Imagine a local farm producing masses of delicious, fresh, succulent organic fruit and vegetables all year round. You may live miles away from green fields, but this farm is different as it’s tucked away in the middle of your town or city! Urban farms are popping up all over the world and there are some very exciting times ahead …
Growing food in an urban environment is becoming more important than ever as populations steadily increase. A large percentage of the world’s agricultural land is used to produce animal feeds and oils, rather than food directly grown for human consumption. Considering that the majority of the population live in towns and cities, growing food in urban locations has got to be the way forward. As populations have grown, so has meat consumption. Luckily, many more people are now becoming vegan, vegetarian, pescetarian and “flexitarian” (those who eat meat occasionally rather than normally). Lowering meat consumption can only be a good thing and urban agriculture can deliver the freshest healthiest food, while cutting down on food miles and growing produce without relying on fossil fuels.
Urban farms produce fruits and vegetables, for example, herbs, salads, microgreens, sprouting salads, green leaved veggies (such as kale, chard, cabbages and spinach), tomatoes, strawberries, cucumbers, sweet peppers and mushrooms. Some urban farms raise fish within aquaponic systems (which are quite different from fish farms), and urban apiaries are thriving around the world, especially on rooftops, producing delicious local honey and products made from beeswax.
The possibilities are endless – many of the farms are indoors, for example, disused warehouses which employ technologies such as hydroponics, aeroponics or aquaponics. These indoor growing spaces use computer controlled lighting systems and many of them generate their own electricity. Some farms have been set up on brown field sites, landfills and parks using permaculture while others are designed for rooftops or even underground. Thankfully, there are a growing number of schools growing food in the middle of towns and cities. What could be better than teaching children how to grow and prepare their own food?
A large number of commercial urban farms use vertical farming methods where plants are grown on vertically stacked layers.
Some of the growing systems used today are summarised below:-
There are many types of hydroponic systems, but what they all have in common is that the plants are grown in nutrient rich water, rather than soil. The amount of water required by hydroponic systems is less than 10% of the amount used in growing crops conventionally.
The three most basic systems are Wick, Water Culture and Ebb & Flow.
The Wick system is a simple one with no moving parts and is excellent for producing herbs and microgreens. The Wick system is easy to use at home too. The plants grow in a container filled with Perlite, Vermiculite or a soilless mixture. Underneath the container is a reservoir which holds water and nutrients. Cotton or nylon wicks are inserted into the growing medium near the plant’s roots, and the other end of the wick is placed in the water reservoir. The nutrient solution is drawn up the wick and slowly absorbed by the roots of the plants.
Water Culture is also a very simple system given that the plants are suspended on a Styrofoam platform which is placed directly on top of the reservoir. The plants’ roots are immersed into the nutrient-rich water and an air pump oxygenates the water.
Ebb & Flow is more complicated as the system works by flooding the plants’ roots with nutrient rich water, then allowing the water to drain back into the reservoir. The plants are placed in a large, shallow plant tray on a stand. The tray is filled with perlite or other soilless growing medium. The water reservoir is placed directly under the plant tray and is connected to the plant tray with two pipes. A submersible pump, fitted with a timer, controls the flow of water up one pipe and floods the growing medium with water. The water then drains down the second pipe, back into the reservoir. A timer is used to control the flow of nutrients to the plants’ roots and, once the water has drained away, the roots are left to dry out. The advantage of this system is that the timer controls how often the water needs to be pumped up to the plants, which depends on what type of plants are being grown, how large they are, how many there are and what type of environment they are being grown in.
Aeroponics literally means to grow plants in air. No soil or other growing medium is used. In an industrial situation the system is carefully monitored by computers, which can control the lighting, nutrient levels, temperature and humidity. Seeds are sown onto a special cloth which is stretched over a planter. Under the planter is a chamber which contains hoses. Nutrient–rich solution is pumped through the hoses, and an aeroponic mist is sprayed upwards via nozzles onto the cloth. Once the seeds germinate, their tiny roots start to grow downwards through the cloth. As the plants grow, nutrients are increased until the plants are ready to be harvested.
As the name suggests, aquaponics uses water to grow plants, but it’s not simply a system for growing plants as fish are important in aquaponics too. The system combines hydroponics (as above) and aquaculture (farming of fish). The whole system of aquaponics is that it is a circulating, or flowing system, which benefits the fish and the plants. The fish live in a large tank. They can be Tilapia, Trout, Bass, Carp, Catfish, Koi (which is not good to eat) or even Goldfish (definitely not for eating!). The fish produce waste which is high in ammonia. Fish cannot live for long in water containing high levels of ammonia so the waste is pumped into a separate tank and filtered by bacteria using a biofilter. The bacteria breaks down the waste into nitrites. The nitrites are oxidised to form nitrates which produce fertiliser for the plants. The plants utilise the liquid fertiliser and then the clean water is pumped back into the fish tank.
The advantages of growing within all these systems are huge:-
- Year round crops
- Higher yields
- Less fertilizer
- Far less water
- Not dependant on weather
- Temperature, humidity, airflow and lighting can be controlled
- Produce is fresh and mostly organic
- Less fossil fuels as no traditional farm machinery is used
- Vastly reduces food miles as each farm supplies local people
- Potential to generate electricity
- Provides additional jobs
The farming systems I’ve described above are mainly used by commercial urban farms, but there are umpteen suppliers around the world who sell small to medium sized domestic version too. Why not try a small hydroponic system at home? Not much space is required and some will even sit on a windowsill. A leading brand in the UK is Growth Technology (who have sister companies in the USA and Australia) and their products are available in the many grow shops and garden centres throughout the UK and beyond. For more information visit www.growthtechnolgy.com
I grow sprouting seeds too, which are very easy to cultivate, highly nutritious, and cost next to nothing to set up – just a packet of seeds! Alfalfa sprouts are brilliant and will be ready within about 5 days. Pea shoots and sunflower sprouts take a little longer but are well worth it. These can all be grown in trays (even recycled plastic supermarket trays) or glass jars. Have a go and add a little zing to salad, wraps or sandwiches!
Urban farming is such an exciting idea and we need to support these projects as much as we can. Have a look if there are any in your area or whether there are any planned for the future, and if so, spread the news! These farms could potentially make a huge difference to feeding the world and reconnect people with their food.