There is a very popular opinion that the taste of vegetables is formed on the basis of the genetic characteristics of the plant variety and cannot be improved by artificial methods. This would be true if the other growing parameters were normalized. However, this rarely happens in greenhouse vegetable farms.
For example, the Finnish company Valoya initiated a study, and our manufacturer of city farms and phytolamps GoodGrow translated it into . In their experiment, the Finns compared the taste and other qualities (smell, color, appearance, solid mass density) of a pair of traditional crops (tomatoes, lettuce, arugula and basil) grown under different artificial lighting. The study used different spectra and types of lighting, but we will focus on two – these are HPS (arc sodium lamps) and LED AP673L (Blue – 12%, Green – 19%, Red – 61%, Far Red – 8%).
This study examined the post-harvest ripening of tomatoes under various light treatments. Raw tomatoes turned red with any light treatment, but the highest redness (lycopene content) was achieved with far red coated LEDs.
The best color was obtained with a higher ratio of red to far red in the spectrum (phytolamps AP673L). In addition, tomato firmness was higher using the above spectrum. The same spectrum showed an increase in the antioxidant content of basil, which protects the plant itself from fungal pathogens such as powdery mildew. All this can be considered as an improvement in quality caused by the right choice of spectrum.
During in-house testing at Valoya’s factories, many interesting observations have been made about other quality improvements brought about by different spectra, such as AP673L. For example, the shelf life of lettuce is increased due to the higher dry matter content of leafy greens. When the plant has more fiber and less water, food stays fresh longer because it takes longer to dry.
The total amount of phenols is associated with the taste and smell of the vegetable, and it also increases with a finely balanced light spectrum. The taste of vegetables is, of course, harder to measure, since everyone’s tastes are different, but this was also done in Valoya’s internal trials, where flavor scores were given in a blind test. All results showed that photobiological light not only increased yields, but also improved the quality and taste of vegetables.