If your rural home is built on rock, or you live in a condo, you can still enjoy many the benefits of gardening by planting flowers, herbs and vegetables in containers.
by Ben & Mark Cullen | photography by Mark Cullen
Container growing is often the only way to grow fresh veggies and bold flowers with the balcony, patio, porch or pool deck providing the platform.
It is not always easy though; a container is not the natural home for any plant and, as such, you may find yourself struggling with the right sized container, the best medium for the job, plant arrangements, or placement.
A Canadian winter can be tough on containers. Regular clay pots do not stand up well to freezing temperatures and you may come back in the spring to a cracked, or completely split, pot. This is avoidable though.
If you prefer clay pots, ask for one that is double fired. It is much stronger and able to withstand the changing temperatures. Most plastic containers withstand the weather changes but if you are unsure, it’s best to pack them away where the snow and ice can’t reach them. The key to preserving your pots from one season to another is to either avoid freezing, or empty your pots in the autumn, clean them and turn them upside down in a dry place like your garage or tool shed.
You should know where the container will be located before you choose the size – there is nothing worse than getting it home and realizing it is too big to fit in the space. Then decide what you will be planting in it.
Herbs grow well in dry conditions, so a deep container is not essential. We prefer to plant ours in elongated rectangular-shaped containers. Growing a tomato? They are heavy feeders with an aggressive root system, so choose a container that has a volume at least equal to the size of a bushel. If space is limited, grow your tomatoes in an upside-down hanging tomato planter.
The demands of annual flowers and perennials vary a great deal. Some enjoy – or tolerate – dry conditions while others need to be watered regularly. An astilbe, for instance, is unforgiving when allowed to dry out. The wilted foliage is not particularly good at rehydrating, but a geranium is.
Always use a container mix as garden soil is heavy. It has far fewer pores than a potting mix and will become compacted with watering, further decreasing porosity making it difficult for shoots to pop out of the soil and roots to delve deeper.
The best soil is no soil at all. That is, a soilless mix. These mixes are created to be used in pots and contain large amounts of peat moss and compost to help retain moisture and nutrients while allowing for good oxygen flow.
For heavy feeding plants, like tomatoes, your best bet is a vegetable and flower mix which provides extra nutrients to promote healthy growth.
Know the sun exposure – or shade – of the location. That is, north-, east-, south-, or west-facing. Each direction will provide the area with different amounts and intensity of light. Exposure to wind is a consideration when choosing plants for containers, also.
Choose plants accordingly and keep this list on hand when you do your shopping:
Shady, windy side of the house
This is the best area for annuals: tuberous and fibrous begonias, coleus, trailing lobelia, and browallia. Impatiens have been used for years but are susceptible to a form of downy mildew that can wreak havoc with them later in the season.
Perennials that perform well in a container located in shade include heuchera, hosta, tiarella, ferns and lily of the valley.
This direction will provide about six hours of sun during the morning while sheltering them from the hot afternoon sun and the north/west wind.
This is an excellent place for geraniums, petunias, dusty miller, double impatiens, lobelia, snapdragons, tuberous begonias, and salvia. Perennials that perform well in half a day of sun include all of the aforementioned “shade” plants plus monarda, daylilies, oriental lilies and shasta daisies.
Bright and hot
These containers will need plenty of water and it is best to plant tough, heat-seeking annuals here. Best choices for a south-facing container include portulaca, zinnias, cleome, marigolds, four o’clock, geraniums, bacopa and bidens.
Perennials planted in a south facing pot need to be very drought tolerant, generally. Look for Echinacea, hens and chicks, mint and all of the Mediterranean herbs.
Hotter and drier
Hotter and drier than southern exposure due to the wind. Only the most sun-loving plants will thrive here where the sun hits during its maximum afternoon intensity.
Best choices for this kind of exposure include portulaca, zinnias, marigolds, hanging or balcony-type geraniums, dusty miller, salvia, snapdragons, cleome and petunias. Keep an eye on the water situation as the high heat and wind is likely to dry out everything a little quicker than you would expect.
Perennials that will perform well here include all the sempervivums (hens and chicks), yarrow and roses, providing the container is large enough to accommodate the roots.
Assess your area carefully: nearby buildings and trees can cast shadows that effect plant growth. If you have a large tree that provides excess shade, choose more shade tolerant species.
Making Colourful Displays
At one time, mixing annuals, herbs and perennials in the same container was taboo. Now it is commonplace and really makes it easy for all-season colour. Some of our favourite combinations include:
Sun: Perennial Guara/Indian Feather with annual sweet potato vine. Perennial Scabiosa Butterfly Blue, perennial creeping Jenny, with annual geraniums and/or cape daisies
Shade: Perennial hosta with begonias and dusty miller. Most any kind of fern with coleus and viola.
Herbs: These indispensable kitchen flavours are, for the most part, best grown in full sun. Be sure to check the labels when you buy them to be sure. Provide herbs with at least five hours of direct sunlight and avoid fertilizers which only promote long, stringy growth.
Above all, remember to match each plant to its appropriate place and to relax and have fun with the experience.
Mark Cullen is a Member of the Order of Canada. He reaches over two million Canadians with his gardening/environment messages every week. Receive his free monthly newsletter at markcullen.com. Ben Cullen is a professional gardener with a keen interest in food gardening and the environment. He is the owner of Cullen’s Foods (cullensfoods.com).
You can follow both Mark and Ben on Twitter: @MarkCullen4, Facebook: MarkCullenGardening and Instagram @MarkCullenGardening