Paignton Zoo Project
During my meeting with Alasdair Hoood at the botanical gardens last week, I learned of the Paigton Zoo Project. The Zoo situated in Paignton, England promotes the importance of sustainable use of resources and highlights the benefits that new technologies can offer horticulture and crop production. One of the ways they do this, is in their unique approach to sourcing plant-based food for their animals.
While the Zoo partly out sources its food, it grows a substantial number of crops onsite using hydroponics. The system has multiple layers of crops; which are stacked to maximize space for cultivation. While the trays are stacked, the top trays receive maximum sunlight and those on the bottom naturally receive much less. To challenge this, the system moves horizontally so that plants receive sunlight from different angles.
If a small zoo can go through 800 carrots a day, it’s not surprising that fresh feed for the animals comes with a hefty price tag of £200,000 per annual year. Hydroponics is proving a solution to reducing the cost of animal feed, while also increasing the nutrient value of their diet. Before Paignton Zoo began growing crops onsite, the idea was practiced across larger Zoos in the US where grow chambers have been used to produce green fodder for hooved animals. This was first experimented in 1968 at San Diego Zoo which used grow chambers to produce 500-600 pounds of fresh barley greens for the zebra, antelope and deer.
The Zoo’s vertical farmer highlights that wild animals need ‘wild’ food. Growing crops onsite, helps to guarantee no chemicals are used during production. It also helps to ensure animals are supplied with food authentic to theirs in the wild. Animals of a plant-based diet will eat food out with their native range- if given to them. A key thing to remember, is feeding captive animals unnatural food will translate into nutrient loss and the high concentration of foreign minerals will eventually result in health detrition. However, being able to harvest and feed the animals within minutes ensures they are receiving all the natural sugars, vitamins and minerals that lack in commercial produce. Interestingly, hydroponics allows for more control over the quality of produce grown. Not only is produce often more flavourful, but plants can also be infused with increased vitamins and minerals.
Improving the quality of feed using hydroponics, has helped to address problems such as ‘hemosiderosis’ in zoo animals. Hemosiderosis is a world-wide problem in zoos, where certain animals, no longer dining on the food of their natural habitats, consume too much iron which is stored in body tissues. This then builds up in organs such as the liver, where it stays permanently and causes severe tissue damage over time. While zoo animals can be fed commercial pre-mixes low in iron, the fresh fruits and vegetables fed to many animals as part or all of their diet typically contain more iron than is needed.
This problem is further compounded at Paignton zoo as vegetables grown locally in the deep red, iron rich soils of Devon are higher than normal in iron. Generally speaking, commercially grown vegetables produced world-wide with soil fertiliser, are expected to have a higher iron content than the vegetation many zoo animals would consume in their native environments.
Beyond the zoo, there is a very real opportunity to look at urban crop production on a commercial scale. In urban areas, a similar- if not the same hydroponic system, could provide healthy food close to the market place while reducing packaging and transportation costs, relieving the burden on infrastructure and saving energy. It could also lend itself to land that may be unsuitable for other purposes or at present not utilised such as rooftops, basements, or disused industrial sites. While vertical growing technology and hydroponics are proving to have endless benefits, I feel it is only a matter of time until they are widely used as strategies for food security and energy conservation.