardens.
1) Plants that are easy for beginners to grow:
Carrots, Strawberries, Zucchini, Garlic, Rosemary, Various peppers, Beets, Herbs (parsley, Basil, Oregano, chives, dill, etc)
2) Plants that will grow in shade (4 hrs or less of direct sunlight, some filtered):
Salad greens (leaf lettuce, arugula, etc), Leafy greens (spinach, Kale,etc), Broccoli, Cauliflower, Beans, Beets, Brussels Sprouts, Peas, Radishes
In contrast, fruiting plants will need lots of direct sunlight.
3) Hot weather crops:
Tomatoes, Peppers (hot, sweet), Squash, Egg plants
POTTED GARDENS (FOR BALCONIES AND ROOFTOPS)
If you don’t have a backyard available, you can still build a potted plant garden. This is the option for balconies and simple rooftop gardens.
The same principles above apply in regards to sunlight, air, water and a nutrient rich soil. The difference here is that instead of your plants being planted in the ground, they are planted in soil contained in pots. This gives you the option of moving your plants throughout the day/year and these kinds of gardens are the easiest to make and maintain, but make sure your pots have enough room for the roots to expand.
Some other questions to consider: What plants thrive in your climate? The ones that do will be easier to grow, the ones that don’t will be more trouble and require more maintenance to succeed. Do you want to attract (or avoid) birds, butterflies or bees? Do you receive a lot of snow (which may crack your pottery) or rain (which may drown your plants)? And, most importantly, what kind of fruits or vegetables would you actually like to eat?
Some examples of balcony gardens
Maximizing Space
One of the biggest issues with urban gardens is space. In cities people are often crammed together with minimal personal space, so maximizing your yield with the space you do have is essential. Here are 3 ways to do that:
1) Grow up!: No, I’m not saying you need to become more mature. I’m saying if space is an issue, then do what city planners do- grow upwards. Create multi-level gardens. A shelf with smaller plants on the bottom and larger ones on top can double your yield while taking the same amount of ground space. Garden shelves are available for sale, but milk crates and wooden planks works just fine as well.
2) Start growing indoors and cycle your plants: With some plants, it is recommended to start the plants indoors for the first few weeks. We can use this to our advantage- if there’s a 5 week indoor period, plant the seeds 5 weeks before spring arrives and it’s warm enough to grow outside. 5 weeks before they’re fully ripe and ready for picking, start a second round indoors. This will allow us to fully maximize our yield during the growing season.
3) Grow bags: If you have a balcony or roof garden, consider grow bags. Grow bags are bags filled with soil that you can hang over the edge and grow plants in. They are good for leafy lettuces, strawberries, and various kinds of herbs and flowers.
COMPLEX ROOFTOP GARDENS (GREEN ROOF SYSTEMS)
If you have full access to a roof, and are willing to make a long term commitment to your garden, you may want to consider a green roof system. These are roofs designed for gardens, with built in systems for growing plants, irrigation, drainage, etc. Various permaculture methods are used to make the system as closed as possible.
There are a couple secondary benefits to having a rooftop garden that I haven’t talked about yet. The first is the urban heat island effect. Rooftops in the city tend to be dark and made of asphalt. During the summer months, they absorb sunlight and heat. Having a rooftop garden can reduce the temperature of a building by 5-10 F, which will save energy and reduce the amount of money you spend on air conditioning. This increase in heat caused by dark roofs also has a negative effect on ground level smog, so a city with rooftop gardens will be cooler and less polluted, all things being equal.
The second benefit is that a rooftop garden is an extra layer between your roof and the elements. This reduces the wear and tear your roof faces, and will allow it to last for 50% longer or more.
The best (and cheapest) time to install a green roof system is when a roof is being installed or replaced. If this isn’t an option and you’re using an existing roof, you’ll need to inspect it for leaks or damage, and assess how much weight it could hold. In most cities you’ll need to have it inspected by a structural engineer before you can get a permit for a rooftop garden.
Green roof systems come in two forms: extensive and intensive. Extensive systems have a shallow grow area, are lighter and require less maintenance. Intensive systems are more complex with a deeper growing area, and have the potential for more complex plant systems that may require irrigation or pruning.
A green roof system at McGill University in Montreal.
Things to consider when designing a Green Roof System:
Some of the things you must look at when planning your rooftop garden:
1) Assessing your roof: What’s its condition? Is there any damage to it? How much weight can it support (including things like snow and excess water load)? Do you have full access to the roof?
2) Assessing your future garden: How much would it weight? Remember to include all plants, containers, water storage equipment, heating/cooling/ventilation equipment, etc. Is this in alignment with your roof assessment? How much will it cost? Is this within your budget?
3) Permits: Determine what you need to do to attain all the necessary permits for building a green roof system.
4) Design: A green roof system will typically need an insulation layer above the roof, then a water proof layer, than a root-proof layer. This is usually followed by a drainage layer, then finally a growing layer (covered by a wind blanket in the early days). How will all these parts fit together? How will maintenance be possible?
5) Irrigation: will you plants need extra water? If so, what it the best way to deliver it? Will you need an irrigation system?
6) Drainage: While a rooftop garden will absorb a lot of water, it will still be necessary to have form of drainage system. Stagnant water can add a lot of extra weight to your rooftop and may be harmful to your plants. This can usually be connected to the rooftop’s existing drainage system with minimal effort.
Remember that wind speeds double every 10 stories or so. This can lead to a loss in moisture and top soil, so you need to plan for this.
Good luck and stay prepared!
