Mar 4, 2021
Study Looks At Phosphorus Nutrition Of Greenhouse Grown Hemp

A team of hemp researchers at North Carolina State University has published a study on nutrition of greenhouse hemp, focusing on phosphorus fertilization.

Limited research exists on the fertility requirements for industrial hemp (Cannabis sativa) and the impact of fertility on plant growth and cannabinoids. Optimizing floral production for cannabinoid production and especially cannabidiol (CBD) production, is an economic goal for growers.

Phosphorus (P) is an essential nutrient for plant growth and plays many key roles in plant growth and when deficient leads to suboptimal plant growth. Grower P fertility rate recommendations vary greatly, with suggestions of up to 196 mg·L⁻¹ P over part of the production cycle. Four P fertility rates (15, 60, 120, and 180 mg·L⁻¹ P) were evaluated to determine the optimal fertility for C. sativa on a high CBD-type cultivar ‘BaOx’.

Plant height, diameter, and total biomass were similar across all examined P fertility rates. Foliar P concentrations increased linearly, with the greatest P accumulation occurring in plants that received the highest fertility rate of 180 mg·L⁻¹ P.

Given no differences in biomass production were found, and the luxury uptake of P as fertilization rates increased, the results indicate that rates above 15 mg·L⁻¹ P are not beneficial for plant growth and only add economic cost to the grower and potentially cause waste and pollution to the environment.

The team is lead by the Department of Horticultural Sciences’ Dr. Brian Whipker and the paper’s lead author is Patrick Veazie, a junior at NC State. To read the full paper, visit

Source: North Carolina State University

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