Growing without synthetic pesticides: Q&A with Fleurish Farms’ Ethan Rubendall

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By John Schroyer

Grower Ethan Rubendall is arguably an extremist: He refuses to use chemicals on his cannabis plants, opting instead for all-natural techniques to fight pests.

He argues his approach – including the use of plant-based sprays and aphid-repelling crops like chickpeas – is more effective than the potentially toxic chemicals other MJ growers use.

Rubendall has been growing cannabis professionally for about three years, most of those as the head of plant nutrition at California’s Fleurish Farms. During that time, he’s developed his own approach to pest management, which has blossomed into a hot-button issue among cultivators and activists over the past year. Synthetic pesticides have made headlines for causing product recalls in Colorado and new regulations in several more states.

“I’ve never used any kind of synthetic pesticide,” Rubendall said. “And it’s worked wonders.”

Marijuana Business Daily asked him to discuss his approach to fighting pests and protecting his plants.

Does Fleurish Farms have a policy on pesticides as far as what you use or don’t use?

We don’t use any kind of synthetic pesticides. Our (integrated pest management) program is simply natural. It’s either herbs or botanicals that we procure from farmer’s markets, or it’s all grown on the property.

Why is that?

Systemic pesticides, like Eagle 20, stay in the plant. I don’t specifically recall the half-life, but it’s not a short period of time whatsoever. Even when people talk about using it on a clone, that’s still going to be in the plant through the flowering cycle, while you harvest it, after you flush it. And it’s going to the patient. So for us, if you want to call what you’re giving out “medicine,” then it has to be grown organically. And what better way to do that than with other herbs?

Do you think pesticide regulations – like those enacted in Colorado, Oregon and Washington – are a trend that other cultivators are going to have to deal with at some point?

From what I’ve seen, I think it will. It’s already becoming more common in other industries. Even some of these biodynamic lines are coming back with (pesticides in them), just from overspraying and having used them everywhere. So I think that trend is going to continue full speed ahead. They’re not to be used as preventative measures. There’s really no reason to – even as a last resort. I’ve seen, firsthand, mites and pests that the grower can’t do anything about with whatever they’re using.

But you can beat ‘em using the proper (integrated pest management program) and predatory insects. I’ve seen those chemicals fail where a rigorous natural IPM program has worked. When you’re looking at it that way, there’s no reasons those regulations shouldn’t be in place or work.

Tell me more about the IPM program you use at Fleurish.

Right now we’re putting together a cover crop, like sweet peas and chickpeas, which repel aphids. We also grow onions, garlic, organic ginger, and we use cinnamon – the sweeter variety – and all of these things are antibacterial, antifungal. They control the types of life in our garden, and they promote the healthy life to flourish and all the bad stuff to die.

So along with cannabis, you’re growing onions, garlic, organic ginger, and all these other things right next to cannabis plants outdoors?

We use a cover crop.

What’s a cover crop?

That’s like clover. It fixes nitrogen in the soil, and promotes things like chickpeas that repel aphids. And that kind of controls your bottom layer, to keep things from crawling up there. In separate areas of the farm we’re growing vegetables like onions and garlic. And we turn those into a probiotic spray through fermentation, and (integrate them) into our pest management program. So we only spray things that are made out of plants, and it keeps the bugs away. There’s no reason to use anything else.

As far as pesticides like Eagle 20, is that still a really widespread problem? Do a lot of growers still use pesticides like those?

I definitely have seen it. You can just look at lab reports on the internet and see how many are failing for pesticides, or failing for mold or things like that. Because of the regulations coming down, the training to use organic methods isn’t there. So people don’t know how not to use pesticides. And even if they’re not using pesticides, their medicine isn’t medicine because it’s got mold and it’s got bugs.

I’ve never used any kind of synthetic pesticide. It’s always been organic: rosemary oil, thyme oil, neem oil, ginger, garlic. And it’s worked wonders. It’s kind of amazing what you don’t need.

A lot of people in the cannabis industry see pesticides and pest management as a really serious problem. What do you think the solution is going to be for the industry?

Regulation really only comes from inadequate education. People just need to understand how easy it is to grow with these methods. Most simply don’t know how to use pesticides. And to protect their profit they’re going to use (pesticides) every time. To keep a roof over your head, you’re going to use them every time. To keep your kids in school, to pay your light bill, and that’s the only way they know. So education is essential.

This interview has been edited for length and clarity.

John Schroyer can be reached at