If you’re planning a container garden, you’ll want to choose the perfect pot to enhance your plants and add to the beauty of their place in your garden. First you need to decide on the type of material to use — wood, terra cotta, ceramic, clay or metal. Do you want something whimsical such as an old sink, wheelbarrow or milk can, or something more formal such as a classic urn on a pedestal? You should also consider whether the material you select suits the location for your plant and its container. A formal brick patio, for example, is perfect for terra cotta pots or cut stone, while a rustic deck is just the place to use a planter box made from recycled wood.
Whatever you choose—whether you buy containers, make them yourself, or improvise, the materials, colours and shapes will make a statement about your personal taste. Approach the selection process from a practical, horticultural point-of-view, evaluating whether the containers will be good for the plant. If they’re the right size, material and shape, they will only add to the plant’s overall health and beauty.
Think About Porosity and Drainage
Keep in mind two key factors in your choice of garden containers: porosity and drainage.
Porosity: Typically, porous containers breathe to some degree, although it isn’t a major factor in water evaporation from the soil since most water loss is through the leaves and evaporation from the top of the pot. Unglazed terra-cotta, wood and paper pulp may dry out faster but they also draw away excess water and prevent waterlogged soil.
Non-porous materials like glazed terra-cotta, plastic and metal hold soil moisture better, which can be good and bad — depending on how important drainage or water retention is to your particular plants. Glazed pots are a little more expensive but they withstand the freeze/thaw cycles of winter much better than porous non-glazed pots.
Drainage: For healthy root development, soil must drain water properly and have space for air. Soil that is too dense can slow drainage; so can lack of a drain hole or a blocked drain hole. If drainage is slow, water may collect at the bottom, smothering the roots and the plant may die. Be sure to look for drain holes when selecting containers.
Consider shape and size
A garden container that’s too small crowds roots, stunting growth and causing the plant to become root bound. If the pot is too big, the extra soil may stay too wet and can smother the roots.
Always choose a pot that’s in scale with the plant you buy, allowing room for a year or two of root growth. As a rule, transplant a nursery plant to a container that is 2 inches deeper and wider than its nursery container.
Seasonal plants can be crowded together more closely than plants that you grow in the ground. The recommended spacing for ground planting varies and depends on the plant size and what you’re trying to achieve.
If the plants normally grow 10 to 12 inches tall, use a pot with a diameter of at least 8 inches. If the plants grow 2 to 3 feet tall, go for a diameter of 24 inches or a large container such as a half-barrel.
Improvised garden containers
You can make garden containers from all kinds of items such as broken wheelbarrows, old boots or a hollowed-out piece of tree trunk. Whatever you choose, make sure that the improvised container has proper drain holes and room for the roots to grow. If necessary, drill drainage holes. Keep in mind that small containers need water more often.
Overall, you may find that whimsical containers provide welcome exclamation points in the garden. They are creative and often encourage surprising, always interesting, comments and conversation.