Gardening Articles: Edibles :: Vegetables
The DiMeglio System
by Scott Millard
J.D. DiMeglio loves his fresh vegetables. His English and Italian background and corresponding love of cooking give him cause to enjoy growing a varied selection of salad greens, tomatoes, peppers, herbs and more on his 250-square-foot plot in Tucson, Arizona. Although J.D. has had tremendous success with his garden, the extensive animal population in the rugged hills surrounding his rural home was also reaping the bounty. Too much bounty. Efforts at building small cages and using various scare tactics proved futile, and the rabbits, squirrels, birds and other creatures continued to plunder his garden. But J.D. is tenacious and has a talent for designing and building. Gradually, a system for protecting his crops began to take form.
Building the Structure
After numerous sketches of shapes and designs, J.D. decided to build a 15- by 15- by 8-foot metal structure that would completely enclose the garden. He considered using wood, but it warps in the desert sun, plus exposure to moisture would promote rapid decay. PVC pipe is more durable than wood and less expensive than metal, but not as attractive. He settled on 3/4-inch square metal tubing to create a strong, permanent support skeleton that could handle the weight of an irrigation system. J.D. purposely chose metal over galvanized pipe because it would age and rust so the structure would take on a natural rusty brown cast, blending with the surrounding landscape.
The first step in building the structure was installing the 6-inch-deep, 12-inch-wide footing for the 18-inch-high concrete-block wall that would serve as a foundation and form a large raised bed for the garden's soil. (Make the footing deeper if you live where gophers or ground squirrels are a problem.) After the foundation was complete, J.D. added enough amended soil to fill the planting area
Next, the metal tubing was cut to appropriate lengths. Upright supports were bolted into the masonry wall. The remaining lengths of tubing were welded together to form the structure. As an option, they could be pre-drilled and bolted together, much like a life-size erector set.
The irrigation system was designed to water plants from overhead, simulating rainfall, a resource often in short supply in Arizona's Sonoran Desert. It was constructed from class 200 PVC pipe and painted brown to slow UV degradation and to blend with the metal structure. The drip system was connected to an irrigation controller programmed to meet the day-to-day and seasonal needs of plants.
The pipe was installed on the "ceiling" of the structure to eliminate the possibility of severing a supply line with a hoe or shovel, a common problem with drip irrigation. Nine spray heads were installed at evenly spaced intervals to provide rainlike applications of water.
Once the irrigation system was completely installed, it was time to cover the structure to keep out the birds and other animal pests. Chicken wire wired to the support framework was quick and inexpensive to install. Trellises tied to the ceiling and walls where needed support vining crops such as beans, peas and cucumbers. Going vertical with these crops saves valuable garden space.
With amended soil in place, and the irrigation system up and running, all that remained was planting. In southern Arizona's mild-winter climate, J.D. plants two gardens a year: Cool-season crops usually go in sometime in September; warm-season crops gradually make their appearance (replacing early maturing cool-season vegetables)in March.
J.D. uses various coverings to extend both garden seasons. To prolong the harvest of warm-season crops, he covers the structure with floating row cover material, creating a temporary greenhouse. Using the irrigation system on timers throughout cold evenings also helps raise temperatures. If very cold nights are forecast, he sometimes fires up a kerosene space heater to help tender plants the night. Likewise, a shade-cloth covering helps extend the harvest of cool-season crops as temperatures warm in late spring. It also prevents sunscald of tomato and pepper fruits by reducing the sun's intensity and serves a a windbreak.