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Choosing Your Grow Lights

There are many lighting options available on Hydrobuilder.com and each offers unique benefits that can help you achieve your goals. Some factors that differ between the various types are: heat output, energy use, bulb or lamp life, price and the recommended height the light should be placed away from the plant canopy.

Choosing Your Grow Lights


Types of Grow Lights

HID (HPS/MH)
Lights
CMH or LEC©
Lights
LED
Lights
Fluorescent
Lights

 

There are many lighting options available on Hydrobuilder.com and each offers unique benefits that can help you achieve your goals. Some factors that differ between the various types are: heat output, energy use, bulb or lamp life, price and the recommended height the light should be placed away from the plant canopy. For example certain high intensity lights require at least 48” of space from the top of your plants canopy to the bottom of the light. Growers with short ceilings may find this type of light prohibitive.

High Intensity Discharge (HID) Grow Lights

HID Lighting

 

Best For:

  • The average grower with a typical grow room setup
  • Grow rooms that can properly ventilate the heat produced

Pros:

  • High intensity light
  • Great watt-to-lumen output ratio
  • Inexpensive

Cons:

  • High heat output which must be vented or cleared from the room
  • Bulbs must be replaced routinely (every 9 - 12 months)

HID, or High-Intensity-Discharge Lighting, 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 some gardens. 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 9 - 12 months.

HID lighting comes in many different wattages to accommodate different garden needs. The total wattage of a HID lighting system determines it's 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 250 Watts all the way up to 1000 Watt lights.

HID lighting requires three components; a bulb, a ballast which turns the bulb on, and a reflector or ‘hood’ that throws the light into a certain area. 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 Grow Light Ballasts

Grow Light Ballasts

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.

 

HID Grow Light Bulbs

Grow Light Bulbs

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.

 

HID Grow Light Reflectors

reflectors

There are many shapes and sizes of HID 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 room 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 room, or hanging them.

Reflectors and lighting technology are constantly improving and a small increase in efficiency can pay for itself tenfold over the course of a year or two. But does it really make a difference what you spend? The short answer is yes, in the right situation. Your grow room is like any other system—it’s a chain that is only as strong as its weakest link. If temperature, humidity, CO2, nutrient strength, pH and watering frequency are all dialed in, then optimizing photosynthetically active radiation (PAR) will correspond with an increased yield and a better quality product. However, if you buy the most expensive lighting system on the market, but don’t give your plants the resources they need you will end up with small yields of low-quality product. Many factors determine how PAR is distributed over an indoor canopy: grow lights, the type of ballast and reflector, spacing between lights, and distance from the canopy.

Grow Light Loss Factor

 

In order to understand light distance and spacing, you have to consider the inverse-square law. In physics, the inverse-square law of light states that a specified quantity or intensity of light is inversely proportional to the square of the distance from its source. What does that mean for indoor growing? A given amount of light doesn’t diminish at a greater distance from its source; it spreads out into a space that is equal to the square of that distance. At two feet from its source, light is spread out over four square feet and is therefore one-quarter its intensity at one foot from its source. For simplification, we call one foot from source, “original intensity.” This is important to understand when selecting reflectors. If you hang a single light with no reflector in the middle of a room with black walls, the intensity of the light available to the canopy will diminish by the square of the distance between the light source and the canopy. Many reflectors are designed for this situation. They focus as much light as possible into a small area so they can be hung high enough above the canopy to control heat while producing enough light intensity to grow plants. In this case, it efficient than using a reflector that is designed to spread light out as much as possible. One standard 1000 watt HPS light is sufficient for 16 to 25 square feet of canopy area. A reflector that focuses the light should be used if there are no other lights in the grow room. Reflective material should also be hung around a 4’ by 4’ or 5’ by 5’ area.

In a room that has many lights, the area that each light shines on overlaps. This means that at five feet between canopy and bulb, the light is spread out over 25 square feet at 1/25 the original intensity. But if there are lights hung in a grid 5 feet apart from each other, the overlapping spread from each bulb will increase the light intensity in any given square foot of canopy by the square of the distance between each bulb and that part of the canopy. The amount of light hitting any one particular square foot of canopy can also be increased significantly in this situation by hanging reflective material around the perimeter of the canopy area.

light-overlap

Reflectors that are designed to spread light out over a large area are ideal in this situation because they create a much more uniform spread than reflectors that are designed to focus light in a small area. The distance between canopy and bulb is much less important in a situation where many lights are overlapping each other and reflective material is hung around the perimeter of the canopy. In this situation, light intensity could be exactly the same at three feet and ten feet between canopy and bulb. In practice, light intensity does diminish somewhat at greater distances because no material is able to reflect 100% of the light back into the canopy. Many growers who use multiple lights in this way produce great results hanging their lights at ceiling level from start to finish.

Here are some reflectors tips:

  • A reflector that is designed to focus light in a small area should be used in a situation where reflective material cannot be hung around the perimeter of the canopy area.
  • A reflector that is designed to spread light out will create more uniform lighting in a situation where many lights are overlapping each other.
  • Reflective material should be hung as close to the perimeter of the canopy as possible.
  • Distance between canopy and bulb is much more important in a situation where reflective material cannot be hung around the perimeter of the canopy. Lights should be as close to the plants as possible without burning them. This means the temperature of the canopy should never be consistently above 80 degrees Fahrenheit.
  • Distance between canopy and bulb is much less important in a situation where many lights overlap each other and reflective material is hung around the perimeter of the canopy.
  • 1000 watt HPS lights are hung in a grid four to five feet apart and 600 watt HPS lights are hung three feet apart. Yield per watt can be increased by spreading lights out. Yield per square foot can be increased by hanging lights closer together, especially if CO2 is supplemented.

 

Ceramic Metal Halide (CMH) & Light Emitting Ceramic (LEC®) Grow Lights

LEC Lighting

Best For:

  • Growers of all experience levels
  • Commercial grow operations are beginning to use these more and more
  • Grow rooms in high-heat environments

Pros:

  • High Lumen and PAR output
  • Energy efficient
  • Very low heat output - can place close to plants
  • Long bulb life
  • The BEST choice for most applications

Cons:

  • Smaller light footprint than some of the HID counterparts… But with the smaller electricity bill this is typically not relevant.

Ceramic Metal Halide (CMH) & Light Emitting Ceramic (LEC®) Grow Lights grow 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 throughout the various stages of plant growth. Though typically more expensive 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. We recommend LEC lights for small to large grow rooms or as supplemental lighting paired with HID. Because the light is more focused supplemental lighting is suggested. Learn more about why the Sun System LEC Grow Lights are our favorite.


 

LED Grow Lights

led-lighting

Best For:

  • Growers of all experience levels
  • Commercial grow operations are beginning to use these more and more
  • Grow rooms in high-heat environments

Pros:

  • High intensity light, adjustable spectrums on some models
  • Extremely energy efficient
  • Long life - no need to replace bulbs

Cons:

  • High initial cost

LED grow lights have recently made tremendous progress in the past few years making them a great option for most growers. Though expensive, the cost benefit from the energy savings quickly outweighs this increase in 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 setup and hang. At Hydrobuilder.com we highly recommend LED lighting for most growers.


 

Fluorescent Grow Lights

Fluorescent Grow Lights

 

Best For:

  • Vegetative growth, young plants, and mother plants
  • Grow rooms in high-heat environments
  • Growers on a budget

Pros:

  • Energy efficient
  • Inexpensive
  • Very low heat output - can place close to plants

Cons:

  • Not as intense as other options

Fluorescent lighting is a popular option for many growers due to it's low price, energy efficiency and low heat output. There are many sizes available that utilize different size fluorescent tubes. Typically growers use T5 or T8 bulbs, which come in various lengths. "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. Many growers do choose to use fluorescent lights for the entire growth cycle as well with great results.


How to hang your grow lights

hang

To hang a light in a room with a drywall ceiling you will need to either use hooks with drywall anchors or screw something into the ceiling joists to attach lights to. If you use drywall anchors, make sure they are rated for the amount of weight you hang from them. Two standard plant hooks from the hardware store are generally sufficient for each light. If you’re hanging several lights in a row or you’d like to minimize damage to your ceiling, you may want to attach a two-by-four to the ceiling joists with screws where you would like the center of your row of lights to be. You can find and mark the joists with a stud finder. If the center-line runs parallel to your ceiling joists, you will need to either attach the two-by-four using heavy-duty drywall anchors every few feet or span two joists with a short piece of two-by-four every few feet and attach the centerline piece to that. You can then screw hooks into the center-line two-by-four to hang lights. Lights can be attached using standard s-hooks.

Once you have a structure to hang your lights from you will need to decide if you will be raising and lowering them. Check out light distance and spacing. If you want to be able to raise and lower your lights, there are several products designed for this purpose. If you only have a light or two and they are accessible during your growing cycle, something as simple as chains with s-hooks could work. The lights can be raised as your plants grow taller by attaching the s-hooks to progressively higher chain links. Another convenient option is the rope-and-pulley system, you can raise and lower lights from across the room. Especially useful, if part of your grow room is not accessible during the growing cycle. Some growers use thicker ropes and larger pulleys to raise and lower an entire row of grow lights at once. Automated systems use dual motorized spools of string that can be controlled with a remote from up to 30 feet away. A remote can control up to eight lights. If you’re setting up in a warehouse with high ceilings, it may not be practical to hang your lights directly from the ceiling. Commercial growers often create structures to hang lights with strut channels hung from roof trusses or ceiling joists.

The main thing you want to keep in mind is that whatever you use to hang lights needs to be anchored well and strong enough to support the weight of the lights you’ve chosen. Some reflectors are light enough to hang with string while other lights will require chain or heavy gauge rope. Larger banks of LEDs or double-ended HPS systems that have a ballast attached to the reflector can be fairly heavy. Always err on the side of caution and overestimate your need for stability.

 



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