Terpenes are major components of cannabis resin, just as they make up the largest percentage of aromatic essential oils contained in most plants. The scent of most flowers, herbs and spices are composed of these oils. When therapists use plant oils in aromatherapy, or when you use natural incense, perfume, or other scent to set the mood, you are inhaling various combinations of terpenes. They have the power to take you up or down, help you relax or focus, feel anxious or satisfied.
You recognize the presence of terpenes when you pinch that bud and take a whiff. Grapefruit, Silver Haze, Blueberry, Real Skunk—each of these odors brings a recognition of the type of high that the sample will explode into your brain.
As it matures sexually, marijuana produces terpenes in the glands that surround the flowers. Terpene levels increase during the dark period and reach their peak just before dawn. During the day they evaporate and fill the surrounding air with odor to warn predators. By the end of the day, at dusk, terpene (and cannabinoid) levels are at their lowest.