LED Grow Lights

Grow lights are artificial light sources that provide the optimal spectrum and intensity of light for plant growth.  Grow Lights can be used to supplement natural sunlight or to replace it entirely, depending on the type and stage of the plant.  See the guide on why LED grow lights that use the latest in full spectrum light coverage ensure healthy and productive plants with robust growth.

There are several factors to consider when using grow lights, such as:

•  Intensity: This is the amount of light that reaches the surface of the plant, measured in lumens or lux. The intensity of the light affects the photosynthesis rate, the biomass production, and the morphology of the plant. Different plants have different light intensity requirements, depending on their natural habitat and adaptation. Generally, plants that are native to sunny regions need higher light intensity than plants that are native to shady regions. The intensity of the light can be controlled by adjusting the brightness of the bulb and the distance between the bulb and the plant.

•  Duration: This is the number of hours of light that a plant receives in a 24-hour period, also known as photoperiod. The duration of the light affects the flowering and fruiting of the plant, as well as its circadian rhythm and metabolism. Different plants have different photoperiod requirements, depending on their natural seasonality and response to day length. Generally, plants can be classified into three groups based on their photoperiod response: short-day plants, which flower when the day length is shorter than a critical value; long-day plants, which flower when the day length is longer than a critical value; and day-neutral plants, which flower regardless of the day length. The rule of thumb is to provide grow lights for about 16 hours per day, so that the plants can have about 8 hours of dark. During the dark period, many plants are able to use some of the energy from the light to grow. In fact, the dark period is essential for plant growth and development.

•  Color: This is the wavelength or frequency of the light, measured in nanometers or Kelvins. The color of the light affects the pigmentation, the photosynthesis efficiency, and the photomorphogenesis of the plant. Different plants have different light color preferences, depending on their natural spectrum and adaptation. Generally, plants use more light from the blue and red parts of the spectrum than from the green and yellow parts. Blue light (400-500 nm) stimulates vegetative growth, such as leaf and stem development, while red light (600-700 nm) stimulates reproductive growth, such as flower and fruit formation. Color temperature, which is measured in Kelvins, indicates how warm or cool a light source appears. A higher color temperature means a cooler or bluer light, while a lower color temperature means a warmer or redder light. For example, a 5000 K light is a cool white light, while a 2500 K light is a warm white light. Typically, cool white lights are good for vegetative stages, while warm white lights are good for flowering and fruiting stages.

When in doubt, go full spectrum. Recent research has shown that full spectrum light is best for all kinds of growing, particularly with lights for growing cannabis. This is not surprising since the sun is the most full spectrum light source there is. Full spectrum light contains all the wavelengths that plants need for photosynthesis and photomorphogenesis. Choose an R9>70 and CRI>90 for best results. R9 is a measure of how well a light source renders red colors, which are important for plant health and appearance. CRI is a measure of how well a light source renders all colors, which are important for plant quality and identification.

PAR stands for photosynthetically active radiation, which is the range of wavelengths that plants use for photosynthesis (400-700 nm). PAR is a better way to measure light for plant growth than lumens or lux, which are based on human perception of brightness. PAR indicates how much usable light a plant receives for photosynthesis, which determines its growth rate and yield. PAR can vary depending on several factors, such as seasonality, latitude, time of day, cloud cover, shade, air pollution, etc. Generally, PAR levels are highest during midday in summer at low latitudes, and lowest during early morning or late afternoon in winter at high latitudes.

PAR is important because it is essential for plant growth. Higher PAR levels promote plant growth, while lower PAR levels limit plant growth. Monitoring PAR levels is crucial to ensuring that a plant receives adequate light for its needs and preferences.

CRI, or color rendering index, is a numerical measure of how well a light source can reveal the colors of various objects in comparison with a natural or ideal light source. CRI is calculated by comparing the appearance of eight standard color samples under a test light source and a reference light source, and then averaging the differences. CRI ranges from 0 to 100, with 100 being the best possible score. Natural light sources, such as sunlight or incandescent bulbs, have a CRI of 100, meaning they render colors most accurately. LED lights, which are artificial light sources that use light-emitting diodes, can have varying CRI values depending on their quality and design. Generally, LED lights with higher CRI values are preferred for applications that require accurate color perception, such as photography, art, retail, or medical settings.

However, CRI is not a perfect indicator of color rendering performance, as it has some limitations and drawbacks. One of them is that CRI only considers eight color samples, which are mostly pastel colors and do not represent the full spectrum of colors that exist in nature. Therefore, CRI may not reflect how well a light source can render other colors, especially saturated or vivid colors. This is where R9 and R13 come into play. R9 and R13 are two additional color samples that are used in the extended CRI calculation, which includes 14 color samples in total. R9 is a deep red color, while R13 is a skin tone color. Both of these colors are important for many applications that involve human subjects or red objects.

R9 and R13 are often reported separately from the general CRI value, as they can provide more information about the quality of a light source. R9 and R13 values can range from -100 to 100, with higher values indicating better color rendering. A light source with a high general CRI value may still have a low R9 or R13 value, meaning it cannot render red or skin tones well. Conversely, a light source with a low general CRI value may still have a high R9 or R13 value, meaning it can render red or skin tones well. Therefore, it is advisable to look at both the general CRI and the R9 and R13 values when choosing a light source for your specific needs.

Another factor to consider when choosing a light source is the spectrum or the distribution of wavelengths that it emits. The spectrum of a light source affects its color temperature, its efficiency, and its impact on plant growth. Color temperature is a measure of how warm or cool a light source appears to the human eye, expressed in Kelvins (K). A higher color temperature means a cooler or bluer light, while a lower color temperature means a warmer or redder light. For example, daylight has a color temperature of about 5100 K, while candlelight has a color temperature of about 1800 K. The color temperature of a light source can affect the mood and ambiance of a space, as well as the visual comfort and productivity of the occupants.

Efficiency is a measure of how much light output a light source can produce per unit of power input, expressed in lumens per watt (lm/W). A higher efficiency means a more energy-saving light source. The efficiency of a light source depends on its spectrum and its technology. Generally, LED lights are more efficient than incandescent or fluorescent lights, as they convert more electricity into visible light and less into heat. However, not all LED lights have the same efficiency, as some wavelengths are easier to produce than others. For example, blue LEDs are more efficient than red LED. The spectrum of an LED light can be adjusted by using different types of phosphors or combining different colors of LEDs.

The impact on plant growth is another aspect of the spectrum of a light source that is relevant for indoor gardening or farming applications. Plants use light for photosynthesis and photomorphogenesis, which are processes that involve converting light energy into chemical energy and regulating plant development respectively. Plants have different responses to different wavelengths of light, depending on their pigments and photoreceptors. Generally, plants use more blue and red light than green and yellow light for photosynthesis. Blue light stimulates vegetative growth such as leaf and stem formation, while red light stimulates reproductive growth such as flower and fruit productionhttps://www.ledgrowlightsdepot.com/. However, other wavelengths may also have important roles in plant growth regulation.

Full spectrum is a term that is often used to describe light sources that emit all wavelengths of visible light in similar proportions to natural sunlight. Full spectrum light sources are considered to have high CRI values and high R9 and R13 values, as they can render all colors accurately and vividly. Full spectrum light sources are also considered to be beneficial for plant growth, as they can provide all the wavelengths that plants need for photosynthesis and photomorphogenesis. However, there is no standard definition or measurement of full spectrum, and different light sources may claim to be full spectrum based on different criteria Therefore, it is important to look at the actual spectrum of a light source, rather than relying on the full spectrum label alone.

In conclusion, CRI, R9, R13 and full spectrum are some of the terms and concepts that are used to describe and evaluate the quality and performance of light sources. They can help you choose the best light source for your specific application, whether it is for human or plant use. However, they are not the only factors to consider, as there are other aspects such as intensity, duration, dimming, cost, and durability that may also affect your decision. Therefore, it is advisable to do your research and compare different options before purchasing a light source for your indoor space.