Green healthy leaves are always a great sign
Unfortunately, they don’t all match (for example some growers say to harvest in the morning, while others believe you get more THC if you harvest during the plant’s dark period), but these are the most common flushing techniques that I’ve heard to increase THC levels right before harvest.
Learn more about when to harvest cannabis (with lots more pics!) Get the effects you’re looking for.
These Mandarin Cookies buds were listed as producing 25% THC. They and produced about that under HID grow lights but tested at 27% THC under the HLG 300. Several other clones from the grow also tested at higher THC than expected. This was only one grow comparison but so far the HLG seems to be the most “THC-increasing” grow light I’ve tried.
I don’t think anyone has yet discovered the “perfect spectrum” but some LEDs are certainly getting better bud quality than others.
“Because of the federal strictures, there weren’t any standardized methods. Labs had to validate everything themselves,” Brauninger says. “It’s difficult to bring in expertise when there isn’t a wealth of information available, and no trade association to help share techniques.”
“For a product to be sold in most US states, it has to be tested externally,” says Jahan Marcu, director of experimental pharmacology and behavioral research at the International Research Center on Cannabis and Mental Health in New York City.
A student inspects a cannabis plant at Niagara College Canada’s teaching laboratory in Niagara-on-the-Lake, Canada. Credit: Niagara College
A2LA is also helping labs to attain ISO/IEC 17025 accreditation, the main international standard for testing and calibration labs. It covers all phases of lab operation, including staff training, data protection and dealing with conflicts of interest.
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Besides the challenges of growing a sufficient amount of high-quality cannabis for a rapidly growing market, cannabis companies have to deal with something that illegal growers do not — government regulation.
“As the industry has gotten bigger, they realized they must transition to use modern horticultural science,” says Youbin Zheng, a horticulture researcher at the University of Guelph, Canada, who works with cannabis companies.
Such labs are beginning to adopt standardized tests for potency and purity using gas chromatography and high-performance liquid chromatography. They are also developing methods to identify and measure levels of THC and other cannabinoids, as well as contaminants such as heavy metals and pesticide residues. “These aren’t necessarily new tests that have been created for this industry, but the type that had to be applied for this product,” says Brauninger.