Hesperian Health Guides
Sustainable Farming in the City
HealthWiki > A Community Guide to Environmental Health > Chapter 15: Sustainable Farming > Sustainable Farming in the City
More and more, people are creating farms and gardens in cities to feed themselves, to create jobs, and to keep alive their knowledge and traditions of working the land. Creating green spaces with crops and trees also improves the air in cities, and reduces illnesses caused by air pollution, such as asthma. Turning the empty spaces that often become trash dumps into farms and gardens makes a city healthier and more beautiful.
Contents
Adapt farming methods to smaller spaces
- Grow plants upward on stakes, walls, or other supports. The sides of buildings can be good places for climbing plants.
- Grow food crops on rooftops and balconies, in buckets, bags, tires, tin cans, and old baskets. You can use any container that has a hole for water to drain out. Leaf crops such as spinach and lettuce, and vegetables like tomatoes, peppers, and eggplant, grow well in containers. Bananas, figs, pygmy date palm, pineapple, dwarf citrus, and dwarf mango also grow well in containers.
- Garden beds as shallow as 20 cm deep can be filled with organic matter such as corn husks, rice or cocoa hulls, leaves, or even shredded newspaper. Plant seedlings with a small amount of soil into holes in the organic matter and their roots will spread. Over time, the organic matter will turn to soil.
| A rooftop garden |
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- Make raised planting beds by double digging or by piling soil 1 meter deep on top of concrete surfaces and enclosing it in large containers.
- Sow seeds or seedlings closer together than usual. Plants grown this way will adapt to the close spacing over time.
- Grow more than one crop together in a small space.
- Replant a new crop immediately after harvesting the previous one.
How to double dig a garden bed
To grow as much as possible in a small area, or to plant on hard soils or soils with little organic matter, double digging is a good method.
- The edges of the planting bed should be just wide enough across so that 2 people can kneel at the edges of the bed and touch hands in the middle. The bed can be as long as you need.
- Loosen the top of the soil and spread finished compost or manure on top of the whole bed.
- Starting at one end, dig a ditch across the bed 30 cm deep and 30 cm wide.
- Use a digging fork or shovel to loosen the soil at the bottom of the ditch and add some compost or manure to it.
- Dig a second ditch across the bed. Put the soil from the second ditch into the first ditch. Loosen the soil at the bottom, and spread compost or manure.
Continue until you have dug the entire bed. The loose soil will rise above the surrounding soil. Make the bed smooth and flat, with the edges angled so that water and soil do not run off. Add a layer of sifted, finished compost to the top of the bed. Now it is ready for planting.
After you have prepared the beds, you should not walk on them because this compacts the soil. If you double dig a plot once and add natural fertilizer every season before you plant again, your soil will stay healthy and loose for many years.
Contaminated soils
Soil in cities may be contaminated with toxic chemicals, such as lead from paint, gasoline, and old batteries. These can all cause serious health problems. To know if your soil is contaminated:
- Find out how the site was used in the past. If it was a factory, gas station, parking lot, or waste dump, the soil is probably contaminated.
- If the soil smells like chemicals, it is probably contaminated.
- Areas underneath painted walls are most likely contaminated with lead.
Soil samples can be tested at a university, extension agency, or private laboratory. Lead tests are not expensive, but testing for other contaminants is often difficult and expensive.
Planting safely in contaminated soil
You can still grow food safely on contaminated soil. One way is to cover the soil with a layer of hard packed clay or concrete. This seals the contaminants in. Grow crops in containers or shallow beds on top. It is safer to grow fruit crops (such as tomatoes) on contaminated soils because they absorb fewer toxins than leaf crops (such as spinach) and root crops (such as carrots and potatoes).
Urban farming blossoms
Cuba is an island nation that once produced large sugar and tobacco crops for export. It had an industrial system of farming, relying on petroleum fuels and petroleum-based agricultural chemicals. When the Soviet Union collapsed, Cuba lost both its largest petroleum supplier and its largest buyer of sugar and tobacco. Because of political disagreements, most countries would not sell chemicals to Cuba or buy Cuban products. Cuba was forced to find a new way to grow food.
Cuba made sustainable farming their new national policy. It promoted sustainable methods through land grants, education, and by setting up local markets. As the new methods developed and spread, there was more healthy food for everyone.
As in other countries, many Cubans moved from the countryside to the cities. Now the government encourages people to grow food in the cities using sustainable methods. Urban farming promotes good nutrition, and provides jobs and education. Most of the fresh produce (vegetables, poultry, flowers, and medicinal plants) used in Cuba’s capital city of Havana is now grown in or close to the city. Plant medicines grown in Havana are sold at low cost in shops called ‘green pharmacies.’ Although brought on by a crisis, sustainable farming has changed Cuban people’s lives for the better.