Can You Grow Pesticide-Free?

Columns - Hort How-To

Use our quick test to find out.

Maryland’s call for applications for medical marijuana cultivation, processing and dispensary licenses received an overwhelming response with more than 1,000 applicants. Investors appear confident they can live with federal banking and IRS tax-deduction regulations. That leaves the future awardees to face the other major federal regulation hurdle: pesticides.

High-visibility, pesticide-related product recalls (such as the December 2015 recall of 35,000 ediPure edibles, and the recall of nearly 100,000 packages of Mountain High Suckers less than two weeks later) are exerting pressure on regulators and the industry to make good on the promise of clean cannabis.

Operations in jurisdictions where pesticides are allowed can build solid pest management plans on those pesticides and not be afraid of triggering hot test results. But in locales where pesticides are prohibited altogether, growers can still thrive free of pesticides.

This article was inspired by working with clients who are faced with having to do just that, as well as those who see value in being able to use “pesticide-free” as a market differentiator.

Here is a tool to help operators quickly assess whether pesticide-free growing is a viable choice, or to see where they need to make changes to reduce their pest-related risks.

Those changes may mean moving walls, adding AC or dehumidifiers and more. By pricing out these potential improvements, operators can make more informed decisions about how they want to face the challenge.

Working Without a Safety Net

Pesticides enabled other plants to be successfully grown under inhospitable conditions, and that greatly influenced many current mainstream horticultural practices and facility designs. If pests could be controlled by cheap pesticides, why spend a lot of money keeping pests out?

Traditional integrated pest management (IPM) was developed hand-in-hand with pesticides, a common element of most mainstream commercial IPM programs. Enter cannabis, with no available pesticides labeled as approved for use on the plant; those traditional IPM practices and designs will not meet the stringent demands of cannabis regulations.

For example, mainstream crops are able to withstand sizable pest infestations and still retain their marketability thanks to pesticides. In pesticide-free growing, instead of spraying once a pest population reaches a certain point, the grower is left either limiting the population or removing the plant if defenses are overwhelmed. Economic thresholds are much lower in cannabis than in traditional agriculture.

The stakes go up when the tightrope performer works without a net. By mainstream standards, pesticide-free growing is indeed working without a net.

Strategies for Pesticide-Free Grows

IPM for cannabis is firmly based on traditional IPM practices and modified to the particular demands of cannabis.

Traditional IPM allows pesticides, so the first modification is to drop pesticides from the toolkit. When we do that, the remaining tools are nicely outlined in the University of California at Davis’s definition of IPM (paraphrased by the authors):

Integrated pest management (IPM) is a strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices and use of resistant varieties.

At least two IPM strategies exist for using these tools. One is to use non-pesticide controls to attempt to co-exist with pests as is typical in mainstream IPM practice, or you can go the route of taking extreme exclusion measures to keep pests out altogether.

Allowing pests in an operation is possible as long as the grower has non-pesticide-based ways to control at least the most well-known and prevalent cannabis pests. Beware though, we’re still looking for an effective predator-based solution for root aphids, so reaching the point of total assurance that you can control everything is a challenge.

The exclusionary strategy places a maniacal focus on preventing pest entry. Existing facilities can be remediated based on feedback from this assessment. But the greatest advantage would come from using this assessment in developing an IPM strategy as input for new facility designs before construction contracts are signed.

Assessing Your Pesticide-Free Rating

Before getting to the assessment tool on page 90, here is some background on the questions used.

Pesticide-Free Assessment Test

Answer the following and tally your score.

  1. Physical Isolation

    • Field grown [ 0 points ]
    • 1 enclosure [ 1 point ]
    • 2 enclosures [ 2 points (building within a building) ]
  2. Environmental Isolation

    • If air in one space is freely mixed with air from other spaces or the outside [ 0 points ]
    • If each cultivation space has its own environmental control system [ 1 point ]
    • If you can prevent the entry of PM into a space [ 2 points ]
  3. Decontamination Procedures

    • If staff can enter a grow space in street clothes [ 0 points ]
    • If staff must put on overgarments before entering a cultivation space [ 1 point ]
    • If staff must decontaminate before entering the cultivation envelope [ 2 points ]
  4. Environmental System

    • If the environmental system has trouble with nominal conditions [ 0 points ]
    • If seasonal extremes challenge your environmental control system [ 1 point ]
    • If your system allows quick and accurate control of the environment across the seasons [ 2 points ]
  5. New Plant Isolation

    • If you do not isolate, inspect and treat new plant material [ 0 points ]
    • If you have isolation processes, but they have failed [ 1 point ]
    • If your processes ensure pests on new plant material will be found and removed [ 2 points ]
  6. Scouting

    • If none [ 0 points ]
    • If you have an established and active scouting program [ 2 points ]
  7. Cleanliness

    • If spaces are always occupied by plants [ 0 points ]
    • If flower spaces can be emptied and cleaned between crops [ 1 point ]
    • If all spaces can be emptied and cleaned between crops [ 2 points ]
  8. Microbial Growth

    • No strategy to prevent microbial growth in drying and cure rooms [ 0 points ]
    • Plan in place to prevent microbial growth in drying and cure rooms [ 1 point ]

Your Total Point Score:

Think of these scores as reflecting the risk a grower would take in moving to pesticide-free growing in the assessed facility.

A perfect score of 15 indicates that the design being assessed presents a relatively low risk for uncontrolled pest outbreaks. Existing facility operators can claim bonus points if they have been able to operate with no history of PM infection.

Scores between 10 and 14 indicate the design has a higher level of risk, but many of the building blocks are in place so the grower may be able to seriously consider growing pesticide free if they are willing to make some changes.

Scores between 5 and 10 may represent the need for significant remediation or redesign to create conditions favorable to pesticide-free growing.

Scores below 5 indicate that there would be a great deal of risk in trying to grow pesticide-free in the assessed facility unless steps are taken to address the shortcomings.

Important note:This assessment reflects the professional experience and opinion of the authors as to what constitutes a pesticide-free capable operation and is intended to get growers to think through key aspects of IPM practices under the extreme condition of no pesticide usage. The user accepts all responsibility in using the results of this assessment in making business decisions.

About the Authors: Kerrie and Kurt Badertscher are co-owners of OtokéHorticulture LLC (OtokeHort.com), and authors of  "Cannabis for Capitalists". They have worked with large-scale cannabis producers for more than 5 years. Kerrie has been involved with plants her entire lifetime and earned certification as a Professional Horticulturalist by the 100-year-old American Society for Horticulture Sciences. Kurt brings his 34 years of corporate experience and operations management skills to bear on the business challenges of cannabis cultivation.