When beginning to grow food in a small urban space, you are likely to follow up selecting your varieties with choosing containers. If you are new to gardening, containers help set an achievable goal for your first successful seasons. Likewise, if you are new to an area or need to be wary of ground contaminants containers allow you to grow food crops safely while learning what works and how to heal the ground soil.
Many factors will play into your container selection, but the big ones are function, price, environmental impact, and appearance.
Function
This is the most important factor to consider. The containers you choose should work well for your space, climate, and plant varieties or you will be facing a very long and unnecessarily difficult season.
If you are working with a small space such as a sunny window, narrow and long containers, possibly tiered, will make the maximum use of your space. Small reused cans are good for growing herbs you want to keep separate or to start seedlings, but a lot of valuable space is wasted between each container. When growing on shelves or rooftops, the weight of the container when full of moist soil must also be taken into account. A container dolly on wheels make moving the pots around much easier, but many balconies and railings have a weight limit. If you rent, be sure to check with your building supervisor about load-capacity before selecting your pots and hauling in soil.
Climate should play as large of a role in container selection as it does in selecting plant varieties. Varying materials respond differently to climate factors like sunlight, moisture, wind, and frost. For the tropics, untreated wood will often last only one season and porous clay will dry out quickly in sunny or windy locations. Cement is also a good insulator and becomes very hot. However, when these are the most abundant and affordable materials for your garden, they might seem worth the little extra preparation you can do to make them work for your space.
You must also consider the type of plant you will be growing in each container. Taller plants become top-heavy and require containers with heavier or wider bases. Understanding the root structure of your crops is also helpful. While many varieties are successfully grown in containers that limit their root space (such as fruit trees) doing a little research on their natural rooting tendencies will help you to select the most appropriate pot.
For example, crops with shallow, widespread root systems like cucumber will grow well in shallower containers while corn and tomatoes, with much deeper roots, will enjoy much deeper pots.
However, the best practice is to grow as many varieties together as you reasonably can. If you have space for one large pot which is approximately 1 meter in diameter at the top and slightly narrower at the bottom, you can grow several varieties on a limited footprint. If you raise the height of this container with a tower structure, you increase surface area and can grow even more.
Below you can see how different plants make use of different root zones, allowing them to grow side-by-side in complimentary functions. Above and below ground they fill a different niche, some providing leaf shade and others providing root shade. Will a casual study of these behaviors you can begin to make groupings, or guilds, that make food production more abundant and easier for you.
We will look at creating guilds in more depth later in the series when we discuss planning your plantings.
Price
The cost of getting started, especially when you need containers for your space, can be off-putting for many. If you have the resources, invest in the best materials you can to last for many growing seasons. However, getting started need not be expensive, and often the least expensive options are the most sustainable.
Everyone can start out with free containers. Almost any empty vessel around your home or found abandoned can be used for planting. Coffee tins, milk jugs, cracked buckets – even old shoes – have been used for years. A quick look at online craft and do-it-yourself boards will help if you need some inspiration to re-work different containers to suit the aesthetics of your home. The key points here are to make sure you add sufficient drainage to the container, make clear containers opaque to prevent algae growth, and thoroughly clean all containers to prevent harmful mold and bacterial growth.
Environmental Impact
One of the reasons you are likely to be creating your own garden space is to lessen your negative impact on the environment. Let’s keep this in mind when we start choosing containers.
Though price is often the dominating factor in selecting plastic or synthetic containers, they can leach harmful chemicals and gases, and will not decompose once they are no longer of use as a planter. When we consider that such waste makes up about 14 million tons of America’s waste annually, we can imagine the horrific pile of plastic an individual might leave behind in a lifetime of conventional use. However, this also means a ton (or several tons) of plastic is available for reuse in the garden.
If you choose to buy plastic garden containers, look for heavy plastics with a UV rating or paint them to reduce sun degradation and help them last longer. If you are salvaging, avoid containers that once held harmful chemicals and substances. Plastic is porous and, though it might appear clean, it can continue to leach chemicals into your soil.
Metal is a slightly better option, but again be sure salvaged metal containers were not carrying pollutants and that treated metals will not leach new chemicals into your soil. Most galvanized tin is safe for use, especially if you maintain a more neutral soil pH, but keep in mind its lack of insulation if you decide to use metal containers in very sunny locations. They will get hot. Also, in the humid tropics even galvanized containers will eventually rust out if not maintained. Keep the extra work in mind and the environmental impact of any treatments you might have to use over time.
My favorite choices have always been the most natural – wood and clay. Scrap wood is readily available in trash heaps and timber unsuitable for woodworking is cheap. Even simple logs are a good foundation for a raised bed (a container of sorts). However, the humid tropics are hard on wood. As mentioned before, they usually only last a year with the monsoon finishing them off. But if you have a reliable supply source you will be doing a great favor by keeping the wood out of landfills while building soil as it breaks down. Don’t waste your money buying wooden containers unless you will be growing shade plants under a covered verandah.
Clay pots have been the easiest for me to find here in the tropics. They are made locally from common clay found in the craftsman’s own garden and are often available for purchase at reasonable prices just at the city limits. Old clay cooking pots (common in South Asia) are also a great option for smaller plants. While they will never truly breakdown into soil again, the shards of a broken pot are harmless and will eventually weather as a rock would. These containers are unglazed, though, so still very porous and prone to drying soil. Like every other material discussed, these pots will need some prep work. A light coat of non-toxic clear acrylic will seal the deal, but this is technically a thin coat of plastic which means it is not 100% natural. If you have access to a bentonite clay application for your terracotta pots (check anywhere with pond supplies), you can put together the most natural and long-lasting solution.
Glazed pots are also a safe choice and come free of little maintenance. The colorful designs make building a beautiful garden easy, but they come at a premium. These pots are also more delicate, so do not use them where you will need to move your containers around.
Just make the best choice you can.
Appearance
The appearance of container gardens is technically the least important consideration when it comes to producing healthy vegetables, but it is an important concern for gardening in urban environments. We live very close to one another and our efforts are seen by many. If it looks good, you will enjoy spending more time in the garden and others will be attracted to learn more. Home Owner’s Associations and city ordinances can also be problematic, but if your neighbors like what they see and interact with you more often because of it, you are on your way to forming a support group capable of igniting changes in local laws prohibiting urban gardening efforts.
Come back next week for more on planning your plantings.
