by Charlene Burgi
Container gardening is chosen for various reasons. Some gardeners live in condominiums or apartments with only a small balcony but a burning desire to play in the dirt. Others yearn for a spot of color on a patio, or wish for edibles closer to the kitchen, or find too much hardscape exists for their planting needs. Still others, such as yours truly, have oodles of planting areas, but choose to plant some things in containers in hope they will be out of the reach of wild nibbling critters—or up and out of the way of two rambunctious puppies. And roof gardening is the granddaddy of all container gardening and brings the thought process to a whole new level!
Note that whatever space we choose to garden (other than in the ground), it comes with a higher maintenance plan. Consider the weight you are adding to your structure if you are planting on a rooftop or balcony. Soil is heavy, so add a soilless mix to your containers to reduce the weight. Water also weighs a lot. One gallon of water weighs slightly less than 8.5 pounds—multiply that by the amount of water needed to sustain your plants! Roof gardening requires a heavy-duty, moisture-proof membrane, and containers need some type of tray to catch excess runoff, or the potential patio furniture below may be the recipient of irrigation overflow.
And, speaking of water, how are you planning to water the containers? Some people run drip tubing to each planter, while others carry filled cans of water to their plants if hose bibs are not available. In this case, patios with many containers require a lot of schlepping as contained gardens dry out faster! To help reduce your labor, consider adding polymers to the soil to retain moisture for a longer period of time. Mulch the containers to prevent additional evaporation and add pebbles to the tray beneath to increase humidity around the plant. Use double-walled planters that act as insulators from heat and cold. This type of container is also much lighter than ceramic, clay or wood.
This brings up another point—hydrozoning is critical. Choose plants that do well in the existing conditions. Sun exposure must be carefully considered when choosing plant material for roof or containers. Attempting to grow a shade-loving plant in afternoon sun could be disastrous, as would deep-rooted plants on a roof garden. Native, low-water-using plants with shallow roots are best for roof gardens. If you are mixing plants in the same container, make certain they have the same water needs.
Containerized plants also deplete soil nutrients faster than if planted in the ground. I was thinking about this very thing as I mixed up some organic fertilizer and compost tea the other day for the containerized blueberries. Some plants require more feed than others, such as roses, fuchsias, fruit-bearers and vegetables. Be certain to use a good organic fertilizer once a month to optimize growth, fruit and flower production, and the plant’s well-being.
Despite the added work and thought process that comes with container planting, there is nothing more rewarding than having a fresh herb garden growing in a container right outside the kitchen door, or gazing upon the splendor of a window box overflowing with color, or popping cherry tomatoes into your mouth as you lounge on the patio. The payoff from this kind of maintenance is priceless!