UV light and THC (Tetrahydrocannabinol). The UV light is a spectrum of colors that we cannot see. We cannot but plants do. The UV has three different types according to the wave length.
These wave lengths are classified in nanometers. The UVA goes from 320 – 400 nm. The UVB goes from 280 – 320 nm and finally the UVC goes from 10 – 280nm. Remember they are colors that human beings cannot see.
Atmosphere has filters that help to retain these colors. Otherwise life would be impossible for human kind. Plants that live outside receive certain percentage of this light. Normally a ratio between 5% UVB and 95% UVA. They have evolved for thousands of years to be able to survive. Cannabis developed THC in order to protect the next generation of plants. The more UV the plant receives the more THC will produce. UV means stress and this causes more quantity of THC.
That is why sativa have more levels of THC. This is because the amounts of UV radiation in the tropics are higher. And it also occurs in high mountains. When we grow cannabis indoor or in green houses, we protect the plants from many problems like bugs, viruses, diseases and so on. The plants grow more and produce more. However the high pressure sodium lights have zero UV light and because of this their potential is far below it should. This occurs because the environment is too perfect. And stress and THC are related.
Curiously, the good lamps have UV radiation. And they cost the same than bad ones; those unable to produce UV light. It is important to understand how the cannabis plants work. Cannabis plants are always doing something. They never stop. They are growing, moving nutrients, developing leaves, buds and so. If you introduce the proper UV spectrum to the plants, you will force them to protect themselves and this means an increase in THC.
Using proper UV is very cheap and you will increase about a 20% your levels of THC. The key is giving the plants as much or more UV, in the right spectrum, than they would get if they were outdoors. You have to give them as much as possible without being damaged.
Using good lamps is as important as using good soil, nutrients and so on. And don’t forget a good lamp costs almost the same than bad ones. Check in internet what types of lamps have correct UV spectrum and go for them. You will be rewarded.