The role of LED lighting in gardening
The use of LEDs in fruit and vegetable farming is mainly to prolong the growing season, especially in the colder regions of the summer. In the past, artificial lighting used for plant growth was mainly high pressure sodium lamps (HPS). However, a clear advantage of solid-state lighting based on LEDs is that lighting does not generate heat, and growers can use interactive lighting, which means that light is placed in the middle or side of a plant, and the light is exposed to the lower part of the plant in a vertical or horizontal direction.
However, the biggest impact of LEDs is on growing leafy vegetables and herbs, which can only grow to a height measured in inches and grow on shelves, each shelf with a dedicated set of LED lamps near plants. This layered shelf is common in so-called urban or vertical farms, where they occupy relatively small growth space in buildings near the population center, while the best lighting and technology, including hydroponic cultivation, can be shorter than outdoor growth cycles.
Gardening lighting Challenges
Of course, there are challenges to any emerging technology, and there are also challenges with respect to led gardening lighting. At present, solid-state lighting technology is still very shallow experience, even many years of gardening scientists are still working on the plant's "light formula", the current new "formula" some of them are not feasible.
Rami Vardi, general manager of Canoga Park Lighting Manufacturing Co., said that the market for lighting manufacturers in Asia is usually affordable but low-end, with many low-end products in the market lacking relevant certifications such as UL ratings, and LM-79 and LM-80 led reports. Vardi said many growers tried to deploy LED lighting early, but because of poor performance and frustration, high pressure sodium lamps remain the industry's gold standard.
Of course, there are many high quality lighting products in the market, including Philips, Osram and Hubble lighting. Osram and Philips spent years working with university and specialized research groups to conduct horticultural research.
However, horticultural and floral growers still need better metrics related to application. For example, the agricultural Lighting Board of the American Society of Agriculture and Biological Engineers (ASABE) began developing standardized metrics in 2015. The work is considering metrics related to par (photosynthetic effective radiation) spectrum. Par ranges are usually defined as 400-700 NM spectral bands, wherein photons drive photosynthesis actively. Common measurements related to par include photosynthetic photon flux (PPF) and photosynthetic photon flux density (PPFD).