Professor Toyoki Kozai and Dr Eri Hayashi have had a major influence on the advancement and global understanding of vertical farming. Future Farming asked them four questions about their new book ’Advances in plant factories: New technologies in indoor vertical farming’, published by Burleigh Dodds.
The book provides a review of the latest research in the development and application of plant factories with artificial lighting (PFALs). It assesses the environmental impact of urban vertical farms and how the use of energy and other resources can be optimised to minimise this impact.
The book also considers the application of machine vision, plant phenotyping and spectral imaging in plant factories to monitor plant health and growth. There are several case studies of businesses from North America, Europe, and Asia, with different business models and technical features for commercial production of multiple crops.
What are examples of important advances in these indoor vertical farms or PFALs?
One example is the drastic improvement of electricity-photon conversion efficacy and cost performance of white LED covering a wide range of wavebands. Using W-LEDs, the electricity consumption of the cultivation room was almost halved compared to fluorescent lamps, and the spectral distribution (ultraviolet, blue, green, red, and far-red) of light sources could be adjusted to meet the purpose of plant production.
Another example is interdisciplinary research on plant factories with artificial lighting (PFALs). This research has started in several countries by natural and social scientists, economists, engineers, administrators, business people, and policymakers. Articles on PFALs are included in some supplemental readers used for educational purposes in schools. The number of papers published in related journals has been increasing exponentially since 2017.
And public acceptance of PFAL-grown (pesticide- and herbicide-free, and ultra-water saving) vegetables locally produced for local consumption has been slowly but steadily prevailing in Japan and limited regions in Europe, America, and Asia.
What do you consider to be the biggest challenges of vertical farming?
We have described several methods and strategies for challenges in the book. Some examples are:
To what extent will vertical farming compete with open cultivation, for example with fruit and vegetables and perhaps bulk crops such as grain, soy or corn?
The PFALs using white LEDs (W-LEDs) were probably first built for commercial production in 2016. So, the W-LED PFAL technology has a history of 7 years, and is at an infant stage.
The production of berries such as strawberries and blueberries in PFALs will be widely commercialised after their breeding is suitable for production in PFALs (probably by around 2030). PFAL berries do not compete with the open-field berries because they belong to different classes/kinds of produce for different markets.
Some portion of medicinal plants (herbs), head vegetables (e.g., cabbage) and root vegetables (e.g., carrots), and ornamentals (e.g., dwarf orchids, bedding, and interior plants) will be also be commercialised after their breeding is suitable for PFALs.
Bulk crops such as grain, soy, and corn for open cultivation can be efficiently bred in PFALs by cultivating them under various environmental conditions 3-4 times a year. On the other hand, the cultivation of bulk crops as food and feed mainly for taking calories is not justified. Not only because of commercial unprofitability but also because of huge amounts of heat energy generated during the cultivation. Such bulk crops will be commercialised if they are sold as healthcare products with some medical functions (not as staple foods for calories).
What are some important lessons we have learned so far from operational and shuttered vertical plant farms?
In many cases, shuttered PFALs could have been better designed and managed with respect of sanitation control, emergency control for partial and total power failure and malfunction of main environment control units, and risk management for sudden changes in demands due to social and weather issues.
Operational PFALs tend to be well designed and managed with respect to marketing and risk management tools, resource supply and waste processing, and monitoring and control of produce quality for food safety, consumer demands, and sustainable plant production.