Uploaded August 2025 | Updated September 2026, 2 weeks ago
Improving Flower Mass and Metabolites with High Light Intensity
Professor DeBacco
Research Article
Sae-Tang, W., Heuvelink, E., Nicole, C. C., Kaiser, E., Sneeuw, K., Holweg, M. M., ... & Marcelis, L. F. (2024). High light intensity improves yield of specialized metabolites in medicinal cannabis (Cannabis sativa L.), resulting from both higher inflorescence mass and concentrations of metabolites. Journal of Applied Research on Medicinal and Aromatic Plants, 43, 100583.
sciencedirect.com/science/article/pii/S2214786124000561
Light Specifics Used in Climate Controlled Chamber
Broad-band white LEDs at three light intensities: 600, 800, and 1000 μmol m-2 s-1 photosynthetic photon flux density (PPFD)
PPFD was 423 ± 24 μmol m-2 s-1
13 % blue (400–500 nm)
6 % green (500–600 nm)
81 % red (600–700 nm)
less than 0.6 % far-red (700–800 nm)
Note: (LEDs, Green Power DRW MB 1.2, Philips, the Netherlands).
The photoperiod was 18/6 hours (light/dark).
PPFD and spectrum was measured at 45 cm above the table, which was at final canopy height during the vegetative phase.
Applied during the flower phase (8 weeks with a 12-h photoperiod)
Climate Controlled Chamber Environment
During the vegetative phase (0–11 DAT), the climate was…
28.7/26.3◦C (light/dark)
79/86 %RH
During the flower phase (12–69 DAT), the climate was…
28.0/26.7 ◦C
71/75 % RH
Cultivar grown: Cannabis cv. ‘Critical CBD’
Chemotype II with an intermediate THC/CBD ratio of approximately 0.5
Relative Abundance of Cannabinoids in Flower
Concentrations of detected cannabinoids increased with PPFD.
Relative Abundance of Terpens in Flower
Concentrations of both sesquiterpenoids and monoterpenoids increased linearly with PPFD in plants during the 6–8 weeks into the generative phase
Total terpenoids concentration in fresh flower increased by 76% with a 67% increase in light intensity.
Increase was mainly observed for individual monoterpenoids like limonene and myrcene.
Cannabis grown at 600, 800, and 1000 μmol m-2 s-1 PPFD
After 8 weeks into the flower phase.
Plant dry mass (A)
Dry mass partitioning (B)
Dry matter content (C)
Light use efficiency (D)
Data based on two replicate experiments (n=2), each consisting of 30 (replicate 1) and 18 (replicate 2) plants per treatment.
*When linear effects of light intensity were significant at P=0.05, trendlines are depicted.
Cannabis grown at 600, 800, and 1000 μmol m-2 s-1 PPFD
After 8 weeks into the flower phase.
Plant height (A)
Diameter of the main stem (B)
Plant compactness (C)
Leaf area (LA) and specific leaf area (SLA) (D)
Data based on two replicate experiments (n=2), each consisting of 30 (replicate 1) and 18 (replicate 2) plants per treatment.
*When linear effects of light intensity were significant at P=0.05, trendlines are depicted.
Light Response Curves of Net Photosynthesis Rate
Cannabis grown under 600, 800, and 1000 μmol m-2 s-1 PPFD at…
3 (A), 5 (B), and 7 (C) weeks into the flower phase.
Derived from Light Response Curves…
(D) Parameters maximum estimated photosynthesis rate (Amax)
(E) Apparent quantum yield (α)
(F) Light compensation point (LCP)
(G) Dark respiration (Rd)
Analysis of the Effects of Light Intensity (600 to 1000 umol m-2 s-1) during 8 weeks into Flower
Increasing Yield with Increasing Light Intensity
Yield of specialized metabolites (cannabinoids and terpenoids) strongly increased in both their concentration and flower yield with increasing light intensity (600–1000 μmol m-2 s-1)
Within this range of light intensities, the inflorescence yield showed a proportional increase with light intensity, meaning that light use efficiency remained constant.
Increased Yield Due to Higher Dry Matter
Higher inflorescence yield was mainly due to higher total plant dry matter production.
To a lesser extent due to an increase in the fraction of dry mass partitioned to the inflorescences.
Cannabis has High Photosynthetic Capacity
Leaf photosynthesis rate kept on increasing up to the highest measuring light level (3000 μmol m-2 s-1)
Indicating that Cannabis is a species with exceptionally high photosynthetic capacity
However, when it comes to indoor growing the investment of generating high light intensities must be balanced by cost and return on input data.
Recommendation: 1000 umol m-2 s-1 of light
This offers the highest yield while still justifying the cost to generate this level of light intensity.
Link to Lecture Slides: drive.google.com/file/d/1NDTY3YLWtZ-vxwrZViPSAcmzh2uQ7fRc/view?usp=drive_link
*Due to the description character limit the full work cited for "Improving Flower Mass and Metabolites with High Light Intensity" can be viewed at... docs.google.com/document/d/1cyngu2CCqSKoAkjklY68k8Idqog6AkPj/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
Improving Flower Mass and Metabolites with High Light Intensity
Professor DeBacco
Research Article
Sae-Tang, W., Heuvelink, E., Nicole, C. C., Kaiser, E., Sneeuw, K., Holweg, M. M., ... & Marcelis, L. F. (2024). High light intensity improves yield of specialized metabolites in medicinal cannabis (Cannabis sativa L.), resulting from both higher inflorescence mass and concentrations of metabolites. Journal of Applied Research on Medicinal and Aromatic Plants, 43, 100583.
sciencedirect.com/science/article/pii/S2214786124000561
Light Specifics Used in Climate Controlled Chamber
Broad-band white LEDs at three light intensities: 600, 800, and 1000 μmol m-2 s-1 photosynthetic photon flux density (PPFD)
PPFD was 423 ± 24 μmol m-2 s-1
13 % blue (400–500 nm)
6 % green (500–600 nm)
81 % red (600–700 nm)
less than 0.6 % far-red (700–800 nm)
Note: (LEDs, Green Power DRW MB 1.2, Philips, the Netherlands).
The photoperiod was 18/6 hours (light/dark).
PPFD and spectrum was measured at 45 cm above the table, which was at final canopy height during the vegetative phase.
Applied during the flower phase (8 weeks with a 12-h photoperiod)
Climate Controlled Chamber Environment
During the vegetative phase (0–11 DAT), the climate was…
28.7/26.3◦C (light/dark)
79/86 %RH
During the flower phase (12–69 DAT), the climate was…
28.0/26.7 ◦C
71/75 % RH
Cultivar grown: Cannabis cv. ‘Critical CBD’
Chemotype II with an intermediate THC/CBD ratio of approximately 0.5
Relative Abundance of Cannabinoids in Flower
Concentrations of detected cannabinoids increased with PPFD.
Relative Abundance of Terpens in Flower
Concentrations of both sesquiterpenoids and monoterpenoids increased linearly with PPFD in plants during the 6–8 weeks into the generative phase
Total terpenoids concentration in fresh flower increased by 76% with a 67% increase in light intensity.
Increase was mainly observed for individual monoterpenoids like limonene and myrcene.
Cannabis grown at 600, 800, and 1000 μmol m-2 s-1 PPFD
After 8 weeks into the flower phase.
Plant dry mass (A)
Dry mass partitioning (B)
Dry matter content (C)
Light use efficiency (D)
Data based on two replicate experiments (n=2), each consisting of 30 (replicate 1) and 18 (replicate 2) plants per treatment.
*When linear effects of light intensity were significant at P=0.05, trendlines are depicted.
Cannabis grown at 600, 800, and 1000 μmol m-2 s-1 PPFD
After 8 weeks into the flower phase.
Plant height (A)
Diameter of the main stem (B)
Plant compactness (C)
Leaf area (LA) and specific leaf area (SLA) (D)
Data based on two replicate experiments (n=2), each consisting of 30 (replicate 1) and 18 (replicate 2) plants per treatment.
*When linear effects of light intensity were significant at P=0.05, trendlines are depicted.
Light Response Curves of Net Photosynthesis Rate
Cannabis grown under 600, 800, and 1000 μmol m-2 s-1 PPFD at…
3 (A), 5 (B), and 7 (C) weeks into the flower phase.
Derived from Light Response Curves…
(D) Parameters maximum estimated photosynthesis rate (Amax)
(E) Apparent quantum yield (α)
(F) Light compensation point (LCP)
(G) Dark respiration (Rd)
Analysis of the Effects of Light Intensity (600 to 1000 umol m-2 s-1) during 8 weeks into Flower
Increasing Yield with Increasing Light Intensity
Yield of specialized metabolites (cannabinoids and terpenoids) strongly increased in both their concentration and flower yield with increasing light intensity (600–1000 μmol m-2 s-1)
Within this range of light intensities, the inflorescence yield showed a proportional increase with light intensity, meaning that light use efficiency remained constant.
Increased Yield Due to Higher Dry Matter
Higher inflorescence yield was mainly due to higher total plant dry matter production.
To a lesser extent due to an increase in the fraction of dry mass partitioned to the inflorescences.
Cannabis has High Photosynthetic Capacity
Leaf photosynthesis rate kept on increasing up to the highest measuring light level (3000 μmol m-2 s-1)
Indicating that Cannabis is a species with exceptionally high photosynthetic capacity
However, when it comes to indoor growing the investment of generating high light intensities must be balanced by cost and return on input data.
Recommendation: 1000 umol m-2 s-1 of light
This offers the highest yield while still justifying the cost to generate this level of light intensity.
Link to Lecture Slides: drive.google.com/file/d/1NDTY3YLWtZ-vxwrZViPSAcmzh2uQ7fRc/view?usp=drive_link
*Due to the description character limit the full work cited for "Improving Flower Mass and Metabolites with High Light Intensity" can be viewed at... docs.google.com/document/d/1cyngu2CCqSKoAkjklY68k8Idqog6AkPj/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
