Containers for Urban Farming
Like raised bed gardening, container gardening is an above-ground technique. Containers come in a variety of forms, are typically smaller than raised beds, and allow for the planting of only one of a few plants, and are easily portable. Containers are also often used with soilless growing mediums, such as potting mixes. Container gardening shares many of the benefits of growing in raised beds. It allows urban farmers to manage soil contamination and plant atop blacktop, concrete, or other spaces unsuitable for in-ground production. Given the portability of containers, container gardening also allows farmers an option for dealing with temporary land tenure.
Additionally, urban farmers can tap into the urban waste stream to yield a myriad of affordable container options. Riverpark Farm in Manhattan, for example, grows food for the Riverpark Restaurant in recycled milk crates. Other urban farms are planting in plastic wading pools or recycled wooden pallets.
In New Jersey, Garden State Urban Farms maintains an entirely portable farm by planting in EarthBoxes, a commercially developed container gardening system that claims to double the yield of conventional gardens. For more information about EarthBoxes, see the company website at http://www.earthbox.com/.
When choosing a container type, three main considerations are volume, drainage, and material. All containers should allow adequate drainage, without draining too quickly. For volume, the bigger is typically the better, and farmers must take into account the root depth of their crops. For materials, and particularly when using recycled or salvaged containers, it is important that they contain no toxic substances. Painted or treated wood, plastic containing solvents or high-density polyethylene (HDPE), and metals should be avoided.
The Iowa State University Extension offers a two-page factsheet on container vegetable gardening, including suggested cultivars for container production, available for download at https://store.extension.iastate.edu/Product/Container-Vegetable-Gardening.
Cornell Cooperative Extension of Rockland County also offers a factsheet on container gardening, including information on fertilizing and potting mix recipes, at http://rocklandcce.org/resources/outdoor-container-gardening.