Horticulture

On-Site Fertility Management: Ecological Systems Design for the Cannabis Farm

Written by Shawn Tucker

There are various ways to set up ecological systems for cannabis farmers. The first decision is whether to grow in soil, hydroponically, or aeroponically. These systems have their advantages and disadvantages; however, this key decision will impact future decisions about cannabis cultivation.

Another key factor to help decide how to set up systems is what the point of growing is. When it comes to cannabis, there are a number of purposes for growth. Cannabis can be grown for industrial use or for supplemental/medical/health and wellness use. The methodologies used to grow cannabis will vary based on what it is being harvested for.

There are various options available to cannabis farmers to automate specific aspects of the growing process. Automating irrigation systems and nutrient delivery can reduce labor costs and margins of error. Considering drip irrigation and injection style fertilization are two examples of automation to consider when setting up ecological systems on a cannabis farm.

 

Fertilization/Nutrient Considerations

When it comes to fertilizer/nutrient delivery especially, eliminating errors is key. Maintaining the proper nutrient balance is vital to the health of the plant as it moves through vegetation and flowering. Cannabis is a moderate feeder.

The primary nutrient discussed for fertility is nitrogen. According to Tami Van Gaal, “A constant feed rate of 100-ppm nitrogen will serve nearly all [cultivars] early in the vegetative phase. Later in vegetation, raise rates to 150-ppm nitrogen. As plant demands continue to increase, 200-ppm nitrogen will generally meet the crop needs at peak flower. From there, rates can be lowered back to 150-ppm nitrogen for a few weeks prior to pre-harvest treatments.”

A 2021 study focused on nutrient impact for the quality of fiber and biomass from industrial hemp and not on the cannabinoid or phytochemical impacts. [1] Future studies are needed to establish how nutrient usage and fertilization practices impact cannabinoid content in addition to any consequences on terpene profiles or concentration.

Primary nutrient levels that have been studied are nitrogen, potassium, and phosphorus, with the majority of the work having been done on nitrogen. Additional nutrients include: calcium, magnesium, and sulfur. [1] Some studies have been done on the impacts to seed production and the protein levels of the seeds as they are being harvested as a food product and a plant-based protein option.

 

Reference:

[1] Wylie SE, Ristvey A, Fiorellino N. Fertility management for industrial hemp production: Current knowledge and future research needs. GCB-Bioenergy. 2021;13(4):517-524. [journal impact factor=4.745; times cited = 3]

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Shawn Tucker

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