Container gardening: Thrillers, fillers and spillers

COLUMBIA, Mo.– If you’re yearning to grow flowers or vegetables but are short on space or have limited mobility, University of Missouri Extension horticulturist David Trinklein suggests giving container gardening a try.

Container gardening allows for creativity in a small space and, since plants can be moved inside in the spring and fall, lets gardeners extend the growing season, Trinklein said.

Additionally, container gardens are less prone to disease and insect infestation than traditional gardens.

“Gardeners have discovered that containers filled with vibrant colors can create a dramatic effect,” he said. Garden containers can supply an abundance of fresh vegetables in limited spaces. Apartment dwellers and older gardeners especially appreciate the advantages of container gardening.

“Containers give you more ‘bang for the buck’ than beds and borders, especially in high pedestrian traffic areas,” Trinklein said.

Container gardens include miniature gardens, window boxes, planting bags, hanging baskets and containers such as clay pots and old whiskey barrels.

There are new varieties of vegetables developed specifically for container gardens, such as On Deck, a dwarf sweet corn suited for urban and small-area gardeners.

Trinklein offers some tips for those interested in container gardening.

• Containers. Pick a container that you can move around—into and out of the sunlight or from the front yard to the back yard. Containers should be at least 2 1/2 quarts, light in color, sturdy and durable. Clay pots “breathe” the best, letting air get to the roots. Plastic pots generally will confine the root system. Galvanized pots can be highly toxic to plants, but if you want to use one for decoration, put a plastic pot inside it.

• Soil. Use a soilless growing medium such as a combination of peat, vermiculite and perlite. Find a medium you like and stick with it. Resist the temptation to buy whatever is on sale, as brands of growing media differ in amount and quality of ingredients. For most settings, soil is not a satisfactory container medium. It tends to lack the drainage of soilless media and brings weed seeds and disease pathogens to the mix.

• Fertilizer. Because they do not contain soil, container gardens need more fertilizer than traditional gardens. Use water-soluble fertilizer that contains all major nutrients. It is best to use continuous liquid fertilizing. “Just like we like a couple of meals a day, so does a plant,” Trinklein says. Feed with a dilute nutrient solution every time you water, or use a slow-release fertilizer.

• Sun and shade. Plants have different requirements for sun and shade. If you have a choice, choose morning sun over afternoon sun. Morning sun dries the leaves and reduces the chance of fungal infestations. Check pots that are in the sun daily, and even more often on the hottest days, as pots dry out quickly.

• Water. More plants are killed from overwatering than underwatering, though containers dry out more quickly than beds or borders containing soil. Water-absorbing crystals can help reduce moisture loss. Some experts recommend leaving at least two inches of room between the top of the soil and the top of the pot to allow the gardener to fill the space with water and move on to the next pot.

• Design. Trinklein says that for maximum effect, flower container gardens should include three items: a thriller, a filler and a spiller. The thriller, or focal point, might be an unusual or bright upright plant or flower. The thriller’s color should dominate the container. A filler could be a lower-growing, less vibrantly colored plant. The spiller is a trailing vine or flower that spills down the sides of the container.

• Good neighbors make good container gardens. Choose plants that will not crowd each other and that have the same requirements for light, soil, temperature and water. Tropical plants are usually good choices for container gardens, Trinklein said.