Estimating optimal daily nitrate, potassium, and water requirements of Cannabis sativa ‘cherry wine’ during the vegetative phase

Abstract

Mineral nutrient requirements of Cannabis sativa ‘cherry wine’ (hemp) were studied under steady-state nutrition where nutrients and water (H2O) removed via transpiration uptake were replenished daily. Nitrate (NO3 −), potassium (K+), and H2O uptake for hemp are presented for 24 h periods over the course of vegetative growth. This can estimate the changes in potential NO3 − and K+ uptake rate in accordance with demand. Daily nutrient uptake and transpiration rates are discussed relative to the plant's H2O uptake and relative growth rate. Non-limiting conditions were achieved at base nutrient recipe NO3 − and K+ concentrations of 201 and 290 ppm. Biomass accumulation and stem caliper increment increase over the vegetative growth cycle were found to have a positive linear correlation with NO3 −, K+, and H2O uptake. Consequently, NO3 − and K+ concentrations in the irrigation solution can be steadily increased throughout the hemp vegetative cycle in relation to the driving relative variables growth and transpiration rate. In so doing, a time dimension is introduced concerning the nutrient amount supplied relative to plant biomass accumulation and nutrient uptake via the transpiration stream. Overall, lower amounts of NO3 − and K+ were needed to optimize plant growth than previously thought by industry professionals.