Lighting Fundamentals

1. Intensity - The more intensity (quantity) of light the better your plants will grow. By increasing wattages you are increasing the intensity or quantity of light available for your plants. LED technology is unique in that it delivers more intensity at less wattage than traditional lighting and will continue to improve lumen/watts output levels. As light levels increase with traditional lighting such as high pressure sodium and metal halides environmental concerns must be monitored (heat, CO2, humidity, and nutrient supply). Environment must still be monitored with LED technology, however, the concerns are much less due to the low heat.

2. Spectrum - As light intensity increases, light spectrum becomes more important. Natural sunlight is intense and has a broad and balanced spectrum. Indoor plants require the same high intensity and broad but balanced spectrum. Two grow cycles (veg./cloning and flowering/bloom) require different spectrums to maximize results.

3. Focus - Delivering the light where it is needed in traditional lighting is the job of the reflector. Well designed reflectors utilizing quality materials deliver a higher percentage of the available light where it is needed and do this with excellent uniformity. Quality reflectors also have a longer service life. LED technology does not need reflectors to deliver intense light due to advance optics. LED optics also increase the light thumbprint by adjusting beam angles to maximize canopy pentration and light thumbprints.

UNDERSTANDING PAR LIGHT

The McCree Curve represents the average photosynthetic response of plants to light energy. The McCree Curve, also known as the Plant Sensitivity Curve, begins at 360nm and extends to 760nm. This curve can be placed over a spectral distribution chart to see how well a light source can affect plant growth. The quantum response begins at 400nm and extends to 700nm.

McCree Curve PAR plant light photosythetic response

UNDERSTANDING CHLOROPHYLL A and B

Structure - Chlorophyll A and B differ in structure only at the third carbon position. Chlorophyll B has an aldehyde (-CHO) side chain at this carbon position as compared to the methyl group (-CH3) for chlorophyll A. This difference in structure contributes to their varying light absorption properties.

Chlorophyll A - Chlorophyll A is the most commonly used photosynthetic pigment and absorbs blue, red and violet wavelengths in the visible spectrum. It participates mainly in oxygenic photosynthesis in which oxygen is the main by-product of the process. All oxygenic photosynthetic organisms contain this type of chlorophyll and include almost all plants and most bacteria.

Chlorophyll B - Chlorophyll B primarily absorbs blue light and is used to complement the absorption spectrum of chlorophyll A by extending the range of light wavelengths a photosynthetic organism is able to absorb. Both of these types of chlorophyll work in concert to allow maximum absorption of light in the blue to red spectrum; however, not all photosynthetic organisms have the chlorophyll B pigment.

Accessory pigments, the carotenoids, present in many photosynthetic protists, increase absorbance of green light.

chlorophyll a, b andcarotenoids photosynthetic abosorbance

UNDERSTANDING PAR LIGHT vs VISUAL LIGHT

Photosynthetically active radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be damaging to cells and tissues, but are mostly filtered out by the ozone layer in the stratosphere. Photons at longer wavelengths do not carry enough energy to allow photosynthesis to take place.

PAR_plant_light_vs_visual_light_chart

PHOTOSYNTHESIS

Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be later released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis. In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, and such organisms are called photoautotrophs. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth.

Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances such as water, producing oxygen gas. Furthermore, two further compounds are generated: reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP), the "energy currency" of cells.

photosynthesis_plant_light_science_par_light
THE PLANT SCIENCE BEHIND PARMAX™ Professional Series Hybrid LED Pro Panels

PARMAX™ Professional Series Hybrid LED Pro Panels grow lights are much more energy efficient than standard HID (High Intensity Discharge) grow lights, because they produce the correct light spectrum that plants require.   When purchasing a grow light, it’s important to use a light that concentrates energy on the blue and red part of the spectrum, for growth and flowering.  However, don’t disregard the yellow and green part of the spectrum.  Certain spikes in the green and yellow wavelengths  are essential for chlorophyll A and B development as well as the formation of carotenoids, which aid in the process of photosynthesis. During this process, the plant produces energy from light itself. The leaves of each plant possess many functions that all work together to create the energy that is needed to sustain life.

Within the leaves cells is energy producing factories called chloroplasts that hold all the chlorophyll, which are the light absorbing pigments. There are two types of chlorophyll which absorb different spectrums of light: Chlorophyll A absorbs the violet, blue, orange and red spectrum the most. Chlorophyll B absorbs the violet, blue, orange and red as well but absorbs more of the blue that’s closer to the green spectrum. Chlorophyll also absorbs some of the yellow light but not a significant amount. That’s why PARMAX™ Professional Series Hybrid LED Pro Panels grow lightemits just a small measure of the yellow and green spectrum in their LED technology. These grow lights don’t overproduce, which creates wasted energy, but they also don’t under produce. That would also be wasted energy because the plant wouldn’t receive enough to be beneficial. Carotenoids are also light absorbing pigments in the plant, but don’t produce the energy themselves. They must pass that energy onto the chlorophyll which then can utilize that energy. Another benefit that Carotenoids have is the protective properties that are used in protecting the plants cells from elements such as ultra-violet light.

Photosynthesis stages for plant growth

Because light is made up of tiny packets of energy called photons, that energy hits the chlorophyll and is immediately absorbed. This boosts the electrons of the pigment to higher energy levels. Those extra electrons are passed on to molecules of NADP (Nicotine adenine dinucleotide phosphate) and hydrogen to form NADPH, which is used later during the photosynthesis process. However, during this process the chlorophyll gave away too many electrons and is now deficit. To fix this problem, the plant breaks apart water into hydrogen and oxygen stripping electrons from the molecules in the process. Oxygen is then released into the atmosphere as waste and the hydrogen becomes ionized and is pushed through a proton pump where it is used in the bonding of ADP (Adenosine diphosphate) and a phosphate molecule. ADP is essentially the backbone molecule of all metabolisms or the flow of energy in a cell. After the bonding process the new molecules are ATP (Adenosine triphosphate) which is the main transport of chemical energy. This entire process is called the light reaction.

As well as a light reaction, there is also the dark reaction that is also referred to as light independent reactions because this process can happen even in the present of light. This is also referred to as the Calvin Cycle.  During this process the ribulose phosphate, a five carbon molecule, is stimulated by enzymes to convince ATP to give up one of its phosphate groups. Once ATP gives up the phosphate group it becomes ADP, which ultimately will be recharged back into ATP during the light reaction process. That phosphate group is combined with ribulose phosphate to produce ribulose biphosphate, which then joins with water and carbon dioxide.  After the joining of water and carbon dioxide, the molecules become phosphoglyceric acid after it breaks into two identical molecules. Phosphoglyceric acid receives another phosphate from ATP to become biphosphoglyceric acid. NADPH and the hydrogen ion which made earlier are then used to remove the phosphate to provide the energy and hydrogen needed to create phosphoglycric acid or PGAL. PGAL is used to make sugar and replenish the ribulose phosphate stores so this reaction can continue to happen again. 

calvin cycle for plant growth

As long as photons of light continue to be emitted by the sun, photosynthesis will always occur by this revolving process.  Growers using a space with limited sunlight, or where supplemental lighting to the sun is needed, can now use an led grow light that provides the same essential colors of light that will produce healthy, fast-growing plants.  The PARMAX™ Professional Series Hybrid LED Pro Panels offers an energy efficient product that maximizes the correct light spectrum that plants need. Just the right recipe has been achieved to reach this goldilocks zone of the grow light.  All the right light in all the right places.  Not too much and not too little, just right.