Light Recipes

While light-emitting diodes have provided botanists with the ability to generate precisely controlled SPDs for their research, the use of colloquial color names in their published papers has made it difficult to interpret and summarize their research results for the horticultural industry. This paper…

"Signify’s expanded GrowWise Control System helps growers boost operational efficiencies. This allows for full dimming for Philips toplighting compact in greenhouses. Besides, it enables growers to plan and automate light recipes one year ahead and to control the grow lighting through their climate…

LED lighting is appointed as the successor of HPS lighting in greenhouses since it can lead to a more sustainable cultivation, i.e. it converts electrical energy into photosynthetically active radiation more efficiently. To quantify the effect of this more efficient conversion within the operation of the…

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…

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…

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…

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.

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…

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…

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…

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…

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, 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…

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? 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…

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…

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…

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).

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…

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…

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.

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.

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

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 […]

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…

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’.

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…

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.    

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…

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…