There will be major constraints in the future for urban and peri-urban agriculture due to the lack of suitable land and of fresh water. As cities increase in size, the need to source food from further away will increase, posing not only transport problems but also post harvest difficulties.
Plant factories offer the potential to produce fresh vegetables close to the centres of population (cities) where they are to be consumed.
Plant factories are sometimes described as vertical farming, with exotic architectural pictures of people and crops in large well lit buildings. Nothing is further from the truth. The plant factory of the future is likely to be a utilitarian building, (maybe even a skyscraper), filled with plants and managed by a minimum of operators.
Plant factories offer the potential to be very efficient in terms of land footprint (an important factor in mega-cities were land will be at a premium) to be water efficient, and to be able to produce crops on demand. Because it is grown in a sealed container it will be possible to use high levels of carbon dioxide to speed up growth, and also much longer periods of photosynthetic lighting. Product will be free from pesticides, and have a very low microorganism count, so will be extremely safe, and not require washing etc prior to consumption.
Initially it is predicted that plant factories will be used for high quality seedling production, but over time these are likely to develop into production units producing leafy crops, strawberries and eventually the fruit vegetables.
The big gap in our knowledge is what is the optimum light levels (wavelength, duration and intensity) temperature and carbon dioxide in which to grow these plants.
Some results from our initial studies undertaken using LED lighting, different carbon dioxide levels and different air temperatures will be presented for the growth of both lettuce and cabbage seedlings.