Photo: BBC News

Paignton Zoo is testing a new vertical crop growing system to grow food for the zoo animals, giving prominence to new possibilities for environmentally friendly, sustainable farming.

The new vertical crop system, developed by Valcent, of Launceston, Cornwall, is a hydroponic system that rotates the plants on a conveyor belt via a "feeding station" to create airflow and stimulate growth. Valcent claim the farm will require one staff member working approximately two hours a day to keep it running, while computerized controls to regulate irrigation and water supply and the environment within the polytunnel.

This method enables the zoo to grow more than 20 times as many crops as could be grown conventionally in a field covering the same area, using renewable energy and recycled water, so that only 5% of the typical amount of water is needed. The vertical farm will reduce the zoo's food miles, and could cut as much as £100,000 from their annual feed bill, which is currently over £200,000.

"The world population is growing, food supply is shrinking, water supplies are becoming more limited, food production is competing for land with housing and the production of fuel crops. We have to make better use of available land."

"The system is designed to be 'eco-friendly' using solar power or wind energy, with the water used to grow the plants being recycled.

"It doesn't require a green field site so it can be used in urban areas, in warehouses and in deserts."

Kevin Frediani, Paignton zoo's curator of plants and gardens, said: "We can grow more plants in less room using less water and less energy."

Paignton Zoo will be providing feedback on the performance of the vertical crop system to guide future product development.

• * a micropropagated plantlet
• * a membrane which enables the plants to grow and stay fresh for 3-6 months in normal light without the need for watering
• * a reusable biome
• * a coir growing pot and compost
• * an information leaflet

• Valcent Products, developer of the vertical crop system
• Valcent company blog
• TreeHugger article discussing the vertical farm
• BBC News story about the new system at Paignton Zoo
• Devon Directory: Agriculture
• Devon Directory: Green Listings