Originally published in Issue 6
Japan’s plant factories are expanding to meet the increasing demand for safe, pesticide-free, locally-grown food.
Japan has more plant factories (PFs) than any other country. The largest number of plant factories are located in Okinawa Prefecture near Taiwan. The rapid commercialization and financial subsidization by the Japanese government of PFs, which began in 2010, are helping to drive interest in their development.
Another reason for the increase in PFs in Japan is that the country has been importing a large amount of fresh, sliced salad vegetables from China. The Japanese are concerned about the amount of pesticides being used for Chinese vegetable production and looking for alternative sources of fresh vegetables and herbs.
Hort Americas spoke with Dr. Toyoki Kozai, professor emeritus at Chiba University and chief director of Japan Plant Factory Association, about Japan’s expanding plant factory industry. Chiba University researchers are studying various aspects of indoor farming. A PF on the university campus, which is operated by a private company, is selling around 3,000 heads of lettuce daily to a variety of customers, including Japanese grocery store chain Tokyo Stores.
The number of Japanese plant factories producing more than 10,000 heads of lettuce daily is estimated to be around 10.Photos courtesy of Dr. Toyoki Kozai.
How large is the average plant factory in Japan and can you describe what type of equipment is used in one of these operations?
As of March 2014 there were about 170 plant factories (PFs) in Japan. Of these, 70 are producing more than 1,000 lettuce heads (50-100 grams per head) or other leafy greens daily. The number of PFs producing more than 10,000 heads of lettuce daily is estimated to be around 10.
The average floor area of a PF with 10-15 tiers for producing 10,000 lettuce heads daily is 1,500 square meters. The main components of a PF are:
A thermally well-insulated and airtight warehouse-like structure with no windows.
Tiers/shelves with a light source and culture beds.
A carbon dioxide supply unit.
Nutrient supply units.
An environment control unit.
Other equipment includes nutrient solution sterilization units, air circulation units and seeders.
Are most of Japan’s plant factories located in renovated buildings (i.e. old warehouses, abandoned factories, etc.) or are the buildings housing these operations constructed specifically for use as plant factories?
Sixty percent of the PFs in Japan are located in new buildings.
Why has Japan been one of the leaders in the development of plant factories?
Citizens’ concerns for and interest in health, pesticide-free products, freshness and high-tech are high. There are many researchers who have been doing research on PFs for more than 10 years. e Japanese government started subsidizing R&D and doing extension related to PFs in 2010.
Are most of the Japan’s plant factories operated by private companies and/or corporations or are there some operated as family farms?
Thirty percent of PFs are operated by families with ve to 15 part-time workers. Half of these PFs are for vegetable production. Ten percent of the PFs are operated by agricultural unions or similar organizations. The rest are operated by private companies.
What are the most common crops grown in the plant factories?
Primarily green leaf lettuce, romaine lettuce, frill lettuce, spinach, basil and arugula.
Are there any limits (i.e. space restrictions, plant size, light requirements, etc.) to the types of crops that can be grown in plant factories?
Plant height is 30-40 centimeters or less, grow well at a photosynthetic photon ux (PPF) of 150-250 micro-mol per meter squared per second (umol/ m2/s) and at high planting density. Plants can be harvested within two months after seeding and respond well to controlled environments.
How are most of the crops grown in plant factories marketed to consumers?
The produce is sold to diverse markets. Forty percent to large- and medium-size supermarkets, 30 percent to restaurant chain stores, 20 percent to meal delivery service companies and the rest to department stores, convenience stores and Internet shopping.
Is there any type of marketing on television, radio, online, newspaper, etc., done for the crops grown in the plant factories?
Most marketing is done on PF websites for ordering via the Internet. The PFs also do many interviews for articles and TV news without spending money for advertisement. PF sales personnel visit supermarkets, restaurants and department stores frequently.
In regards to the production system set ups currently being used in plant factories, where could the greatest improvements be made?
Automation for transplanting, harvesting, packing and cost and production management systems.
What are the benefits/advantages of plant factories over greenhouse production and traditional field crop production?
Ten- to 100-fold annual productivity per unit land area regardless of weather, clean and no need to wash before cooking and a long lifetime. Consumers are now interested in its nutrition for humans, taste, functional and medicinal components in leaves, beauty color and mouth feeling
Japan’s plant factories are used for the production of leafy greens, herbaceous medicinal plants, herbs and miniature root crops such as micro carrots and turnips.
What are the benefits/advantages of greenhouse production and traditional field crop production over plant factories?
PFs produce vegetables with high quality (small, delicate looking and flavorful) which cannot be produced in greenhouses or in the fields. The PF vegetables are 1/3 to 1/100 the size of greenhouse- or field-grown vegetables. PFs enable consumers living alone to eat fresh vegetables daily.
Do you think that plant factories will be able to overcome their current limitations to compete with greenhouse and field production? If so, how many years do you think it will take for the production costs to be comparable?
PFs are useful only for the production of leafy greens, herbaceous medicinal plants, herbs, and miniature root crops such as micro carrots and turnips. These root crops must have edible tasty leaves.
PF vegetables are not replacements for greenhouse- and field- grown vegetables. They are new products and create a new market. It will take about 10 years in Japan, less than 10 years in China.
What aspects of plant factory production are being studied at Chiba University?
The production of low potassium lettuce for persons who have kidney-related problems.
Development of production and cost management systems.
Lighting system using LEDs.
Reduction in electricity costs.
The physiological disorder of tip burn.
For more: Dr. Toyoki Kozai, Japan Plant Factory Association, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha, Kashiwa, Chiba, 277-0882, Japan; kozai@faculty. chiba-u.jp.
Additional articles on Japan’s plant factories are available at:
http://www.japan-acad.go.jp/en/publishing/pja_b/ contents/89/89_10.html; http://www.meti.go.jp/english/policy/ sme_chiiki/plantfactory/about.html
David Kuack is a freelance technical writer in Fort Worth, Texas; firstname.lastname@example.org.