Evaluating operating characteristics of light sources for horticultural applications

Wallace, C. S.; Both, Arend-Jan

doi:10.17660/actahortic.2016.1134.55

Cited by 40 publications

(35 citation statements)

References 3 publications

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“…Interestingly, in 2014, the electrical efficacy of evaluated LED fixtures was no better than the best HPS fixtures [15]. However, by 2016, the best evaluated LED fixture was 40% more efficacious than HPS [6]. Historically, HID fixtures have been used for supplemental lighting, but LED adoption is increasing within the greenhouse industry.…”

Section: Discussionmentioning

confidence: 99%

“…Though previous research has shown that yield and morphology response to spectral quality in lettuce is highly cultivar dependent, it has not been shown whether those responses remain the same within the same type of cultivar, e.g., all red leaf or romaine lettuce react the same under the same spectral treatments [8]. Some LEDs on the market now have greater PAR efficacy than HID [6], but more work is needed to test fixture biomass efficacy, to determine if their adoption will ultimately lead to reduced energy use by the controlled environment agriculture (CEA) industry.…”

Section: Introductionmentioning

confidence: 99%

“…With the advancement of LED technology, there are some advantages of LEDs as compared to existing horticultural lights (HPS and metal halide). Examples include photosynthetically active radiation (PAR) efficacy [6], the ability to target specific wavebands/spectra of light, finer control over light intensity and periodicity of lighting [7], and a lower heat load produced in the direction of the light allowing them to be placed closer to a crop or operated during warm ambient conditions [5,8]. When comparing potential for energy savings in LED over HPS lights the PAR efficacy, light output per unit electricity (units: µmol/j) is used [9].…”

Section: Introductionmentioning

confidence: 99%

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Quality, Yield, and Biomass Efficacy of Several Hydroponic Lettuce (Lactuca sativa L.) Cultivars in Response to High Pressure Sodium Lights or Light Emitting Diodes for Greenhouse Supplemental Lighting

2020

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Lettuce is an economically important crop that can be grown either in the field or greenhouse. Different challenges are present in either environment; therefore, cultivar selection is important. For hydroponic greenhouse lettuce there is relatively little published information on cultivar selection under different lighting sources. The objective of phase 1 was to determine the influence of lighting using high pressure sodium (HPS) or light emitting diodes (LED) on plant fresh weight, height, tip burn index, bolting, and Brix. Phase 2 was similar to phase 1 but with fewer cultivars (1) to allow for greater number of replicates per treatment per crop cycle. Each experiment consisted of three crop cycles over time per phase. Light sources were controlled using an algorithm, Light and Shade System Implementation (LASSI), to achieve a constant average daily light integral under each treatment and crop cycle. Electrical consumption and efficacy (fresh weight per kWh) from each treatment was estimated using data collected on power consumption from representative lamps multiplied by the number of fixtures and the hours fixtures were on per crop cycle. In phase 1, the fresh weight of 2 to 3 cultivars was greater under HPS and 1 to 2 cultivars under LED, depending on production cycle. The HPS-grown lettuce tended to have more tip burn and bolting in crop cycles 1 and 2, with cycle 3 showing similar tip burn incidence. Bolting was only consistently observed in one cultivar, ‘Teodore’. The LED array used less than half as much electricity as the HPS array, while producing relatively similar size lettuce, therefore, leading to electrical efficacies two- to three-times higher in LED than in HPS treatments. In phase 2, significant differences in height were found in ‘Greenstar’ and ‘Xandra’, with HPS producing larger plants than LED. Significant differences were also found in diameter in ‘Greenstar’, ‘Xandra’, ‘Locarno’, and ‘Crunchita’, with HPS again being larger than LED.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quality, Yield, and Biomass Efficacy of Several Hydroponic Lettuce (Lactuca sativa L.) Cultivars in Response to High Pressure Sodium Lights or Light Emitting Diodes for Greenhouse Supplemental Lighting

2020

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“…However, advancements such as electronic ballasts and double-ended lamps have led to a competitive environment regarding the most efficient and cost-effective source for greenhouse SL. For example, recent studies have reported that commercially available LED fixtures are similar or have become more energy-efficient than doubleended HPS lamps (Nelson and Bugbee, 2014;Wallace and Both, 2016).…”

mentioning

confidence: 99%

Comparison of Supplemental Lighting Provided by High-pressure Sodium Lamps or Light-emitting Diodes for the Propagation and Finishing of Bedding Plants in a Commercial Greenhouse

Craver¹,

Boldt²,

López³

2019

horts

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High-quality young plant production in northern latitudes requires supplemental lighting (SL) to achieve a recommended daily light integral (DLI) of 10 to 12 mol · m L2 · d L1 . High-pressure sodium (HPS) lamps have been the industry standard for providing SL in greenhouses. However, high-intensity light-emitting diode (LED) fixtures providing blue, white, red, and/or far-red radiation have recently emerged as a possible alternative to HPS lamps for greenhouse SL. Therefore, the objectives of this study were to 1) quantify the morphology and nutrient concentration of common and specialty bedding plant seedlings grown under no SL, or SL from HPS lamps or LED fixtures; and 2) determine whether SL source during propagation or finishing influences finished plant quality or flowering. The experiment was conducted at a commercial greenhouse in West Lafayette, IN. Seeds of New Guinea impatiens (Impatiens hawkeri 'Divine Blue Pearl'), French marigold (Tagetes patula 'Bonanza Deep Orange'), gerbera (Gerbera jamesonii 'Terracotta'), petunia (Petunia 3hybrida 'Single Dreams White'), ornamental millet (Pennisetum glaucum 'Jester'), pepper (Capsicum annuum 'Hot Long Red Thin Cayenne'), and zinnia (Zinnia elegans 'Zahara Fire') were sown in 128-cell trays. On germination, trays were placed in a double-poly greenhouse under a 16-hour photoperiod of ambient solar radiation and photoperiodic lighting from compact fluorescent lamps providing a photosynthetic photon flux density (PPFD) of 2 mmol · m L2 · s L1 (ambient conditions) or SL from either HPS lamps or LED fixtures providing a PPFD of 70 mmol · m L2 · s L1 . After propagation, seedlings were transplanted and finished under SL provided by the same HPS lamps or LED fixtures in a separate greenhouse environment. Overall, seedlings produced under SL were of greater quality [larger stem caliper, increased number of nodes, lower leaf area ratio (LAR), and greater dry mass accumulation] than those produced under no SL. However, seedlings produced under HPS or LED SL were comparable in quality. Although nutrient concentrations were greatest under ambient conditions, select macroand micronutrient concentrations also were greater under HPS compared with LED SL. SL source during propagation and finishing had little effect on flowering and finished plant quality. Although these results indicate little difference in plant quality based on SL source, they further confirm the benefits gained from using SL for bedding plant production. In addition, with both SL sources producing a similar finished product, growers can prioritize other factors related to SL installations such as energy savings, fixture price, and fixture lifespan.

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“…To remedy this issue, greenhouse operations use high-intensity electric lamps to provide SL, with a standard target PPFD of 70 to 90 mmol · m -2 · s -1 . Although HPS lamps are the current industry standard, LEDs have emerged as a competing SL source with regard to irradiance and efficacy (Nelson and Bugbee, 2014;Wallace and Both, 2016).…”

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confidence: 99%

Supplemental But Not Photoperiodic Lighting Increased Seedling Quality and Reduced Production Time of Annual Bedding Plants

Hurt¹,

López²,

Craver³

2019

horts

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In northern latitudes, the photosynthetic daily light integral can be less than 5 mol · m -2 · d -1 , necessitating the use of supplemental lighting (SL) to reduce bedding plant seedling production time and increase quality. Our objectives were 1) to quantify seedling quality and production time under continuous 16-h or instantaneous threshold SL, continuous lowintensity photoperiodic lighting (PL) for 16 or 24 hours with and without far-red light, or no electric lighting; and 2) to determine whether the described lighting treatments during propagation impact finished plant quality or flowering. Seeds of begonia (Begonia 3semperflorens) 'Bada Bing Scarlet', gerbera (Gerbera jamesonii) 'Jaguar Deep Orange', impatiens (Impatiens walleriana) 'Accent Premium Salmon', petunia (Petunia 3hybrida) 'Ramblin Peach Glo', and tuberous begonia (Begonia 3tuberosa) 'Nonstop Rose Petticoat' were sown in 128-cell trays and grown under either SL, PL, or no electric lighting (control). SL treatments consisted of high-intensity light-emitting diode (LED) or high-pressure sodium (HPS) lamps providing a photosynthetic photon flux density (PPFD) of either 70 mmol · m -2 · s -1 on continuously for 16 h · d -1 or 90 mmol · m -2 · s -1 based on an instantaneous threshold. PL treatments consisted of low-intensity red:white (R:W) or red:white:far-red (R:W:FR) lamps for 16 h · d -1 or R:W:FR lamps for 24 h · d -1 . Seedlings of gerbera, impatiens, and petunia from each treatment were subsequently transplanted and finished in a common greenhouse environment. The highest quality seedlings were grown under SL compared with PL or control conditions. When comparing SL treatments, seedlings produced under HPS or LED SL using an instantaneous threshold were of equal or greater quality compared with those under continuous SL with a 16-h photoperiod. Although the greater leaf area and internode elongation under PL may give growers the perception that seedling production time is reduced, PL did not increase biomass accumulation and seedling quality. Petunia seedlings propagated under HPS lamps using an instantaneous threshold flowered 4 to 11 days earlier compared with the other SL treatments. In addition, petunia propagated under R:W:FR PL for 16 h · d -1 flowered 5 to 7 days earlier compared with LED SL and the other PL treatments.

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Evaluating operating characteristics of light sources for horticultural applications

Cited by 40 publications

References 3 publications

Quality, Yield, and Biomass Efficacy of Several Hydroponic Lettuce (Lactuca sativa L.) Cultivars in Response to High Pressure Sodium Lights or Light Emitting Diodes for Greenhouse Supplemental Lighting

Quality, Yield, and Biomass Efficacy of Several Hydroponic Lettuce (Lactuca sativa L.) Cultivars in Response to High Pressure Sodium Lights or Light Emitting Diodes for Greenhouse Supplemental Lighting

Comparison of Supplemental Lighting Provided by High-pressure Sodium Lamps or Light-emitting Diodes for the Propagation and Finishing of Bedding Plants in a Commercial Greenhouse

Supplemental But Not Photoperiodic Lighting Increased Seedling Quality and Reduced Production Time of Annual Bedding Plants

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