Light

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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

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…

Simulate the light transmission of your greenhouse project with Hortinergy

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Submitted by Elsewhere on 2020-Dec-03 Thu 14:48

Simulate the light transmission of your greenhouse project with Hortinergy

You can simulate with Hortinergy  the light transmission and heat losses of your greenhouse project with our large library of transparent and opaque covers.

Hortinergy’s latest update includes a complete library of transparent and diffusing covers (glass, plastic, etc.).

The transmission models of plastic foils (clear, diffuse)  have been validated in the research greenhouses at ASTREDHORRATHO with an accuracy of 95% within the Dilight project.

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📄 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

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…

📄 Leaf Response to Different Light Spectrum Compositions during Micropropagation of Gerbera Axillary Shoots

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Submitted by Elsewhere on 2020-Nov-21 Sat 23:49

The experiment evaluated the influence of different light qualities and 6-benzyladenine (BA) concentration in a medium on the leaf response of multiplied Gerbera jamesonii Bolus ex Hook. f.‘Big Apple’ shoots. Three different light-emitting diode (LED) spectra—100% blue (B), 100% red (R) and red and blue mixture (7:3, RB)—were used, and a fluorescent lamp was used as a control (Fl). Concentrations of BA in Murashige and Skoog (MS) medium were 1, 2.5 and 5 µM. Leaves developed under 100% blue light had a lower frequency of stomata and a smaller area as compared with those from plants exposed to light with red in spectrum. Under 100% red light, the leaf area and the frequency of stomata increased along with growing concentration of BA in the medium. The thickest mesophyll was spotted in the cross-section of leaves exposed to the blue LED light. Leaves developed under the 100% red light had the thinnest mesophyll layers. Increasing concentration of BA in the medium resulted in enhanced leaf blade thickness. The cross-section of leaf vascular bundles was only half of that in petioles. The leaves under the LED combinations had larger vascular bundles than those under fluorescent light. The highest level of photosynthetic pigments was noticed in the leaves grown under LED R and RB lights. Our study demonstrated that 2.5 µM BA and a mixture of blue and red light provided by LED improved leaf quality during multiplication of gerbera shoots.

Reproducing sunlight in controlled laboratory environments

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Submitted by Elsewhere on 2020-Nov-06 Fri 11:03

Plants and more generally, photosynthetic organisms need light to live. Exposed to artificial light, plants implement adaptation processes. All these adaptation strategies are studied in agronomic research and plant biology laboratories, in particular at CEA Cadarache, within the Institut de Biosciences…

Advantages of using 7 layer film for a greenhouse covering

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Submitted by Elsewhere on 2020-Nov-02 Mon 13:22

Greenhouses are used to grow plants and crops as they require controlled climatic conditions. Greenhouse covering comes in various materials. 7 layer film for Greenhouse Covering is preferred by producers because of the advantages it gives. It is not much costly and the quality of the crop is maintained.…

📄 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

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). Increasing light intensity (50/75) enhanced soluble sugar accumulation in leaves. There were synergistic effects of RB ratio and light intensity on increasing stem diameter, leaf area, seedling index and decreasing hypocotyl cell area of the vertical section. In conclusion, 1R2B-75 may be the optimal SL to inhibit spindling growth of cucumber seedlings under ELI condition.

Leamington waits to follow Kingsville’s lead on ‘light pollution’ bylaw

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

One day after Kingsville’s town council unanimously approved a bylaw to stop light pollution from greenhouses and odours from cannabis production, Leamington’s council voted unanimously to seek more information from growers and the public before considering a light pollution bylaw. Kingsville’s bylaw…

Evaluation of the Light Environment of a Plant Factory with Artificial Light by Using an Optical Simulation

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

Good lighting designs can establish suitable light environments in plant factories with artificial light (PFALs). This study used optical simulations to investigate the effects of lighting designs in PFALs on the coefficient of variation of light absorption (Φp; CV) of individual plants and the coefficient of utilization for the lighting system (U). Three-dimensional models of canola plants were constructed using a scanner, and a 3D model of the cultivation shelf was also created. The photosynthetic photon flux density (PPFD) distribution in the cultivation spaces, with or without the canola plants, was estimated first. The PPFD on the canola leaves was then estimated when the lighting design parameters, such as number, distance, height, radiant flux, and light distribution of the light-emitting diode lamps, were modified. The optical simulation showed good accuracy when estimating the PPFD distributions on the cultivation shelf and the leaves of the canola plants. The results showed that while the PPFD distribution across the growing area was uniform, it was not on a plant canopy. By appropriately controlling the layout of the lamps and their directionality, lighting designs that reduce Φp; CV and improve U in PFAL could be possible, and optical simulations could help to develop them.

"Light transmission of glass becomes more and more important”

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Submitted by Elsewhere on 2020-Oct-14 Wed 13:02

The characteristics of the glass are important. Steven Adriaense, Van Looveren explains: “The light transmission is vital. That’s what it is all about now. The requirements are getting higher and higher these days. In order to show the product has a good light transmission, we supply the requested…

In high-wire cultivation, it's important that the light penetrates deep into the crop

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Submitted by Elsewhere on 2020-Oct-06 Tue 12:35

Many growers who invest in LED lighting opt for wide-beam LED fixtures with a high light output. In this way, they aim to achieve optimal light distribution at the top of the crop and to limit investment costs. In high-wire crops, however, it is particularly important that the light penetrates deep into…

New agent cleans glass but does not affect anti-reflective coating

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Submitted by Elsewhere on 2020-Jul-24 Fri 09:42

In a greenhouse, every percent of light counts. The arrival of diffuse glass with an anti-reflection coating provides a high light transmission and therefore a higher yield. However, also for this glass, the advantage does not hold up if the glass is dirty. A new cleaning agent that cleans the glass…