How to Grow Chemistry (Motorbreath 15 x Headbanger)

Departments - Upfront | Breeder’s Brief

Cannabis cultivation information for growers, from breeders.

Photo by Sjoerd Broeks

Cultivar Details:

Plant physiology: Chemistry has two basic phenotypes when grown from seed. There also are more subtle variations within those two types. The Motorbreath 15 (MB15)-dominant plants stay squat and grow similarly to the MB15 parent. Chemistry has greasy, San Fernando Valley (SFV) OG/Chemdog-like buds that hold together better during trimming than the SFV OG. The Headbanger OG-dominant plants stretch a little more in flower and produce larger, longer, more open flowers.

Average yield: Yields vary depending on grow conditions and phenotype selection. Chemistry sits in the upper-middle category yield-wise. I regularly harvest 55 to 60 grams per square foot with the Chemistry cultivar, making it a solid addition to the family.

Flowering time: 60 to 63 days.

Ideal light-intensity setting: During trials, we found that Chemistry can handle high light levels and that the plants hold up well during the flowering stages, where they are pushed a little more toward generative growth.

Ideal environment temperature: Chemistry is a fairly resilient variety. Like most Cannabis plants, this cultivar enjoys a stable climate with small differentials between days and nights. Warmer temperatures and higher humidity during onset to flower stage and cooler temps, slightly lower light levels and a drier, crisper climate in the last two weeks showed the best results with the highest overall terpene content.

Ideal cultivation environment-relative humidity: Chemistry has proven to be vigorous and resistant during trials; however, like all Cannabis varieties, there is a risk of pathogenic infection within the flowers if climate is allowed to drift outside of the parameters set by the grower. Chemistry tends to be more resilient than her SFV OG grandparents and will thrive in most climates. Generally, we run plants at 60% to 70% RH during the nursery and vegetative growth stage and gradually reduce RH percentage and temperatures during flower.

Water needs: Chemistry tends to grow fairly fast with a good, lush canopy. It is fairly resilient to dry downs and generative steering for an OG-dominant plant, which makes it a good production plant. Water use by crops is measured by calculating the leaf area index (LAI) of the crop (the total leaf area per meter squared) and the action of the climate around the crop (light levels and temperature). Varieties handle these inputs very differently, so we run any OG Kush-dominant plants on a gentle program during the first trials from seed and then push a little harder on rounds two and three to see where the sweet spot is per selection.

Nutrient needs: Average needs and fairly forgiving. Grow Chemistry like you would an OG (less pruning, tighter spacing, more aggressive dry downs in substrate early on during root set) and you can’t go wrong.

Cannabinoid profile: High THC 20% to 24%

Terpene profile: Chemistry has a nice blend of Sour Diesel and OG. Odor profiles vary between fuel, earth and citrus.

Susceptibility to any diseases/conditions: Chemistry is resistant to pests and disease.

Sjoerd Broeks is the genetic development and R&D director for The Pharm LLC, a cannabis cultivation business in Willcox, Ariz.