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Home > Articles > Cultivation > Content Piece

Would You Rather: Outdoor or Indoor Cannabis Cultivation?

By Roxanne Newman

Published: Sep 16, 2019   
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“Licensing is one of the biggest challenges cultivators in Europe are currently facing,” says Dr Callie Seaman, the avid director at Aqualabs Ltd, a nutrient manufacturing company.

Giving a rare insight into her cultivation expertise, Seaman will be a speaker at the Analytical Cannabis Expo Europe 2019, which will take place in London, UK on the 12th of November. In anticipation of the event, Analytical Cannabis caught up with Callie to discuss difficulties in European cultivation regulations and licensing, outdoor versus indoor growing, and the often-overlooked microbial pathogens in soil. 

European regulations, licensing and testing

Hemp. High THC. Research or extraction. Potential cultivators need to evaluate which of these licenses they require, yet this doesn’t seem to be an easy task.

“I think cultivation regulations and licensing within Europe is a very, very grey area and a lot of people don’t fully understand what criteria is required and the differences between a hemp license, a high THC cannabis license or an extraction license,” says Seaman.

In the UK, a hemp license is intended for industrial purposes, such as paper or bioethanol production, so can only let a licensee grow, not extract, their crops. Fortunately for Seaman and her colleagues, a THC license is also available for research purposes, but no supply is permitted.

“In order to be able to get a supply licence, you need to meet the MHRA guidelines and be what is known as EU GMP compliant. Ultimately, you must meet these standards to be able to make a product that can then be produced into a medicine,” Seaman explains.

“One of the biggest barriers is actually being able to get a license which allows you to grow enough to be able to produce product and not have sanctions on it. I think more needs to be done to spread that knowledge, definitely.”

But before any cultivation license can be issued, soil testing will usually be completed to ensure crop health and growth. But according to Seaman, soil testing within the UK also seems to be rather restricted.

“Most feedback that I hear regarding soil testing is that the cost is prohibitive. People don't want to have soil tested, because they are finding it’s £500 to have a test done and there can be changes between batches,” she explains. “I think there needs to be more availability of the laboratories, so that soil testing can be done for everyone.”

Outdoor versus indoor cultivation

As a researcher, Seaman favours rockwool and hydroponics. However, she has vast expertise in all mediums, as well as both outdoor and indoor growing.

“You never get the same plant growth results indoors as you do with the natural sunlight outdoors. Outdoor growth is phenomenal, but you are not in control,” she says.

But outdoor growing comes with outdoor problems. “Some years, you'll find that there is a lot of light, and you get really bumper crops, and you get a lot more change in secondary metabolites, for example, THC being converted to CBN,” Seaman adds. 

“Now indoors, you’re in more control of that environment, you’ve got less chance of crop failure, because you are optimizing temperature, water, and ensuring the same amount of light every single day. Ultimately, you can optimize and get the best photosynthetic rate.”

Although indoor growing has its advantages, a major drawback is that power consumption is vastly increased.

“With outdoor growing, heavy rainfall can run-off into local streams and other places. Also, outdoor growing impacts things like bees. Indoor growing, removes all these environmental impacts by reducing the risk of pollution around,” Seaman explains.

“However, indoors you have to use artificial light. Even though artificial light is improving, it is still not the same as that big red ball that's in the sky, producing free natural light. Ideally, I would like to see subsidies for renewable energy, for example, solar panels, wind farms, and anything that is recycling the energy.”

Outdoor growing is also subjected to an increase in pathogenic microbes, which are essentially out of the cultivator’s control and can present serious issues, not just for the health of the plant but also for humans.

“Everybody understands about pesticides and the danger of pesticides. Everybody understands heavy metals. This is really kind of rammed down everybody's throat. But what is missed a lot of the time is all these other pathogens that we’re out of control of.”

This is especially the case for soil-based cultivation, which can be both indoors and outdoors. However, growing outdoors also increasing certain factors, such as pesticide blow-over and habitable insects.

“I look at soil as a little bit of a hotel for any insects,” Seaman says. “Like fungus gnats, they really like anything that's warm and has organic matter. At the beginning of their life cycle they've got nematodes, which are little worms that will wiggle about in the larvae within the root zone. Now they can spread disease to the plant and travel from plant to plant.”

With significant advantages on indoor growing but added costs, the cultivation choice can be difficult to make as well as procuring the appropriate license.

“Ultimately, if you're trying to produce a medicine, I would say indoors. If you're producing for wellbeing, where you are not immunosuppressed, outdoors is not going to be such a problem. It is also dependent on your license, which dictates what you can actually cultivate, for example, strains which are low in THC for a hemp license,” Seaman says.

“Education for cultivation regulations, licensing, and testing is needed. However, we still have so much to learn on this subject.”

Callie Seaman will present at Analytical Cannabis’ 2019 Europe Expo on the 12th of November at the Radisson Blu Edwardian Heathrow Hotel, London, UK. You can register here to attend.

Roxanne Newman

Team Lead, Conference Production

Roxanne joined Analytical Cannabis in 2019 as conference producer, where she helps to organize our webinars, online symposia, and physical events in Europe and the US. She graduated from Anglia Ruskin University in 2019 with a 1st class Bachelor's in Biomedical Science and was also awarded the Undergraduate Prize for Physiology from the Physiological Society, London. During her studies, Roxanne also received a prestigious summer research studentship to investigate the effect of natural products on the gut epithelial.


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