Tips for Container Gardening

By Peter Sandercock

Container gardening is a great way to make gardening manageable, add colour to your patio or yard and just a way to unwind and enjoy a bit of nature.

Maybe it is because with just a few plants you can transform a small deck or patio into an attractive garden. Or perhaps it is the flexibility and mobility of the containers. You can move them to suit the season or your mood or to brighten up a corner that needs a “little something extra.”

Long gone are the days of plastic pots filled exclusively with geraniums, petunias and lobelia. Although these are tried and true plants that flourish in our growing conditions, Canadian greenhouses are producing many more contemporary plants with new varieties available every year!

Pot Particulars

Plants need room to grow, so choose a container that will accommodate the plant’s root system and allow it to grow to its full potential. Unglazed terra cotta pots dry out more quickly than glazed ceramic pots or plastic containers. No matter which type of pot you use, be sure there are ample unblocked drainage holes for water to escape through. Most plants don’t fare well if water-logged.

The Dirt on Dirt

Vermiculite, perlite and sand keep soils light and well drained. Peat helps soil retain water. Use a blend that provides the right combination of drainage and water retention for healthy growth. You can use soil from your garden, but if it is too dense, your plants will not thrive. You may also have to battle weeds.

For best results, use bagged soil or a soiless mix (available at your local greenhouse) designed especially for containers. It is also a good idea to change the soil each year to avoid disease and allow your plants the best opportunity to flourish. Some mixes contain water-retaining soil additives that will soak up water then release it slowly back into the soil. This is a great idea if you are busy and are worried about missing a watering. Be sure to leave about two inches of room at the top of the pot when planting to hold water. Without that extra space, water will run off the soil before penetrating to the plant’s roots.

Location, Location, Location

The first step in creating your container garden is to decide where you will be placing the arrangement. Is it in full sun or shade? Is there easy access to water? Is it a windy location? Answering these questions will help you focus on the best plants to choose for the location. For example, you would not want to place full sun plants in the shade or a flower with delicate petals in a windy spot.

Colour Me Beautiful

Thinking of location will help you decide on what colour combinations would be spectacular in your garden. Perhaps you want to match the colour of your home, complement a garden feature or present a particular style. For an arrangement that has a simple elegant style, choose flowers or foliage that are similar in colour. For a more dramatic effect, choose complementary colours such as orange and purple, or yellow and blue.

Picking Plants

Choose plants with similar growing needs. For example, group varieties that prefer full sun together. For best results, start with quality plants. With our short Canadian growing season there is no time to nurse low-grade plants back to health. Greenhouse growers take a lot of care in growing plants that thrive in our climate. They are also knowledgeable and a great source of information when choosing what to grow and where. When choosing a transplant, look at the roots to make sure that the majority of them are actively growing. Active roots will be white in colour while old roots are brown or even blackish.

A new trend is to plant all foliage plants and to use perennials and grasses to add texture. Many people are planting perennial hostas or ferns in their planters and then replanting them into their gardens in the Fall.

Composition:

Traditional container gardening usually included a dracaena or spike in the center of the container and a geranium on either side of it with two similar trailing flowers across from each other resulting in a very symmetrical look. More and more consumers are planting asymmetrically. This allows you to try more plants in a pot as you usually only plant one plant rather than two across from each other. Further, most baskets are not seen from all sides so the new trend is to plant a tall spike or grass at the ‘back of the pot’, then two to three medium size plants such as coleus or geraniums or begonias and then two to three trailing plants such as potato vine, bacopa or vinca vine.

Water Works

Does the plant really need water? A lack of water is not the only reason your container plant’s leaves may wilt in the summer. Always test the soil. Stick your finger down two to three inches to check for dampness before watering. If dry, water the plant until water runs out the bottom of the container. If your soil seems adequately damp, but your container plants still seem stressed, try moving them to a cooler location. If your container has dried out completely and the water runs down the inside edges of the pot instead of soaking in, submerge the container into a water-filled sink or large bucket and let the soil soak until rehydrated. Rainwater is the best water source but not always readily available. If you are worried about water quality, have it tested. High salt levels provide nothing but problems for container gardening.

Plant Food

Flowers flourish when fertilized. New varieties in particular depend on plant food to thrive. If you have trouble remembering to fertilize, use a well-balanced slow release fertilizer that is released every time you water. What is the best plant food? To encourage lush foliage growth and lots of blooms choose a fertilizer with a slightly higher percentage of nitrogen (first number) in the mix. Most greenhouses use a slow release fertilizer in all of their planters and then we also use a soluble fertilizer when watering.

Our Favourite Plant Picks

✿ Ivy Geraniums

These are highly underrated plants that make great hanging baskets. Not only are they showy, but they are also tough enough to stand a windy day and if you miss watering them, they are more forgiving than a basket of petunias.

✿ Coleus

Everything old is new again. Growing up, I remember pots of coleus in my mom’s house. Now they are all the rage in foliage containers. Every season there are more and more varieties of these jazzy plants.

✿ Ipomoea

These varieties, sometimes called potato vine, are popular in all foliage arrangements. They come in light green, purple and bronze.

✿ Grasses

Over the past couple of years, the number of grasses available to gardeners for container planting has doubled annually. They range in height, colour and texture. Grasses are a great replacement for spikes or dracaena.

✿ Heuchera

A perennial also known as coral bells is one of the hottest plants recently. The reason is the foliage, which can range in colour from deep purple to peach to lime green to pink.

✿ Lamium

These flowers have very interesting foliage and are great combined with petunias. Not only do they support the petunias but look great doing it! Lamium is another perennial so you can plant them into your garden in the Fall. They make very hardy ground covers.