Light Recipes

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📄 New study on LED lighting strategies in eggplants

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Submitted by Elsewhere on 2021-Jan-14 Thu 06:16
2021-Jan-14 Thu 06:16
2715

Over the last decade, LED lighting has gained considerable interest as an energy-efficient supplemental light source in greenhouse horticulture that can change rapidly in intensity and spectral composition. Spectral composition not only affects crop physiology but may also affect the biology of…

The right light intensity and illumination length for plants

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Submitted by Elsewhere on 2021-Jan-04 Mon 13:30
2021-Jan-04 Mon 13:30
2638

Based on the plant's natural habitat, all plants and crops require a different light intensity in each growing phase for optimal plant development. Therefore, the required light intensity is different from crop to crop. Next to that, every crop is in need of a different illumination length. The HortiOne…

📄 Blocking light for postgrafting healing researched

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Submitted by Elsewhere on 2020-Dec-11 Fri 11:15
2020-Dec-11 Fri 11:15
2474

The use of tomato (Solanum lycopersicum) grafting is gaining traction across the United States, but small-scale growers face the challenge of creating optimum postgrafting healing conditions. The practice of blocking light for a period of 2 to 4 days while maintaining high humidity is commonly…

Growth of Cucumber Scions, Rootstocks, and Grafted Seedlings

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Submitted by Elsewhere on 2020-Dec-10 Thu 14:45
2020-Dec-10 Thu 14:45
2462

Irrigation scheduling and programming are very effective tools for efficient water use in a plant factory with artificial lighting (PFAL). In order to confirm optimal irrigation schemes for the production of cucumber scions and rootstocks in a PFAL, in this study, four different start points of irrigation were applied by measuring the weight of the plug tray to compare the growth of cucumber scions and rootstocks cultivated in a PFAL. Additionally, the growth characteristics of cucumber seedlings grafted with scions and rootstocks cultivated between in a greenhouse and in a PFAL were investigated. Although the growth of cucumber scions and rootstocks was highest when irrigation was conducted at 70% of water content in a medium, the growth of grafted cucumber seedlings before and after transplanting was not significantly different among the irrigation treatments in a PFAL. However, water use efficiency (WUE) during cucumber scions and rootstock production in a PFAL was higher at 60% than at 70%. Considering seedling growth and the efficiency of irrigation such as WUE and irrigation schedule, the optimal start point of irrigation during the production of cucumber scions and rootstocks in a PFAL was determined as 60% of water content in a medium.

Creating and modifying custom horticulture spectral solutions with online horticultural calculator

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Submitted by Elsewhere on 2020-Dec-10 Thu 13:30
2020-Dec-10 Thu 13:30
2454

Luminus Devices new horticulture calculator offers system engineers the opportunity to choose from over 30 of Luminus horticulture LEDs and create their own ‘recipe’ for specific luminaires and to save and output a complete LED bill of materials. System designers can select multiple LEDs and establish…

"Entire PAR-light range has function for crop"

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Submitted by Elsewhere on 2020-Dec-08 Tue 03:43
2020-Dec-08 Tue 03:43
2393

The plant uses barely fifty per cent of the sun’s radiation energy for photosynthesis. This part of sunlight is called PAR-light. Within this range all the wavelengths have a function, contrary to what was once thought. Plants use light for two things: photosynthesis and photomorphogenesis (control of…

What is the difference between Red/Blue vs. broad spectrum LEDs

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Submitted by Elsewhere on 2020-Dec-03 Thu 14:50
2020-Dec-03 Thu 14:50
2358

Growers generally have two options when it comes to horticultural LED spectrums – “full spectrum” or “broad-spectrum”, which appears white light; and “red/blue spectrum”, which can appear as purple or pink light.    The red/blue spectrum LED luminaires are often referred to as narrow band spectrum lights – because the…

CAN (ON): Cucumber grower continues through winter with LED interlighting

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Submitted by Elsewhere on 2020-Dec-02 Wed 13:23
2020-Dec-02 Wed 13:23
2328

Albuna Farms has chosen to install Philips GreenPower LED interlighting to grow lights in its greenhouse in Ruthven, Ontario. During the first phase of the project, Philips GreenPower LED interlighting grow lights will be installed on 4.7 hectares in their greenhouse. Albuna Farms expects the new system…

📄 Photoconversion fluoropolymer films for cultivating plants under conditions of insufficient insolation

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Submitted by Elsewhere on 2020-Nov-30 Mon 11:18
2020-Nov-30 Mon 11:18
2299

Plants are capable of using mainly the quanta of the red and blue parts of a spectrum for the reception of energy during photosynthesis. However, for many crops grown indoors in high latitudes or under conditions of insufficient insolation, the average daily intensity of the red and blue parts of the…

Growers learn to use 'x-factor' far-red in cucumber cultivation

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Submitted by Elsewhere on 2020-Nov-27 Fri 09:48
2020-Nov-27 Fri 09:48
2274

Growers, researchers and lighting suppliers agree, far-red is the 'x-factor', but when this x-factor should be deployed, that is a different story. At the Proefstation voor de Groenteteelt (testing station for vegetable cultivation) in the Belgian town Sint-Katelijne-Waver, they are conducting research…

📄 The Comparison of Constant and Dynamic Red and Blue Light Irradiation Effects on Red and Green Leaf Lettuce

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Submitted by Elsewhere on 2020-Nov-16 Mon 19:27
2020-Nov-16 Mon 19:27
2152

In this study, we sought to evaluate and compare the effects of constant and dynamic lighting on red and green leaf lettuce (Lactuca sativa L. Red Cos and Lobjoits Green cos) cultivated in a controlled environment. Plants were illuminated with the combination of red 662 and 638 nm, blue 452 nm, and far-red 737 nm at 16 h photoperiod and constant daily light integral (DLI) of each component. Five constant or dynamic lighting treatments were performed: (BR) constant flux of both B452 and R662; (B*R) constant flux of R662, but the DLI of B452 condensed in 8 h in the middle of photoperiod doubling the PPFD of blue light; (BR*) constant flux of B452, but the DLI of R662 light condensed in the middle of photoperiod; (BdynR) constant flux of R662, but the flux of B452 varies in the sinusoidal profile during 16 h photoperiod, imitating diurnal increase and decrease in lighting intensity; and (BRdyn) constant flux of B452, but the flux of R662 varies in sinusoidal profile. The lettuce’s response to dynamic lighting strategies was cultivar specific. Dynamic lighting strategies, mimicking natural lighting fluctuations, did not have a remarkable effect on photosynthesis and antioxidative parameters, but the dynamic flux of blue light component had a pronounced effect on higher macro and microelement contents in lettuce leaves.

Do you know the DLI of your geographic region?

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Submitted by Elsewhere on 2020-Nov-16 Mon 08:38
2020-Nov-16 Mon 08:38
2145

Do you know the DLI of your geographic region? Having the right DLI is important for consistent yields and quality. Discover your DLI by checking out this interactive map by Joanne Logan And James Faust myutk.maps.arcgis.com/apps/MapSeries…

📅 The importance of light quality in CEA systems

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Submitted by Elsewhere on 2020-Nov-11 Wed 08:46
2020-Nov-11 Wed 08:46
2124
500Foods shared this story from HD.com.

Spectrum has an important impact on plant growth, morphology, and development. Plants have evolved a sophisticated photoreceptor system capable of perceiving small changes on the light spectrum. Plants use spectral changes as information to adapt and increase survival and reproduction. Therefore, by…

The importance of light controllability for plant growth

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Submitted by Elsewhere on 2020-Nov-10 Tue 12:26
2020-Nov-10 Tue 12:26
2097

One of the most critical challenges—whether for greenhouse managers or for horticulture aficionados—is to provide plants with enough photoperiodic sunlight for effective photosynthesis, so that they can grow optimally regardless of the geographical location and climate. Winter months even in supposedly…

📄 Morphological and Physiological Responses of Cucumber Seedlings to Supplemental LED Light under Extremely Low Irradiance

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Submitted by Elsewhere on 2020-Nov-02 Mon 12:53
2020-Nov-02 Mon 12:53
2020

In order to inhibit spindling growth and improve quality of cucumber seedlings under low irradiance, effects of supplemental light-emitting diodes (LED) light (SL) on morphological and physiological characteristics of cucumber seedlings at different growth stages under extremely low irradiance (ELI) were investigated. Supplementary monochromatic, dichromatic and trichromatic LED light on cucumber seedlings were conducted in experiment one, and supplements of combination ratios and intensity of blue and red LED light (RB) were conducted in experiment two. The morphological and physiological parameters of cucumber seedlings were promoted effectively by supplemental monochromatic red light or dichromatic containing red light (RB and RG) under ELI as early as one-leaf seedling stage, as demonstrated by suppressed length of hypocotyl and first internode, increased stem diameter and biomass, higher net photosynthetic rate (Pn) and soluble sugar content. Monochromatic or additional green light was not beneficial to cucumber seedlings under the ELI. The length of shoot and hypocotyl decreased, while stem diameter and leaf area increased as early as one-leaf seedling stage by RB SL. Root activities, root–shoot ratio, activities of catalase (CAT) and peroxidase (POD), as well as palisade–spongy ratio in the leaf of cucumber seedlings were promoted effectively by increasing blue light proportion (1R1B/1R2B).

How far-red light enrichment modulates tomato resistance towards Botrytis cinerea

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Submitted by Elsewhere on 2020-Oct-30 Fri 13:15
2020-Oct-30 Fri 13:15
1984

Red and blue light are the major wavelength which are absorbed by leaf tissue and used for photosynthesis while others, i.e yellow and green light are reflected giving the plants their natural color. Far-red light (FR), which is invisible to the human eye, is transmitted by green plant tissues and…

Increasing growth of lettuce and mizuna under sole-source LED lighting

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Submitted by Elsewhere on 2020-Oct-30 Fri 13:13
2020-Oct-30 Fri 13:13
1987

Light recommendations for horticultural crops often focus on the optimal daily light integral (DLI) without regard to how that light is delivered throughout each day. Because photosynthesis is more efficient at lower photosynthetic photon flux density (PPFD), we hypothesized that longer photoperiods with…

Growth and Nutrient Element Content of Hydroponic Lettuce are Modified by LED Continuous Lighting of Different Intensities and Spectral Qualities

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Submitted by Elsewhere on 2020-Oct-29 Thu 12:55
2020-Oct-29 Thu 12:55
1982

LED red (R) and blue (B) continuous light (CL) is a potential efficient way to increaseplant productivity of plant factory with artificial light (PFAL), but limited information wasexplored about their effects on plant mineral nutrition. In an environmentally controlled plantfactory with artificial light (PFAL), the effects of CL of different intensities and spectral qualities,emitted by R and B LEDs on growth and nutrient element content and accumulation of lettuce(Lactuca sativa L.), were conducted in three hydroponic experiments. Two treatments, normal light(12 h/12 h) and CL (24 h/0 h) in experiment 1, three CL intensities (100, 200 and 300 μmol∙m−2∙s−1) inexperiment 2, and three CL light qualities (1R:3B, 1R:1B and 3R:1B) in experiment 3 weredesigned. The results showed that CL significantly increased the fresh and dry lettuce shootbiomass compared with normal light, and shoot fresh and dry biomass increased with theintensity increment of CL. In experiment 3, shoot fresh biomass was great under high R lightproportion CL treatment, while dry shoot biomass remained unchanged. Both CL and CL withincreased intensities promoted shoot C content and accumulation in lettuce. CL reduced N, P, K,Ca, Mg, Cu and Zn contents in lettuce shoot, while Fe and Mn contents did not change comparedto NL. Moreover, CL increased Ca, Fe and Mn accumulation.

Increasing Growth of Lettuce and Mizuna under Sole-Source LED Lighting Using Longer Photoperiods with the Same Daily Light Integral

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Submitted by Elsewhere on 2020-Oct-28 Wed 07:53
2020-Oct-28 Wed 07:53
1958

Light recommendations for horticultural crops often focus on the optimal daily light integral (DLI) without regard to how that light is delivered throughout each day. Because photosynthesis is more efficient at lower photosynthetic photon flux density (PPFD), we hypothesized that longer photoperiods with lower PPFD results in faster growth than shorter photoperiods with higher PPFD and the same DLI. We quantified the effect of different photoperiods, all providing the same DLI, on photosynthesis and growth of two leafy greens. Mizuna (Brassica rapa var. japonica) and lettuce (Lactuca sativa) “Little Gem” were grown from seed in a controlled environment chamber (20 °C and 819 µmol·mol−1 CO2) under six photoperiods (10, 12, 14, 16, 18, and 20 h). LED fixtures provided white light and PPFD was adjusted so each treatment received a DLI of 16 mol·m−2·d−1. Mizuna and lettuce were harvested 30 and 41 days after planting, respectively. Longer photoperiods with lower PPFD increased light interception, chlorophyll content index, quantum yield of photosystem II, and aboveground biomass, but decreased instantaneous CO2 assimilation of lettuce and mizuna. Aboveground biomass increased 16.0% in lettuce and 18.7% in mizuna in response to increasing the photoperiod from 10 to 20 h.

Increasing lettuce leaves' fresh weight by light treatments

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Submitted by Elsewhere on 2020-Oct-27 Tue 08:55
2020-Oct-27 Tue 08:55
1948

Material and methods: Sampling Location, hydroponic system and plant material ... Figure: Experimental vertical farming system realized in C-LED ...

Using LED grow lights and less irrigation makes stronger plants

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Submitted by Elsewhere on 2020-Sep-30 Wed 15:46
2020-Sep-30 Wed 15:46
1611

Hort Americas is currently working on a germination and propagation project of leafy greens and culinary herbs. The project is in collaboration with their demonstration greenhouse partners, The State Fair of Texas and the Big Tex Urban Farms. Big Tex Urban farms provide the labor needed to grow […]

Using LED grow lights and less irrigation makes stronger plants

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Submitted by Elsewhere on 2020-Sep-29 Tue 09:40
2020-Sep-29 Tue 09:40
1591

Hort Americas is currently working on a germination and propagation project of leafy greens and culinary herbs. The project is in collaboration with their demonstration greenhouse partners, The State Fair of Texas and the Big Tex Urban Farms. Big Tex Urban farms provide the labor needed to grow and…

End-Of-Day LED Lightings Influence the Leaf Color, Growth and Phytochemicals in Two Cultivars of Lettuce

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Submitted by Elsewhere on 2020-Sep-26 Sat 15:00
2020-Sep-26 Sat 15:00
1556

Four light treatments (W: white light; EOD-B: end-of-day enhanced blue light; EOD-FR: end-of-day supplementary far-red light; EOD-UV: end-of-day supplementary ultraviolet-A light) were designed to explore the effects of end-of-day (EOD) lightings (30 min before dark period) on leaf color, biomass and phytochemicals accumulation in two lettuce cultivars (Lactuca sativa cv. ‘Red butter’ and ‘Green butter’) in artificial light plant factory. EOD-FR stimulated the plant and shoot biomass of two cultivars, and EOD-B suppressed the growth of ‘Red butter’ but induced higher biomass in ‘Green butter’. EOD lightings generated brighter, greener and yellower leaf in ‘Red butter’ at harvest, but the highest lightness and the deepest redness of ‘Green butter’ leaf were observed in the middle growth stage. ‘Red butter’ had prominent higher contents of chlorophylls and carotenoids, while these pigments showed less sensitivity to the interaction of cultivars and EOD lightings. EOD lightings impeded the accumulation of anthocyanin in two cultivars, except EOD-UV slightly increased the anthocyanin contents in ‘Green butter’.

The keys of uniformity for plant growth

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Submitted by Elsewhere on 2020-Sep-24 Thu 08:06
2020-Sep-24 Thu 08:06
1518

Plants have evolved around the sun as their natural source of energy. This is important because the sun is at an infinite distance away, with a predictable cycle over the course of days and seasons. The more light a plant receives, the more it will grow and thrive. In the natural environment, when a…

What's the difference between broad full spectrum LEDs and red/blue LEDs?

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Submitted by Elsewhere on 2020-Sep-23 Wed 13:18
2020-Sep-23 Wed 13:18
1501

Growers generally have two options when it comes to horticultural LED spectrums – “full spectrum or broad-spectrum, which appears as white light; and red/blue spectrum, which can appear as purple or pink light.    

PL Light Systems releases leafy greens crop guide

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Submitted by Elsewhere on 2020-Sep-18 Fri 12:27
2020-Sep-18 Fri 12:27
1399

Greenhouse and indoor grown leafy greens and culinary herbs provide many advantages over field grown crops, including a more stable climate, more consistent time to harvest, the ability to control lighting, shading, CO2, and increased food safety. Low ambient light levels in the winter and on cloudy…

'We are developing a sustainable technology that uses 75% less LED lighting'

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Submitted by Elsewhere on 2020-Sep-08 Tue 10:13
2020-Sep-08 Tue 10:13
1257

Verde Compacto, a Mexican start-up, producer of container farms and indoor farming growing technologies, has seen significant demand for their growing systems during the pandemic.  'COVID is driving this market forward because people want to know what is behind their food and their diets. Logistic chains in…

Comparison of costs in greenhouse cucumber with LED or HPS

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Submitted by Elsewhere on 2020-Sep-08 Tue 10:12
2020-Sep-08 Tue 10:12
1262

The amount of energy used in agricultural production, processing and distribution is constantly increasing. During the winter months in the greenhouse production industry, the supplemental lighting required to keep up production levels results in high expenditure. Current technology uses broadband…

Far-red light enhances density of tomato seedlings

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Submitted by Elsewhere on 2020-Sep-03 Thu 09:28
2020-Sep-03 Thu 09:28
1217

Brandon Huber, a Ph.D. candidate of Horticultural Science, shared some of his tomato research to help people better understand indoor controlled environmental horticulture and its impact on young plant production. While studying indoor controlled environmental horticulture under the direction of Ricardo…

How to maximize yields with lighting strategies

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Submitted by Elsewhere on 2020-Aug-27 Thu 09:23
2020-Aug-27 Thu 09:23
1149

With a rapidly expanding legal cannabis market in North America, we are seeing an increase in the number of cultivation operations in both indoor and greenhouse applications. Growing cannabis in a controlled environment, allows for control over many environmental factors – including lighting, temperature,…