Gardening in containers allows people to garden where plants would not naturally grow. This can be anywhere but container gardening is used mostly on patios, balconies, entrances or in areas where other plants dominate.
Like all gardens, container gardens thrive if they have good drainage, water, sunlight, fertile soil, room for roots to expand and a steady supply of nutrients.
There are exquisite containers available, but the container can be any item that holds soil and has holes in the bottom to allow excess moisture to escape.
This being said, containers that hold a small amount of soil tend to need water twice a day or through continuous irrigation to provide enough moisture and nutrients to supply the needs of the plants.
On the Internet, pictures of strawberry plants in eavestroughs, gardens in sewer pipes, and pallet gardens are very common. The plants always look lush and healthy, which is achievable if the plants are spaced far enough apart to let large root masses develop and the plants are given water and nutrients on a regular basis. It is much easier for the average gardener to develop a good garden when plant roots can expand downwards at least eight to 12 inches (20 to 30 cm).
Containers such as large urns or halved whisky barrels are deep and have a large diameter. Filling the container with soil could make it prohibitively heavy. An alternative is to use a light filler such as styrofoam for the bottom of the container and fill the top foot (30 cm) with soil. Plants will survive in less soil but more soil will allow the plants roots to expand, producing a healthier plant. Water absorption and retention improves with deeper soil.
Match the plants in the container with the amount of sunlight that the plant will receive. Plants that thrive in the shade will shrivel and die on the south side of the house.
Annuals, perennials, cacti or vegetables will thrive in containers. Annuals and perennials should be planted close enough together that the plants will quickly overlap, filling the pot. Cacti look best if individual plants are easy to distinguish. Vegetables should be planted far enough apart that their leaves overlap but allow the plant enough room to produce a good crop.
Soil makes the garden not because it is nice to look at but because without good soil, plants will not thrive. A good soil for container gardening will be an equal mix of good top soil, humus, and perlite or vermiculite. The top soil will provide the soil structure and contain nutrients. Humus absorbs moisture and adds to the nutrient supply, with the exception of peatmoss.
Too much organic matter will use all of its own nitrogen to break down the material or burn the root of plants as they germinate, resulting in poor growth of plants.
Vermiculite and or perlite create air pockets within the soil. This insures that the excess moisture will drain from the soil and that the soil will not become hard and compact. Roots have a hard time expanding into the surrounding soil if it is hard. A larger root base means a larger, healthier plant that needs watered less often.
In Central Alberta, containers are expected to last from mid-May until mid-September. To get the most out of the season, fertilize on a regular basis. If the plants have a constant source of nutrients, they will put out consistent growth. For this reason, a small amount of fertilizer can be mixed in the water with each watering.
It is always best to read and follow the instructions on the fertilizer package. Continuous watering with fertilizer will cause salts to build up in the soil but it can be avoided by watering heavily once a month to flush out excess salts. Containers are great as they allow many to garden who do not have the ability to grow a traditional garden. For more information on container gardening, contact the Clearwater County and join their workshop on April 29.
Linda Tomlinson is a horticulturalist who lives near Rocky Mountain House. She can be reached at your_garden@hotmail.com.