first published March 5, 2010

When it comes to creative gardening, trucks, rooftops and front doors have something in common—they’re truly inspired uses of space. Usually, we think of garden creativity in terms of plant varieties and design not usage of space. But that’s all changing. Thanks to a resurging interest in gardening (especially edible gardening) and the limitations of small urban spaces, the incentive to think outside of the window box is taking root.

Most of us think of gardens in terms of total usable square footage. But as many gardeners have discovered, length times width is only the beginning.

For example—at the risk of sounding a bit eccentric—I grew pumpkins on the roof of my house one year. The reasons were simple and, ostensibly, rational. I had no space in my traditional garden to grow gangly gourds, but I had a large flat roof that was sunny, warm and spacious. Of course, I was also intrigued by rethinking the concept of garden space. I grew the pumpkin plant in a large pot, and it thrived in its unconventional environment. Obviously, the ladder climb to the roof required a certain degree of dexterity and caution, but the point is that the space worked.

If rooftop pumpkins are too avant-garde for your tastes (or your nerves), then how about a living wreath to transform a wall or door into a work of art? Shaped like traditional wreaths, these living versions come complete with drought-tolerant succulents and soil. Simply hang them in a sunny location, and occasionally take them down to water. Succulent wreaths look great and grow in places you’d never use otherwise.

Similarly, green walls are another way to create garden space. They range from simple to complex (including watering systems) but are all basically frames filled with lightweight potting soil and plants. Green walls can be freestanding structures or secured to building exteriors. On a small scale, they’re great for growing salad greens. On a larger scale, green walls are all the rage inside new buildings because the plants add aesthetic value while filtering toxins and improving air quality.

Green roofs, the horizontal equivalent of green walls, are also becoming more common. Granted, retrofitting your house to accommodate a green roof is probably out of the question, but what about your doghouse roof? I’ve seen them used for this purpose, and the doghouses look great. Rover’s roof can be as simple as a waterproof membrane covered with potting soil, held together with chicken wire and filled with plants. As an added benefit, the plants will keep the doghouse cooler in the summer, and that makes Rover cooler in more ways than one.

Of course, don’t forget container gardens. Pots and hanging baskets are ideal for growing vegetables and ornamentals and are especially useful if all you’ve got is a balcony or patio. And there’s nothing wrong with putting carrots in established flowerbeds along side marigolds or lilies.

But if you really want to take garden creativity to a new level, think truck farm. It’s a concept that a couple of creative guys in the U.S. came up with. They took a half-ton truck, drilled some drainage holes in the box, added soil and grew vegetables. Truck gardens are just like other container gardens…well, except these gardens sit on the street and can be driven around town. As crazy as a truck farm sounds, there would be some definite benefits. For example, if you grew tomatoes in the back, you could just wheel the truck inside a garage or parkade during inclement weather to protect the plants. In addition, you could dramatically increase tomato yields by parking indoors at night, which would provide extra nighttime warmth for the heat-loving tomatoes.

Now, before you decide some of these ideas are a little too strange for your taste, consider something that French writer Bernard le Bovier de Fontenelle said: “The magnificent and the ridiculous are so close that they touch.” I’m guessing he probably had a pumpkin on his roof too.