In a vertical farm, we can provide the plants we are growing with a climate very similar to the original climate they are designed to grow in. For example, spinach likes it cold, especially at the start of their growth cycle, and we can set up the climate to provide that. In contrast, basil likes it warm because it is a tropical plant. Some species grow best at a temperature of around 28 °C. Some plants like a long night’s sleep, while others grow well under a long day of illumination. Each crop has its own climate requirements and limits.
Creating the ideal climate doesn’t always mean selecting what’s good for the plant; sometimes it’s about what’s good for the consumer. For example, growing red oak lettuce in a climate and under LED grow light settings that are good for the plant’s development will not necessarily result in the deep red-colored lettuce that comes from growing it outside. In an open field, the red oak lettuce encounters various environmental changes that are interpreted as “stress factors,” like UV radiation or large temperature changes. These factors make the lettuce produce a protective pigment (anthocyanin) that gives the lettuce its red coloration.
This “stress” is neither good nor bad for the plant, it is just the way the plant is designed to survive through different climatic changes in nature. In this case, the plant’s coping mechanism is good for the consumer, who is used to seeing a red pigmented lettuce and would not accept a red oak variety of lettuce that is green, for instance. And it is supposed to be healthy, too.
In a vertical farm we can create the specific climate and lighting conditions that mimic the natural environment a crop is grown in to get the best results. In the case of the red oak lettuce, we can even simulate the environmental changes it undergoes to trigger the plant to produce the characteristic photo protective pigments it is known for.