When choosing a grow light it is extremely important to remember that light is as important as water to your plants. It helps them produce chlorophyll and supports photosynthesis. Growing outside in natural sunlight plants receive a “full-spectrum” of light. Reds and blues are the colors at the ends of the spectrum that are key to plant health. Blue light directly affects chlorophyll production, creating strong leaves and stems. Red light is responsible for fruit and flower production and is especially important in the beginning stages of plant growth - seed and root development. Indoor growers seek to create a varied spectrum of lighting as optimally as possible to support their plants at different stages of growth. It’s all about choosing the right lighting for your grow.
There are many grow light choices available and several things to consider when you're choosing a grow light. Some of the things you need to consider are: Which one is best for you? Start off by considering a few key things such as your overall operating budget. How much money are you prepared to spend, both in the initial investment, and then the day to day operation? How much area are you lighting? How long will your lights be used? Are you planning a year-round garden? Will you have a perpetual (clone, veg, and flower) grow? What kind of plants are you growing?
As you can see, you need to put some thought into choosing a grow light.
This is a breakdown of some of the most common lighting options available and by no means a complete list of everything out there. We will discuss the different lighting types, their uses, and their pros and cons to help you narrow the field and determine which one is best for you.
T5 Fluorescent Tubes
This type of lighting is best for seedlings, clones and small plants, they run cool.
T5s typically come in two different lengths, 2 and 4 foot, and have 1, 2, 4, 6, 8 or 12 bulb fixture configurations. Obviously, if you’re growing a few small plants, you’ll be able to use a smaller set up (shorter length, 1 or 2 bulb fixture).
Color temperature is also a factor you’ll want to consider. As a general guideline when plants are in the vegetative stage use a 6500K bulb, which emits a bright light like on a summer day. In the flowering stage use a 3000K bulb, which is more like the light at the end of the day - sunset.
- Less expensive than most other types of grow lights.
- Covers a large area of lighting.
- Longer life in comparison to other types of light (+20,000 hours with very little decrease in efficiency).
- Runs cool. eliminating the need for ducting and ventilation.
- Not as effective in the vegetative and flowering stage as the other types of lights.
High-Intensity Discharge (HID)
This is a category of lighting that includes: Metal Halide (MH), High-Pressure Sodium (HPS), Double-Ended (DE), and Ceramic Metal Halide (CMH) lamps. These lights require a reflector/fixture, a ballast, and a lamp (often referred to as a bulb). These components are sold separately or purchased as a kit. Buying as a kit ensures compatibility. These lights emit the brightest light and produce high amounts of heat.
One of our favorite ballasts is the SolisTek 600/400W SE/DE Digital Ballast 120/240V.
- Lamps are dimmable in many instances so you can regulate and customize your lighting.
- A digital ballast will operate many types of HID lamps.
- Life span of these bulbs can range between 10,000-24,000 hours depending on the type.
- Produces much more usable light than a fluorescent.
- Lamps produce high heat - you’ll want ducting and ventilation.
- Higher energy costs.
- Requires additional equipment. Ballast and reflector. You may need different ballasts with different types of lamps (MH and HPS).
- Lamp effectiveness and efficiency lessen over time.
Metal Halide (MH)
- Emit a high output/high quality of light on the blue end of the spectrum (like hot summer sun).
- Especially effective in the vegetative stage in plant development.
- Lamps themselves are relatively inexpensive.
- Shortest life span of all HIDs at 10,000-20,000 hours.
- Do not emit the red portion of the light spectrum that plants need to flower. Plants may still flower but the yield will not be as high.
- Burn hot.
- Quality and quantity of the light lessens with use.
High-Pressure Sodium (HPS)
- Emits light on the red end of the spectrum (like in the fall), triggering the flowering stage of plant
- Life span somewhat longer than MH at 12,000 - 24,000 hours.
- No emission of the blue light that plants need in the vegetative stage of development
- Burns hot
- Quality and quantity of light lessens with use
If you are growing plants that flower and fruit you may want to use MH and HPS together to get the benefits of the full-range lighting.
DE lighting is a type of HPS that has come onto the market in the last few years. It connects to a ballast at each end (kind of like a fluorescent tube), unlike the single-ended (SE) HPS mentioned above. As with all HIDs, you need to ensure that the reflector/fixture, ballast, and lamp are compatible.
- DE lighting has a longer life span and remains efficient longer than the single-ended HPS. Although the SE loses much of its efficiency around 10,000 hours, DE can retain as much as 90% of its efficiency at that same age.
- Because DE lamps are thinner, they cast more light over the grow space than SE lamps at the same height. This makes their use more efficient in terms of lighting and energy use.
- Emits more ultraviolet and infrared light than SE which, for some plants, increases potency and oil production.
- DE lighting produces more heat than SE lighting, leading to possible heat damage to plants.
- DE lighting does not tolerate direct contact with air blowing from circulation fans. It will cause a decrease in efficiency.
Ceramic Metal Halide (CMH) or Light Emitting Ceramics (LEC) [used interchangeably]
We offer complete CMH fixtures such as the SolisTek C2+ 630W Dual CMH Complete Fixture 120/240/277V is a fantastic complete fixture which is controller ready, guarantees high output & consistent spread, has incredible PAR output which replaces 1000W HID systems and comes with 2 x SolisTek CMH lamps.
Additional CMH grow lights can be found here.
- Life-span is twice as long as MH or HPS.
- Energy efficiency. Costs less to run. Some areas offer incentives to offset purchase costs because of the energy efficiency rating.
- Burns hotter than MH, emitting light more like natural sunlight but has an insulating value that decreases the heat output which is less likely to burn plants than MH and HPS.
- Light quality supports both vegetative and flower stage of plant growth. Both UV and infrared rays creating light close to that of natural sunlight.
- Steadier beam. Plants receive more light.
- Less electromagnetic interference (EMI) than with other digital ballasts because of the special ballast required to run them.
- Only magnetic ballasts can be used.
- Positional. They cannot be placed on an angle. They can only vertically or horizontally.
- Protection is needed from the UV light. Wear long sleeves and protective sunglasses, or work during a dark cycle with the use of a green LED headlamp.
Light Emitting Diodes (LED)
Light Emitting Diode (LED) grow lights are a type of energy efficient lights that are an option for indoor growers. Unlike other types of grow lights, LEDs do not burn a filament but instead pass light through semiconductors to create their spectrum. LED grow lights can be used as the sole means of lighting your grow, as a supplement to natural light, or paired with other types of grow lights.
Unlike other types of grow lights, light emitted by LEDs can be focused, so no light is dispersed or lost between the bulb and the canopy of the plants.
We offer several LED grow lights and are adding new ones all the time. Click here check out our LED grow lights.
- Long life-span. They can last over 50,000 hours.
- Energy-efficient. Cheap to run.
- Generally, produce more light per watt than fluorescents and HIDs.
- Run cool. Produce little to no heat.
- Good for small growing spaces.
- No ballasts required. Just plug into standard outlets.
- Spectrum of light is wide and customizable depending on your growing needs.
- Wide array of lights with many features and benefits available on the market.
- Considered the easiest light to grow with.
- Cost. The purchase price is much higher compared to other lighting choices.
- May not emit as much light as expected. Always make sure the emitted light is at least 2.0 micromoles/watt of energy.
- May not be effective for the flowering stage (depending on the manufacturer). Do your research based on what you are growing.
Bottom Line: When choosing a grow light consider what you are growing, your growing needs, the space you are growing in, and the budget you are operating within. There’s quite an array to choose from today.