Lighting, Pesticides & the Future of Cannabis Cultivation: Q&A With Rx Green Solutions’ Head Grower

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By Becky Olson

Jonathan Nielson is a Colorado native with nearly a decade of cultivation experience in the legal marijuana industry.

Now, he’s the master grower for Rx Green Solutions’ cannabis research and development facility in Denver, where he leads a team focused on the science of nutrients used in marijuana cultivation.

Rx Green Solutions grows cannabis specifically for a Denver medical and recreational cannabis shop. Before moving its cannabis to the store, the company conducts scientific trials designed to pinpoint an ideal nutrient mix and regimen in a bid to figure out how to increase yields and improve flower quality and safety.

Nielson sat down with Marijuana Business Daily in September to talk about his research, scaling a marijuana grow and the future of cannabis cultivation.

One of the hot topics in cultivation right now is how various lighting technologies can improve quality and yields while also reducing energy requirements. What lighting technology does Rx use and why?

We use double-ended lighting technology because it gives you a larger square footage of light for the same amount of power. The bulbs ignite from both sides, as opposed to single-ended lighting that you screw in on one side.

The industry has discovered different spectrums will do different things for the plant, so what this allows us to do is put different bulbs in there for different light spectrums.

Use of pesticides is another contentious topic in the industry today – what’s your perspective on pest management?

The key to pest management is to be proactive. We find that if you have to react to a pest problem – whether it’s fungus, powdery mildew, etc. –you’re on the back side of a very difficult situation to manage. You’ve got to get ahead of it by anticipating the worst, but hoping for the best.

All of the pesticides we use fall under the 25b class (minimal risk) of federally exempt substances. We use an integrated pest management system where we spray twice a week with different types of ingredients.

You have to rotate your regimes, put them in combination, make cocktails. If you use the same thing all the time, pests develop resistance. But when you use an integrated system, it significantly lessens the chance of that happening.

What are some of the top challenges for today’s commercial marijuana cultivators?

One of the things we’re very conscious of is the word “simplistic.” It’s one thing for a home cultivator or small cultivator to manage multiple (nutrient) products, but with large-scale operations, you have to keep it simple.

You have a lot of people coming in and out of those facilities, and they bring (pathogens) with them – how do you keep a sanitary environment?

Another challenge is maintaining efficiency. The prices keep going down, but the costs of production stay the same. Simplicity is key.

What advice do you have for cultivators who are scaling up from smaller cultivation sites to large/commercial ones?

You want to take small steps. You don’t want to change a bunch of things all at once or you won’t know what worked and what didn’t work.

Do slow trials, test things out – you’ve got to be looking ahead at what’s coming in the industry too.

Speaking of the future of the industry, what are some of the things you are preparing for and what trends do you predict will play out?

I do think that LED lighting in the next few years is really going to start getting up and going. Irrigation is also something that is almost new to the cannabis industry in a certain way.  I think you’re going to see more companies adopting use of dosatrons (automatic fertilizing technology) in the near future.

I hope to see more regulations come down the pipe, especially with regard to consumer safety. There’s all kinds of regulations for growing food, tobacco – we barely have any in the cannabis industry.

Becky Olson can be reach at