Nitrogen, Veg Cycle.
Response of Medical Cannabis to Nitrogen Supply Under Long Photoperiod (2020)
Avia Saloner and Nirit Bernstein
“The plants were then divided into five treatments of N supply: 30, 80, 160, 240, and 320 ppm N,
five plants per treatment, and grown for an additional 32 days under 18/6 h light/dark photoperiod. Light
was supplied by Metal Halide bulbs (400 μmol m2 s1; Solis Tek Inc, Carson, California).
“N was supplied in the concentrations of 2.1, 5.7, 11.4, 17.1, and 22.9 mM (millimolar) [e.g., 30,
80, 160, 240, and 320 mgL-1 (ppm), respectively], 80% in the form of N-NO3- and 20% as N-NH4+.
“We report that the morpho-physiological function under long photoperiod in medical cannabis is
optimal at 160 mg L N supply. The plants demonstrated sensitivity to
high N supply, and supply above 160 mg L, was found to be
excessive, restricting growth and biomass deposition. Optimal plant
growth and development were obtained under 160 mg L N supply.”
Vegetative Growth
N - 160 mg L
Phosphorous, Veg Cycle.
Response of medical cannabis genotypes to P supply under long photoperiod:
Functional phenotyping and the ionome (2021)
Sivan Shiponi and Nirit Bernstein
“The plants were grown 30 days under increasing P
treatments of 5, 15, 30, 60, 90 mg L-1 in controlled growing
rooms under long photoperiod (18/6 h light/dark), 25 ◦C,
and irradiated with Metal halide bulbs (400 μmol m2 s1;
Solis Tek Inc, Carson, California; 25.9 mol m2 d1). Carbon
dioxide concentration was ~400 ppm.
“Our results suggest a wide optimum range for P in
medicinal cannabis at the vegetative growth stage, with a
minimum requirement of 15 mg L P and a recommended
application of 30 mg L. Biomass accumulation into leaves,
stems and roots increased with the elevation of P supply up
to the concentration of 30 mg L P and was unaffected by
further increase.”
Vegetative growth
P - 30 mg L
Potassium, Veg Cycle.
Response of Medical Cannabis
Genotypes to K Supply Under Long Photoperiod (2019)
Avia Saloner, Mollie M. Sacks and Nirit Bernstein
“The plants were exposed to five levels of K (15, 60, 100, 175, and 240 ppm K). The plants were
then divided into five increasing treatments of K supply; 15, 60, 100, 175, and 240 ppm, and grown
for 30 days under 18/6 h light/dark photoperiod using Metal Halide bulbs (400 μmol m2 s1, Solis Tek Inc, Carson, California).
“Growth response to K inputs varied between genotypes, revealing genetic differences
within the Cannabis sativa species to mineral nutrition. The concentration of the two major cation
nutrients, Ca and Mg, tended to decrease with increased K supply, demonstrating competition for uptake.
“15 ppm of K was insufficient for optimal growth and function in both genotypes and elicited
visual deficiency symptoms. Biomass of leaves, stems, and roots increasing with the increase in K
concentration, up to 175 ppm K, and decreasing with further increase in concentration, hence presenting
15 ppm as a sub-optimal concentration and 175 ppm as an optimal K
concentration. 240 ppm K proved excessive and damaging to
development of the genotype Royal Medic, while in Desert Queen it
stimulated rather than restricted shoot and root development.”
Vegetative Growth
K – 175 (up to 240 ppm)
Nitrogen, Flowering Cycle.
Nitrogen supply affects cannabinoid and terpenoid profile in medical cannabis (2021)
Avia Saloner and Nirit Bernstein
“We studied the impact of N application on chemical
and functional-physiology phenotyping in medical cannabis
at the flowering stage. The plants were grown under five N
treatments of 30, 80, 160, 240, and 320 mg L (ppm), for 56
days, and light was supplied by HPS bulbs (980 μmol m2 s1).
“These results suggest that high N supply has
adverse effects on the production of secondary compounds in
cannabis, while it promotes growth and biomass production.
Our results demonstrate that N supply up to 160 mg L,
dramatically increased inflorescence biomass, while higher
application levels did not induce an additional significant
effect. Taken together with the negative impacts obtained for
high N supply on secondary metabolite accumulation, we
suggest that the optimal level for excelled yield quantity, as
well as quality, i.e., high secondary metabolites profile, is
160 mg L N.”
Flowering growth
N - 160 mg L
Phosphorous, Flowering growth.
The Highs and Lows of P Supply in Medical Cannabis: Effects on Cannabinoids, the Ionome, and Morpho-Physiology (2021)
Sivan Shiponi and Nirit Bernstein
“The plants in each group received one of five P concentrations (5,
15, 30, 60, and 90 mg L P), and short photoperiod was applied (12/12-h
light/dark) using high-pressure sodium bulbs (980 mmol m2 s1) for 63
and 68 days for Desert Queen and Royal Medic, respectively. This
concentration range was chosen with the goal to target deficiency as
well as over-supply of P.
“Cannabinoid concentrations decreased linearly with increasing yield, consistent with a yield
dilution effect, but the total cannabinoid content per plant increased with increasing P supply. These results
reveal contrasting trends for effects of P supply on cannabinoid concentrations that were highest under <30
mg L P, vs. inflorescence biomass that was highest under 30–90 mg L P.
“Cannabinoid concentrations in the inflorescence were affected by the P treatments and overall
reduced with the increase in P supply. THCA and CBDA concentrations had the most profound response to
P concentrations and were reduced with P supplement in both genotypes and at both locations in the plant
(i.e., in the primary and secondary inflorescences). The foremost discovery is the contrasting effect of
increasing P supply to increase inflorescence yield production but to decrease the biosynthesis.”
Flowering growth
P - 60 mg L average (30-90 mg L)
Potassium, Flowering growth.
Effect of Potassium (K) Supply on Cannabinoids, Terpenoids and Plant Function in Medical Cannabis (2022)
Avia Saloner and Nirit Bernstein
Abstract
We have demonstrated in previous studies that the essential macro-nutrients nitrogen (N) and
phosporous (P) have profound effects on the production of cannabinoids and terpenoids in the
cannabis plant. The present study was undertaken to evaluate the hypothesis that potassium (K)
supply, which is known to substantially affect plant development and function, affects the
secondary metabolism of the cannabis plant. Two cultivars of medical cannabis were grown in
controlled environment conditions, under five levels of K supply: 15, 60, 100, 175, and 240 mg L−1 K.
The results revealed that the development and function of plants that received the low K supply of
15 mg L−1 K were impaired, as the plants suffered from visual chlorosis, and the inflorescence
yield was reduced in both cultivars. Plants that received higher K inputs in the range of −175 mg
L−1 K demonstrated optimal plant function and high yield, and one cultivar demonstrated oversupply
symptoms under the high K level of 240 mg L−1. The concentrations of most cannabinoids
and terpenoids declined with the elevation of K supply, thus supporting the hypothesis. As
secondary metabolite concentrations decreased with the increase in K supply, and higher K levels
had no positive effects, 60 mg L−1 K is the suggested application level to maintain high function
and yield combined with high secondary metabolism.
Flowering growth
P - 60 mg L average (30-90 mg L)