The popularity of our recent articles such as downsizing; sustainable cities and low-impact transport options proves that permaculture is not merely a solution for smallholders, farmers and families living in the countryside, but for city dwellers too. Living in cities offers great opportunities for us to reduce our footprints.
This may seem like a misnomer but think about mass transit; high density living; the potential for sharing tools, equipment and facilities; and a wealth of community and entertainment options available on your doorstep.
The perception that cities are a carbon hungry way of life lays largely in the footprint associated with transporting food and other provisions to geographical areas which do not provide for their own subsistence needs. But this isn’t a reason to give up the joys of city life just yet. In this reader solution we look at more ways to encourage food security in urban areas.
Why choose raised beds in an urban setting?
How about introducing a raised bed in to your community growing space? These are easy to get started and have so many incredible benefits, such as:
- Increasing the yield of food from a small space
- Absorbing rain water, releasing it slowly over time, reducing the pressure on storm drains and aiding in flood protection
- Using up waste from garden clearing, thus reducing disposal costs
- Creating a community space which can be used for adult and child education, or as a sheltered chill out space – the raised beds can provide a barrier to city noise pollution
- The beds can be arranged to create a visual barrier to an unattractive urban landscape
- Being suitable for growing all kinds of vegetables
First, creating your raised bed...
Raised beds should be at least 1-1.5m high. This allows for a fantastic increase in growing space, whilst ensuring that most adults will be able to harvest the food without treading on the bed and compacting the soil.
Observe the wind direction, and plan to develop the bed as wind break, so running with its length at right angles to the wind direction.
A trench should be dug (great opportunity for getting the community involved), and filled with garden waste which will rot slowly and release nutrients over time. The life expenctency and potency of nutrients depends on the type of waste you put in – if you use chipped wood (which breaks down quickly), a large amount of nutrients will be released in the first year.
To make the most of this, Sepp Holzer suggests “selecting plants that demand a very high nutrient content: pumpkins, courgettes, cucumbers, cabbages, tomatoes, sweetcorn, celery and potatoes to name a few. In beds like these it is better to cultivate less demanding plants like beans, peas and strawberries after three years. If they are planted any earlier they might become overfertilised, and not develop a good flavour.” Where you are able to use fallen tree trunks these will rot down very slowly, providing nutrients to the soil slowly over time.
If you can get hold of it, cover the material you want to decompose with a layer of turf, grass side down, and cover this with the material you excavated. The slopes should be at least 45 degrees, and up to 60-70 degrees if you want to increase the growing space in a constricted area.
Many raised beds ‘fail’ because they are less steep than 45 degrees. This leads to compacting of the soil, so new plants cannot establish themselves as well as they would in loose soil. It also restricts the amount of oxygen getting to the decomposing material, resulting in anaerobic rotting, which will smell unpleasant and have a negative affect on the plants.
Here is a simple table of dimensions, to save you the trigonometry!
Next, planting the bed...
The beds should be planted immediately while the soil is still loose. Raised beds are suited to growing all kinds of vegetables: peas, beans, salad, tomatoes, radishes, cucumbers, carrots, courgettes, pumpkins, potatoes and many others; with fruit bushes growing very effectively on the crest of the bed. If you wish to use the raised bed as a windbreak, make the sides steeper (60-70 degrees) and plant the top with tall plants such as sunflowers, hemp and Jerusalem artichokes.
As ever, mulching with straw, hay or newspaper is an effective way of keeping away the plants you don’t want, and also ensures that moisture is retained in the soil. This will reduce the need to water the bed in dry periods, ensuring low maintenance.
Depending on the weather and how they are used, the raised beds flatten gradually over the years. They are then either rebuilt or replaced.
Finally, encourage food growing in your community...
As Sepp notes in Sepp Holzer’s Permaculture, “an appropriately designed raised bed system can make an excellent and relaxing pick-your-own area. By harvesting food for themselves, the visitors feel connected with nature and can convince themselves of the high quality of the produce.” You can invite schools to your growing space so that children and teachers alike can learn about the potential of sustainability in urban spaces.
Other members of the community can be invited on work days, especially useful when digging the trench and filling it with garden waste. Why not let your helpers come back in a few months and reap the harvest of their efforts?
Where you have the space, raised beds can be arranged to create a maze or around a central focal point like a pond or orchard.
Produce can be sold to raise revenue for the project, and the area will be adequately sheltered from traffic to provide a relaxing oasis in an urban setting, or the perfect location for a community party!
Emily Ingham is a former environmental consultant.
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