Q: I'd like to grow my own food. I live in Scottsdale, Ariz., on a 2.4-acre lot. I'm fascinated by urban farming. 1) What are the most nutritious foods I can grow, appropriate to the climate here in the Phoenix area, maximizing use of space, ease of farming (I am free weekends and evenings, but I'd prefer not to spend the whole time in my garden), and I'd like to have a variety of food year round. 2) Could you design a modular raised "parking lot" garden for the Southwest, where covered parking is coveted and weather accommodates year-round farming?
Asked by Tom Nelson, ’93, Scottsdale, Ariz.
Biointensive method
The super-efficient biointensive method of farming utilizes double-dug raised beds, intensive planting, composting and companion planting.
Double-dug raised beds can improve soil texture, allowing for excellent root growth and nutrient transfer from the soil. There's no big secret—double digging just means digging down to loosen the soil to a depth of 24 inches. First you need to dig out a 12-inch depth of soil, and then loosen the 12 inches of soil below the dug out layer with spading fork before replacing the first layer of soil. Despite the fact that no soil has been added, the bed will be raised due to the loosening. Preparing a raised bed takes a lot of work at first—as much as 6 to 12 hours for a 100-square-foot bed the first time. After the first crop, however, much less work should be required as the soil texture improves, according the book How to Grow More Vegetables.
For small spaces—and with this much effort, you're going to want to start small—using the space efficiently is very important. Intensive planting maximizes land use by placing seeds in a diagonally offset or hexagonal spacing pattern, rather than in straight rows.
An example of hexagonal spacing. (Illustration: How to Grow More Vegetables, Jeavons 2006)Big, healthy crops require fertilizing and fighting pests. But massive use of pesticides and fertilizers will result in negative impacts, such as killing beneficial insects, and nutrient runoff into the environment, and a lot of extra expense. Composting and companion planting can help to solve this problem.
Composting could be a SAGE answer of its own, but the basic idea is to take your yard waste, your kitchen scraps and some soil and let them all rot together into a healthy, organic, natural fertilizer. We're still waiting for our first composting question but you can get the basics down here: How do I make my compost?
Companion planting means growing different plants together to let them assist each other in nutrient uptake, pest control and pollination. For example, lettuce grows happily in the shade under young sunflowers. Nasturtiums attract caterpillars, and can act as guards—and a sacrifice—if you plant them around vegetables such as lettuce or cabbage. This Companion Planting Chart can help you find more about which plants like to grow with each other.
Benefits of urban farming?
Urban farming is generally a sustainable practice, with the ability to reduce overall carbon footprint and resource use. To get to urban supermarkets, our food makes its way through a complicated system: from production, sometimes across the country or around the world, to processing, marketing, distribution and finally consumption. But for people who grow their own food, the process is much more direct: vegetables are taken directly from the land to the table, cutting out steps and carbon along the way. And it can help cut your grocery bill too so long as you're not spending too much on fancy gardening equipment and chemicals. In addition, individuals can have more control over the kinds and quality of food they eat.
The carbon footprint for transportation of food is significant. The average distance for food to travel from conventional sources to the institutional market in the United States was 1,500 miles, according to a food miles study by the Leopold Center for Sustainable Agriculture at Iowa State University. Industrial food processing uses energy and wastes natural resources as well. For instance, I always wash the "triple washed" organic lettuce because sometimes there are bugs on the leaves. Even though the bugs prove the lettuce was not treated with pesticide, I still must rinse them away. It is really a waste of water to wash the vegetable four times, but the "triple washed" lettuce is the only organic one I can find at my local grocery store. One great advantage of growing your own food is that you will care more about the safety of your food. Therefore you will try to decrease the use of harmful pesticides and fertilizers.
Urban farming also brings you a healthier life. A recent paper from the Community Food Security Coalition's North American Initiative on Urban Agriculture reported that gardeners ate more vegetables more frequently and they consumed less sweet foods and soft drinks. Working with plants brings joy to people, too. As a poor student living in the expensive Silicon Valley, I don't own a garden. But I do keep some indoor plants. The green color always gives me so much pleasure. Not to mention the satisfaction I get when I see them grow larger and stronger. I believe growing and harvesting from a personal garden can bring great happiness to your life.
Urban farming benefits food security
Urban farming can also be a way to help the Americans who don't have safe access to healthy food. Hunger seems like it wouldn't be much of a problem in America, but 5.7 percent of U.S. households—about 12.1 million adults and 5.2 million children—had very low food security during 2008 as reported by USDA. Very low food security means in the preceding 12 months, an individual had no food to eat for an entire day because they lacked the money to buy it.
In the United States, there is a huge unrealized potential for urban gardening. A study by Community Food Security Coalition, indicated that small well-tended plots, as little as 1,000 square feet each, can provide a household's total yearly vegetable needs, including much of the household's nutritional requirements for vitamins A, C, and B complex and iron. In the president of Earth Policy Institution Lester Brown's book Farming in the City, he mentioned that Chicago has 70,000 vacant lots and nationwide, vacant lots in cities total in the hundreds of thousands. Urban farming not only makes people stronger by putting their food security into their own hands, it can also, as Brown cited from Urban Agriculture, turn "the weedy, trash-ridden dangerous gathering place—into bountiful, beautiful and safe gardens. . . ."
Jingshi Wu is a PhD candidate in geology.
