., 2017 ). Leafy greens, such as lettuce, are among the group of popular crops for indoor farming ( Kozai, 2013 ). Crops are produced using electric lighting for an average of 16 h·d −1 ( Agrilyst, 2017 ) in indoor farms. Thus, electrical energy-use costs
, to improve the energy use efficiency in PFALs, it is necessary to find the optimal light environment for plant growth ( Kozai et al., 2016 ). Therefore, to investigate the optimal combination of light wavelengths for lettuce ( Lactuca sativa cv
Light is one of the limiting factors for plant growth. To increase the PPF for plant growth, greenhouse growers must supplement solar light with electric-powered light. The most common lighting technology used to increase PPF in the greenhouse
, alone or with blue LEDs, red LEDs, or both ( Park and Runkle, 2018 ; Yan et al., 2019 ). The world’s first white LED was created in 1996 as a phosphor coating used by blue LED ( Bourget, 2008 ) and the present white LEDs showed increased energy
alternative to using removable adhesive stickers with produce data is implanting the alphanumeric code directly on the produce surface. This can be accomplished using a newly designed laser etching device for labeling produce surfaces. The new device uses a
The North American greenhouse industry has come under considerable financial stress in the past decade, with numerous firms leaving the industry. The main reason often given was the increased energy costs. Some growers of greenhouse crops have gone out of business because of energy costs. Recently energy costs have stabilized; this change, accompanied with higher returns for domestically grown greenhouse crops, has decreased the growers’ concerns about the energy situation. We would be naive to think that energy costs will not rise again in the future.
Energy is like the air that we breathe, something that we have taken for granted for far too long. Almost every decade we have seen increased, almost insatiable, demands for more energy with little concern for supply or price. In the past decade, a grave threat to our national security as a result of our extensive dependence on unstable foreign oil supplies and escalating energy costs sobered up our energy thinking.
greenhouse uses solar energy as the sole light and heat source for winter crop production ( Figs. 1C and 2, A and B ) and is unique to northern China. These greenhouses are used to produce warm season crops such as tomato ( Solanum lycopersicum ) and
is high can help reduce energy use. However, the impact on plant development rate of altering the greenhouse temperature must be considered. Plant development rate in response to temperature is species specific, and it is linear between a base
floriculture crops, a −DIF is sometimes used by greenhouse growers to control height ( Myster and Moe, 1995 ). In temperate climates, high-energy inputs can be required to maintain a desirable greenhouse temperature, making fuel for heating one of the largest