Even before you think about what plants you’ll grow in your container garden, consider what garden pots you have on hand, what needs replacing and what you need to acquire.
Almost anything that holds soil and water will work as a container for plants, but consider practicalities and aesthetics, too. The larger the container, the more room there is for a beautiful display of plants, a well as the soil and water needed to keep them thriving. When in doubt, go big. Large containers have more visual impact in the landscape.
When considering materials, keep in mind the weight of a container once it’s filled — moist potting soil is heavy. If you’re creating a potscape above ground level, make sure your balcony can tolerate the weight load. Plastic and fiberglass are lighter than wood and concrete, but dark-coloured plastic heats up in the sun. Some plants don’t like to have their roots cooked. Terra-cotta pots are classic beauties and allow a healthy exchange of oxygen around roots, but they do dry out more quickly than containers made of more solid materials. Concrete is practical and frost-resistant, but heavy. They’re perfect for large containers that will stay in place year-round.
Whatever you choose, make sure there is a drainage hole at the bottom. When watering a container, it’s important to make sure water reaches the very bottom, otherwise roots will grow in just the top few inches. However, any excess water needs to have a way to drain away to ensure plant roots don’t rot. Covering the holes with potshards or gravel is a bad idea — it impedes drainage, rather than improving it. Potshards and gravel also take up valuable space needed for soil and root growth — both of which help plants reach their full potential. Place a square of window screening or a coffee filter over the hole before filling with potting soil to keep the soil in and allow excess water to escape.
Then there are the myriad household items that can be repurposed for container gardens — colanders, baskets, old boots, whatever. Some may need a clear plastic lining to be practical. Be sure to puncture a few holes in the bottom for that all-important drainage and trim off the top edge to just below the top of your container.
As far as aesthetics go, it’s your garden, so choose what makes you and your plants happy. However, by limiting the different kinds of container materials and design styles, you’ll create a more unified, cohesive look.