If you are trying to increase THC production or trichome production you are best served IMHO by increasing UVb to your plants. This is the light wavelength associated with trichome productions in plants. Here is some input but if you google or other search engine on this subject there are many studies that have been done on this subject.
Ultraviolet lightis a wavelength of the light spectrum that is shorter than that of visiblelight. UV is on the far end of the violet part of the color spectrum, hence thename ultraviolet. Although humans are unable to see UV light we are aware ofits existence and its effects. Sunburn is the most common result of UV lightdirectly effecting humans, and once you’ve had a good sunburn there is no needfor additional convincing that the rays are real. To block this harmfulelectromagnetic radiation, we put on sunscreen or find a way to shade ourselveson sunny days. Medical marijuana plant’s process the different types of UVlight in different ways, including producing their own sort of sunscreen intrichomes. Let's examine the different types of UV light and their directeffects on plants.
UV-A is the long wave UV light—most commonly seen in ablack-light. Its primary effect on plant growth comes at a hormonal level. Thiswavelength will eliminate or limit certain hormones within the plant, effectingthe plant’s growth. Over millions of years, plants have created a synergisticrelationship with their hormones and UV light. UV-A wavelengths can effect thestructural growth in plants due to the hormones it helps to regulate.
UV-B light is the medium UV wavelength. This wavelength willeffect trichome production in medical marijuana the most. A medical marijuanaplant will create trichomes to protect itself from the would-be harmful rays ofUV-B.
Trichomes are mostly made up of water, which acts as an absorber of the UV-Bradiation. It also contains the majority of cannabinoids, found in a medicalmarijuana plant, including THC, CBN and CBD. In other words, the more trichomesa plant produces, the more cannabinoids (medicine) in the plant.
Many gardeners add UV-B specific bulbs to their indoor gardens to maximizetrichome production. You can purchase UV-B bulbs at any pet shop where they areused for keeping reptiles. Another way to ensure your indoor garden has enoughUV-B is to use metal halide bulbs in your blooming room because they naturallyhave a higher UV light output than high pressure sodium bulbs.
UV-C is the short wave UV wavelength. This frequency can causeadverse effects on plant growth. Receiving an abundance of UV-C light willcause severe radiation poisoning resulting in deformed growth, color loss oreven death.
As biological creatures are concerned, UV light can be good or bad. I believemoderation is key when supplementing UV light in your indoor garden. If youwant to add UV-B specific bulbs, I recommend supplying around 1/10th of thewattage in your garden. For example, if you have a 1000 watt flowering room,add 100 watts of UV-B. Another rule of thumb is to run 1/3rd of your bloomingwatts in metal halide. For example, in a 3000 watt bloom room, have 1000 wattsmetal halide and the remaining 2000 watts high pressure sodium. By addingadditional UV-B light,t you should see an increase in essential oil productionand, in turn, an increase in potency of your medical marijuana.
Not my writing and the author I don't have their name but this goes along with many other studies.