Container Gardening basics
With the rising popularity of gardening in containers, anyone can have a beautiful garden, no matter how small their space. The rules are much the same as gardening in the ground, but container gardening can be easier, in many ways. Here’s how to get started.
Almost any container will work: terra cotta, glazed or plastic pots, wine barrels, cedar boxes, metal buckets, even old shoes! The container needs to hold enough soil for the plants you want, and it must have drainage holes for excess water to drain. For most containers, drain holes should be 1/2” diameter. Please be aware that some metal containers can become extremely hot in the summer sun, possibly causing root damage. Consider shading or even insulating them.
Think about where the drainage water goes — use pot saucers to prevent staining on patio or deck surfaces (or dripping onto your neighbors below) but don’t let your pot sit in excess water. Some apartment gardeners place their pots on a rack over a bucket or small tub when watering, then reuse the water or dispose of it. Larger containers can be set on pot feet, bricks or blocks to help drainage and keep the bottom dry.
Almost anything can be grown in a container: trees, shrubs, vines, bamboo, perennials, ferns, grasses, bulbs, tomatoes, etc. Large, fast-growing trees or shrubs may need to be transplanted or replaced after a year or two, but you can experiment. Combine different types. You can change out the flowering annuals when they’re done while perennials or larger permanent plants lend structure and interest throughout the year.
Consider height, color and texture when you combine plants. Varying these elements will give your container garden more depth and creativity. Need ideas? Swanson’s has many display containers year around to inspire you, or our staff is always happy to suggest some combinations to get you started. And there’s no shortage of ideas in books and magazines out there.
Swanson’s plant signs, tags and our friendly staff can help you determine the overall growing requirements of specific plants.
Your choice of plants, of course, depends on the amount of sunlight you have. If you have containers sitting in a variety of light conditions, choose plants which fit each area best. Group plants with similar light requirements together.
For most plants, use a high-quality, general potting soil. Swanson’s carries several quality brands. Some plants need fast drainage and a more sandy medium for planting; others specifically require an acidic soil. Do not use soil from your garden. It tends to compact too easily and may introduce disease.
Watering will vary according to individual plants, pot size and weather. Some plants like to be kept evenly moist. Some prefer to dry out somewhat between waterings. Very few want to be wet all the time. Plants in terra cotta clay pots should especially be watched because the pots are porous and therefore dry out faster (unless they are sealed or glazed inside).
Before adding more water, feel the soil one inch below the surface with your finger to see if it is dry. Check daily during the summer, as containers tend to dry out quickly. On a hot day in full sun you may need to water twice. Watering in the morning allows leaves and soil surface to dry, helping to prevent disease and viruses. Always apply enough water so that some drips out the bottom (please see the earlier note about saucers).
Fertilize as needed during the growing season. Heavy blooming annuals benefit from bi-weekly applications of a water-soluble fertilizer, such as 20-20-20. Woody perennials, shrubs and trees prefer a treatment of a granular, organic, all-purpose plant fertilizer once or twice a year. Always check product labels for instructions. Avoid over-fertilizing, and never fertilize a plant which is extremely dry.
Most container plants benefit from repotting every few years. This allows you to cut back roots which are root-bound (growing tightly against the wall of the pot) and refresh your potting soil. Repotting is best done in winter or early spring. Large pots may be accessed by tipping on their side over a tarp or piece of cardboard. Ask one of Swanson’s staff for advice on which plants may need repotting and how to do it.