All-Season Container Gardening

Gardening in containers is an easy, versatile and creative way to design with plants. Container gardens can be as simple as a scented geranium growing in a terracotta pot, as elegant as a formal planter with a clipped, rosemary topiary or as whimsical as a wheelbarrow loaded with colourful annuals.

No space is too small for containers, from doorsteps to decks, patios and balconies. In the garden, containers can add a splash of colour to bare spots and shady corners. Collections of potted plants can also be arranged on stairways, tiered, ornamental plant stands or to form a "potscape" anywhere you need a focal point.

Season by season, you can use container gardens to welcome spring with pots brimming with bright flower bulbs, embrace summer with window boxes full of cascading annuals, celebrate the harvest with a basket of cabbages and kales and add holiday cheer with an urn full of evergreen boughs. Here's what you need to know to get started.

Choose a Container
Containers are available in a wide range of sizes, shapes and materials. Terracotta provides a near-natural growing environment that's porous enough to allow roots to breathe, and it absorbs excess water. However, terracotta pots need frequent watering and most are not frost-resistant, making them a poor choice for winter arrangements. Many of the modern synthetic materials, including fibreglass or resin, are attractive, weather-resistant and lightweight. These are important factors for balcony or rooftop gardening and for winter containers. Whichever your choice, larger pots need less frequent watering than smaller ones, which dry out quickly. Containers should also have at least one hole in the bottom to allow water to drain freely.

Get the Right Soil
Earth dug from the garden is too heavy for container gardening and can cause compaction, which prevents roots from absorbing nutrients and moisture. Instead, use one of the many specially formulated potting soils, readily available from The Home Depot garden centres. These lightweight mixes are often supplemented with slow-release fertilizers that feed your plants through the season, as well as water-retentive crystals or coir to help retain moisture between waterings.

Plant It Up
Whether you select a combination of annuals, perennials, bulbs or tropicals, choose a colour scheme, a variety of leaf textures and sizes as well as different forms, from upright plants that add height to your design to cascading vines and trailers that soften the edges. Before planting, water individual plants well. Then, arrange them in a container two-thirds full of potting soil, gently teasing out the roots of any plants that have encircled the inside of their pots. Top-up the soil to within three centimetres of the rim and water deeply.

Water Wisely
Throughout the season, check moisture by poking your thumb into the soil to gauge its dryness. This is especially important during hot days and later in the season as roots grow and absorb more moisture. Irrigate as often as necessary and until the water flows freely from the drainage holes.

Fertilize for Flowers
To keep your container blooming, scratch in a time-release fertilizer, such as Miracle-Gro Shake 'n Feed Slow Release Plant Food for Containers, onto the surface of potting soils that are without nutritional supplements. Later in the season, fertilize weekly with a 20-20-20 water-soluble plant food applied at half the recommended strength. Never fertilize when the soil is dry as this can damage roots

Weatherproofing
Not all plants can withstand the winters in most parts of the country. If grown in very large containers, some hardy perennials and shrubs may be overwintered in their pots in a cool garage or shed where temperatures remain just above freezing. Water sparingly until spring arrives.

For winter containers, choose evergreen boughs and ornamental twigs and branches and arrange them in wrought iron urns or winterized resin or fibreglass planters.