The TLED is a 220 volt LED lamp with a very long lifespan (up to 50,000 hours). It is available in two powers - 26w / 54cm and 42w / 95cm - and two "colors" - Grow and Bloom, also known as Full Spectrum. The lamp is suitable for low plants, but can also be used to complete a lighting system by clamping it onto the vertical tubes of your grow room.
Light is qualified by QUALITY (SPECTRUM) and INTENSITY (P.A.R.).
LIGHT QUALITY
Light consists of photons that react as waves when they move. That is why we associate wavelengths with these photons. The photons that act on plants are located between the ultraviolet and the infrared spectrum, close to the visible light, from 350 to 750 nm (Fig 2).
• Near-ultraviolet (350-380 nm) : They help fight certain microorganisms and improve the immune system of plants.
• Visible (380-700 nm) : This is the spectrum that influences photosynthesis. The plant mainly absorbs blue and red light. In general, blue (430-500) light promotes growth and red (630-680) light promotes flowering and fruiting.
• Near-infrared (700-750 nm) : Also called "Dark Red" light. This light acts as a radiant heater and helps plants to stretch out towards the sun.
LIGHT INTENSITY
Only photons with a wavelength between 400 and 700 nm (close to the visible spectrum) participate in photosynthesis. These photons are called "Photosynthetically Active Radiation". The P.A.R. of a lighting system can be measured when it is alone (PPF-PPE) or part of a complete grow configuration (PPFD).
SINGLE LIGHTING SYSTEM
The lamp is placed in an Ulbritch-type sphere (Fig. 3), and all the photons it emits per second are measured. This yields the «Photosynthetic Photon Flux» (P.P.F. in μmol/s), which evaluates the potential photosynthetic capability of the lighting system. By the P.P.F. dividing by the consumed power, we obtain the «Photosynthetic Photon Efficacy» (P.P.E. in μmol/s/w or μmol/d), which allows us to evaluate the potential photosynthetic efficiency per consumed watt of an illumination system. Here are some P.P.E. values: Compact fluorescent lamps (CFL, TCL, T5...) = Less than 1 μmol/s/w, discharge lamps (HPS, MH, CMH...) = 1 to 2 μmol/s/w, light-emitting diodes (LED) : 2 to 3 μmol/s/w at the moment.
COMPLETE LIGHTING SYSTEM
The photons that fall on the surface of the crop are measured per m2 and per second. This is called the « Photosynthetic Photon Flux Density » (P.P.F.D. μmol/s/m2). This allows us to evaluate the actual photosynthetic capacity, per m2 on a crop surface. The P.P.F.D. is represented by a top view of the growing surface, with values taken every 15 x 15 cm (6" x 6") (Fig. 4). To simplify reading, we defined three colors for three levels of P.P.F.D. Level I : Less than 300 μmol/s/m2 = Propagation, seed, light growth, vegetative mode. Level II : 300 to 600 μmol/s/m2 : 300 to 600 μmol/s/m2 = Cultivation of sun-loving plants, intensive cultivation of shade-loving plants. Level III : More than 600 μmol/s/m2 = Intensive cultivation of sun-loving plants. NAMES OF LEDS There are two types of LEDs. Monochromatic LEDs emit photons that vibrate around one frequency. They are named according to their wavelength: 450 nm blue, 660 nm red... White LEDs have a wider spectrum. They come from a blue monochromatic LED, on which a phosphor layer has been applied, which shifts and smoothes the spectrum towards the yellow spectrum by lowering the energy of certain photons (Fig. 5). They are indicated by their color temperature, in Kelvin: 6500°K cold white, 5000/4000°K warm white, 3000/2700/2100°K yellow white. This method makes it possible to obtain LEDs that can be used for everyday lighting, but also for growing crops, thanks to their fuller spectrum
