There are a variety of grow lights to choose from and it can be daunting try to choose but we have the tools, information, and expert advice you need to make the choice that’s right for you.
First some definitions
LED: Light-emitting diode
HPS: High pressure sodium
One of the first considerations many new growers think about is heat. LED, LEC™, CDM, and fluorescent grow lights have significantly less heat output than their HID and HPS counterparts. This is very important in a closed growing environment such as a grow tent where this extra energy needs to be managed with air conditioning or ventilation to maintain an ideal temperature for plants to thrive in. HID and HPS lights can still be used with proper ventilation. There are a wide range of options to keep your light from overheating your tent, see which ones fit your needs best. Some models such as Titan Controls offer models that feature high heat shutoffs for certain equipment.
This is a measure of power output and is closely tied to the energy delivered in the lighting footprint. What will your total wattage output be? What type of reflector will you use and will your lights be placed close to the canopy or farther away? All of these considerations come into play in your wattage calculations. The general rule of thumb states that the farther away from the canopy the light is to be placed, the more wattage is required to deliver the same amount of energy to each plant. There is also a cost factor in this equation in that more wattage means higher electricity use which usually leads to more overhead costs of growing. LED and CFL lights are often listed by their equivalent wattage to HID. They draw significantly less power when in operation for the same light output.
Lumens VS PAR
This is the probably the most critical part of the the light buying process. Many different manufacturers throw out a variety of specs when it comes to these two terms but let us break it down for you. Lumens, PAR and Kelvin all refer to spectrums of light. Lumens are generally a measure of the intensity of human visible light while PAR refers to Photosynthetic Active Radiation which is a complex term for the amount of energy released in the spectrum of light ranges that are most useful to plants. Kelvin color temperature classifies light into temperature ranges from "cool" blue ranges to "warm" yellow/gold range. Kelvin temperatures relate to the various colors the sky takes on as the sun moves across the sky from dawn to dusk. 1850K roughly approximates morning sunrise while 6500K is closer to an overcast day. These color temperatures can be useful for understanding the relative color output of a light source. Plants are used to color shifts in light throughout the seasons in order to trigger vegging or flowering. By understanding these light frequency shifts, we can more closely simulate natural conditions and trigger the desired effects in our gardens. LED lights are making tremendous strides in dialing in the exact spectrums plants require for each stage of the growing cycle. Making sure your light choice matches what you need your plant to do, be it vegetate or flower, will greatly improve your growing process and results.
This is really just a measurement of how much area the light covers. The critical things to keep in mind here are the reflector shape, size and distance from the light to the plant canopy. The farther away a light is placed from the plant canopy, the larger the light footprint it will be and the less energy that will be delivered per square unit to the plants. The light loss factor diagram below illustrates this principal. For every foot farther away the light is placed, there is a 25% reduction in light intensity. The light footprint also expands with each foot the light is raised.
LED lights have recently made tremendous progress in the past few years making them a great option for most tent growers. They are some of the most popular lights on the market today. The cost benefit from the energy savings quickly outweighs the higher initial cost. Utilizing high-quality light-emitting diodes, today's LED grow lights are durable and produce broader and more adjustable light spectrums more optimized for plant growth. Producing very little heat, LED lights are a great option for grow tents and smaller grow rooms where heat and ventilation is a concern. They are also great for large operations as well. Because LED lights are one-piece units, they are very easy to set up and hang. At Hydrobuilder we highly recommend LED lighting for most growers.
• Simple to setup and operate
• Offer lower operating costs
• Produce very little heat
• Can be placed close to the plant canopy
• Some offer an adjustable spectrum
• Higher initial cost
• Lights need to be turned off to inspect the plants or users should wear corrective glasses
• Can weigh more than other lights
LEC lights produce very little heat but tons of usable light. Because the light spectrum is broader than typical HID lights, they produce more optimal light that plants can utilize (a higher PAR value) throughout the various stages of plant growth. Though typically having a higher initial cost than HID lighting, LEC™ lights quickly pay for themselves in the long run with the energy savings and the rate at which plants grow with them. Long bulb life also saves you time and money. LEC™ lights are a good choice for small to large grow tents and for added performance, paired with LED light bars. LEC lights are available in various spectrums from 2000K to 4200K as well as a range of voltages.
• Low Heat
• High output
• long bulb life
• Smaller light footprint
• Often need to be paired with supplemental HID lighting
These lights are a popular option for many growers due to their low price, energy efficiency, and low heat output. Induction lights are very similar to fluorescent lights except instead of electricity flowing between wire connections inside the lamp, the electricity is regulated by a high frequency generator from wires outside the lamp, from one side of the bulb to the other. There are many sizes available that utilize different size fluorescent tubes. "CFL" or compact fluorescent bulbs are also available and are even more efficient than standard fluorescent tubes. Because of the low heat and lower intensity, fluorescent lights can be placed extremely close to plants and are a great option for young plants that benefit from the less intense light. Fluorescent tubes come in various spectrums allowing you to select the optimal spectrum for various stages of growth. If you are growing mothers or clones fluorescent lighting is a great option. Some growers do choose to use fluorescent lights for the entire growth cycle but this is not optimal for plant development.
• Energy efficient
• Very low heat output
• Does not transmit as much light energy as other light sources
HID has been the standard for decades in the growing industry. Pumping out tremendously intense light, the watt to lumen ratio for HID lighting is among the highest for all types of lighting. HID lights also pump out lots of heat and may need to be cooled for tents. Because of the heat and light intensity, the lights must be kept at a sufficient distance from the plant canopy to avoid burning the plants and leaves. Bulbs must be replaced often to ensure optimal spectrums are maintained, typically bulbs last 1 - 2 years.
HID lighting comes in many different wattages to accommodate different garden needs. The total wattage of a HID lighting system determines its intensity and the number and quality of the plants that it can grow. The more watts, the more intense the light. At Hydrobuilder.com we offer HID lighting from under 65 Watts all the way up to 1000 Watt lights.
HID lighting requires three components, all of which can affect the light output and performance of the lighting so it is crucial to understand how each part works together to achieve optimal lighting.
HID lighting utilizes ballasts to amplify and regulate the frequency of the energy used to power the bulb. Typically these ballasts are a separate unit from the bulb socket and hood. There are two main types of HID ballasts, magnetic and digital. Magnetic ballasts are less expensive but can run hotter, are heavier, and must be paired to the type of bulb you plan to use (though switchable magnetic ballasts are available. Digital HID ballasts are preferred for their smaller size and lower weight, their energy efficiency, lower heat output and durability. Dimmable digital ballasts are also available allowing you to use one ballast for a number of bulb wattages. Some ballasts also offer remote control and can be chained together for better control of an entire room full of lights.
There are three main types of bulbs used in HID lighting: High-Pressure-Sodium or "HPS," Metal-Halide or "MH," and Double-Ended High-Pressure-Sodium or "DE." There are also "conversion" bulbs that allow you to use a HPS bulb with a MH ballast, or visa versa. "Dual Arc" bulbs contain both HPS and MH arc tubes offering a broader spectrum.
MH bulbs produce light with more wavelengths in the blue part of the visible light spectrum and are typically used for vegetative growth. HPS bulbs produce more red light and are optimal for the flowering period of the growth cycle. Double-Ended HPS bulbs require compatible ballasts and reflectors but produce more intense light and run more efficiently.
There are many shapes and sizes of light reflectors available and each produces a different light footprint and other benefits. "Air-Cooled" and "Cool Tube" reflectors allow you to run ducting and pump air over the bulb to help with the removal of heat from your grow tent and are typically sealed with glass. "Open" reflectors come in various shapes such as "wing," parabolic, and rectangular. Double-Ended HID Lights require compatible reflectors. HID lighting can also be run without a reflector by mounting the bulb and socket directly from the ceiling of a grow tent.
• High intensity light
• Great watt-to-lumen output ratio
• High heat output
• Bulbs must be replaced routinely
Questions or want help building a custom lighting system for your grow tent? Give our experts a call at 888-815-9763 or email [email protected].
Patten, G. F. V. (2008) Gardening Indoors With Soil & Hydroponics. China. Van Patten Publishing