Abstract
Light quality plays a decisive role in controlled-environment agriculture, shaping plant morphology, physiology, and productivity. This study investigated the impact of far-red (FR) light on Cannabis sativa L. by comparing two different application strategies: continuous FR supplementation throughout 12 h of the photoperiod and end-of-day (EOD) FR exposure applied only at the end of the light period. In both treatments, FR was added to a background spectrum of red and blue (RB) light, while a control group grown under RB light alone was included to assess the specific effects of FR on plant growth, physiological responses, and flowering. Continuous FR exposure induced pronounced shade-avoidance traits, increasing plant height by 9% and petiole length by 17% relative to the control, and raised leaf dry weight to 12.9 g, 9% higher than under EOD (11.7 g) and 16.3% higher than under RB alone (10.8 g). Besides plant height and petiole length, both FR and EOD treatment induced limited morphological adjustments but increased chlorophyll content by 9%, resulting in greater canopy expansion and photosynthetic potential. However, flowering time was unaffected by spectral treatment, confirming that Cannabis floral induction is tightly regulated by photoperiod rather than light quality. Energy-use analysis revealed that EOD supplementation achieved many of the benefits of continuous FR while reducing overall consumption, but energy-use efficiency analysis proved FR as the more efficient treatment. These findings highlight the potential of FR light, particularly when applied continuously, to optimize vegetative growth and canopy physiology in controlled-environment Cannabis cultivation, while EOD strategies offer a practical compromise between cost savings and physiological benefits.
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Claims 12
Claim · model-written summary
Continuous far-red exposure increased plant height by 9% relative to the control in cannabis.
- Taxon
- Cannabis sativa L.
Cannabis sativae0 - Treatment
- Continuous FR exposuree1
- Outcome
- plant heighte1
- Direction
- increasinge1
- Value
- 9%e1
- Comparator
- controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“Continuous FR exposure induced pronounced shade-avoidance traits, increasing plant height by 9% and petiole length by 17% relative to the control”
Claim · model-written summary
Continuous far-red exposure increased petiole length by 17% relative to the control in cannabis.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- Continuous FR exposuree1
- Outcome
- petiole lengthe1
- Direction
- increasinge1
- Value
- 17%e1
- Comparator
- controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“Continuous FR exposure induced pronounced shade-avoidance traits, increasing plant height by 9% and petiole length by 17% relative to the control”
Claim · model-written summary
Continuous far-red raised leaf dry weight by 9% relative to end-of-day far-red.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- continuous FR supplementatione5
- Outcome
- leaf dry weighte2
- Direction
- highere2
- Value
- 9%e2
- Comparator
- EODe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e2“raised leaf dry weight to 12.9 g, 9% higher than under EOD (11.7 g) and 16.3% higher than under RB alone (10.8 g)”
e5“continuous FR supplementation throughout 12 h of the photoperiod”
Claim · model-written summary
Continuous far-red raised leaf dry weight by 16.3% relative to red and blue light alone.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- continuous FR supplementatione5
- Outcome
- leaf dry weighte2
- Direction
- highere2
- Value
- 16.3%e2
- Comparator
- RB alonee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e2“raised leaf dry weight to 12.9 g, 9% higher than under EOD (11.7 g) and 16.3% higher than under RB alone (10.8 g)”
e5“continuous FR supplementation throughout 12 h of the photoperiod”
Claim · model-written summary
Far-red light increased chlorophyll content by 9% relative to the control in cannabis.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- FRe3
- Outcome
- chlorophyll contente3
- Direction
- increasede3
- Value
- 9%e3
- Comparator
- controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“Continuous FR exposure induced pronounced shade-avoidance traits, increasing plant height by 9% and petiole length by 17% relative to the control”
e3“both FR and EOD treatment induced limited morphological adjustments but increased chlorophyll content by 9%”
Claim · model-written summary
End-of-day far-red increased chlorophyll content by 9% relative to the control in cannabis.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- end-of-day (EOD) FR exposuree4
- Outcome
- chlorophyll contente3
- Direction
- increasede3
- Value
- 9%e3
- Comparator
- controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“Continuous FR exposure induced pronounced shade-avoidance traits, increasing plant height by 9% and petiole length by 17% relative to the control”
e3“both FR and EOD treatment induced limited morphological adjustments but increased chlorophyll content by 9%”
e4“end-of-day (EOD) FR exposure applied only at the end of the light period”
Claim · model-written summary
Flowering time in cannabis was unaffected by spectral treatment.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- spectral treatmente4
- Outcome
- flowering timee4
- Direction
- unaffectede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e4“flowering time was unaffected by spectral treatment”
Claim · model-written summary
Cannabis floral induction is regulated by photoperiod rather than light quality, according to the authors.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Outcome
- floral inductione5
- Qualifier
- regulated by photoperiod rather than light qualitye5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e5“Cannabis floral induction is tightly regulated by photoperiod rather than light quality”
Claim · model-written summary
End-of-day supplementation reduced overall energy consumption relative to continuous far-red.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- EOD supplementatione7
- Outcome
- overall consumptione7
- Direction
- reducinge7
- Qualifier
- achieved many of the benefits of continuous FRe7
- Comparator
- continuous FRe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e7“EOD supplementation achieved many of the benefits of continuous FR while reducing overall consumption”
Claim · model-written summary
Far-red light was the more energy-efficient treatment in the energy-use analysis.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Treatment
- FRe6
- Outcome
- energy-use efficiencye6
- Direction
- more efficiente6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e6“energy-use efficiency analysis proved FR as the more efficient treatment”
Claim · model-written summary
End-of-day strategies are recommended as a practical compromise between cost savings and physiological benefits.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Outcome
- practical compromise between cost savings and physiological benefitse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“EOD strategies offer a practical compromise between cost savings and physiological benefits”
Claim · model-written summary
Continuous far-red light is suggested to optimize vegetative growth and canopy physiology in cannabis.
- Taxon
- Cannabis sativa L.Cannabis sativae0
- Outcome
- vegetative growth and canopy physiologye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cannabis sativa L.”
e1“particularly when applied continuously, to optimize vegetative growth and canopy physiology”
The same questions in other papers
light · physiology: pigments · Cannabis sativaPositive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
light · growth · Cannabis sativaPositive and negative results
10 papers in the same direction as this paper · 1 in the opposite direction · 1 reporting no difference from an alternative
- positive
- no effect
- no effect
9 papers more in this group
See all 13 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.