With legalization growing across the nation, more cannabis home-growers and indoor grow operations are emerging. One of the most important factors of mimicking sunlight from outdoor-grown cannabis is the lights used for indoor grow spaces. In fact, with the right lights, you’d able to maximize harvests and final yields. So, what are the best cannabis indoor grow lights? And which are the most cost-effective? Let’s discuss.
The Spectrum of Light: An Overview
In order to understand the best cannabis indoor grow lights available for purchase, first, you must understand how light spectrum affects the crops you’re cultivating. To put this idea in perspective, a standard light bulb does not provide sufficient light for the growth of healthy cannabis plants. Remember, when growing, you’re supplying artificial light similar to the sun. So, a light that produces higher wavelengths of light will be required.
Nanometers (NM) are what measure total light output. The output total represents the amount of visible light. Like any standard light bulb, some are ‘cool’, using green or blue portions of the light spectrum to emit their glow. Others are ‘warm’, as they deliver light through the red side of the spectrum.
Regardless of the spectrum color that your bulb emits, on average, the light output from bulbs is 400 – 700 NM. For grow lights, this number increases slightly averaging from 450 – 730 NM. Like a rainbow, red is on the high end of the spectrum near the 730 – 750 NM range. With violet (think ultraviolet) at the lower end near 400 NM.
So, how do you use light output numbers to successfully grow cannabis plants under lights? By knowing that it takes light at 450 NM and 650 NM for a plant to go through photosynthesis. The process where plants use light to synthesize foods, AKA, grow healthily. Meaning, you’ll need lights with the lower or violet spectrum, in addition to the higher or red spectrum too.
In addition, Phytochrome (Pr) is a plant pigment vital in controlling the ability to flower in plants. Light wavelengths of 650 and 730 NM are necessary to activate this pigment, for growing cannabis specifically.
Another way you may see measurements of grow lights’ overall light output, is through lumens. Also known as ‘lux’. Lumens measure the amount of light brightness a bulb emits. But, because cannabis plants require light found outside the spectrum of visible light – lumens or lux identifications, aren’t as accurate as other measurements found on cannabis grow lights.
Types of Grow Lights for Indoor Cannabis Growing
Now that you understand a little more about how indoor grow lights work for cannabis growth, you can have a better idea of how specific light characteristics might help too. Let’s review the most popular types of lights for indoor cannabis growing, and the advantages and disadvantages of each.
Light-emitting diode or LED grow lights are increasing in popularity in the cannabis growing world, being that they’re fairly new on the market. While LED lights are the most expensive grow light option, their various benefits outweigh the initial cost for many cannabis growers.
The biggest difference between LED lighting for cannabis growth, versus other options, is their energy efficiency and minimal heat output-which can help avoid burning when cannabis plants start reaching new heights. Here are a few other pros for LED lights for indoor cannabis grows, and a few cons as well.
LED Grow Light Advantages –
- Plug right in. Other indoor grow lighting sources often require ballasts for proper plugging into electrical outlets. With the majority of LED grow lights, growers are able to use standard electrical outlets for powering up.
- Wide color spectrum. LED grow lights have a wide-range color spectrum, keeping your growth needs covered. LED grow lights are also typically customizable, meaning you can adjust your color spectrum as your cannabis plants reach different growing stages or cycles.
- Supply & ease. The options of LED grow lights on the market are ever-expanding. Not only that, but most growers give LED lights a high score for their overall ease of use.
LED Grow Light Disadvantages –
- Differing strengths. Because of the number of options for purchasing LED grow lights, depending on the brand you choose, the output of your light might not be strong enough for certain phases. Like the flowering phase where increased light output is necessary.
- Extra equipment. Due to the lack of strength found in some LED grow lights, your operation may require extra equipment to bridge the gap. Reflectors are often used to attempt to strengthen the benefits of LED lights.
HID & HPS Grow Lights
High-intensity discharge (HID) grow lights, are unique for the method they use to output light. These large-bulbed systems use the ignition of gas inside the bulb to produce light at a high strength or ‘intensity’. One common type of HID grow light is the metal halides (MH) variety. Because metal halides produce light in the blue spectrum, their function is ideal in the vegetative stage of cannabis plants. Many growers then remove these lights from reflectors and replace them with HPS (High-Pressure Sodium) lights for the flowering stage.
HID grow lights also require a more complex set-up as well. The systems typically include a ballast for electrical hook-up, a bulb, and a reflective hood.
High-Pressure Sodium or HPS indoor grow lights are the most popular option used by growers for the flowering stage of cannabis plants. HPS lights are another type of high-intensity discharge light. Many growers simply swap out their metal halide bulbs for HPS bulbs when entering the stage of flowering their cannabis plants.
The yellow light that is emitted from the HPS bulbs is ideal for cannabis bud growth and production. In fact, HPS grow lights produce the most in yields per watt of electricity in comparison to any other type of light. For example, some growers predict .5 – 1g of flower per HPS grow light watt.
HID & HPS Grow Light Advantages –
- Dimmable. Unlike other grow light options, HID grow lights are often dimmable. Allowing the grower to choose the amount of light output for specific stages of growth for cannabis plants. They can also be installed at appropriate heights, and not lifted or lowered like other grow lights including fluorescents or LEDs.
- Versatile for use. The HID grow light provides optimal spectrums for cannabis plants in their vegetative state. They can also be used throughout flowering, or easily changed to HPS bulbs for additional production. Making them versatile in use, and cost-effective.
- Higher Yields. In comparison to fluorescent grow light options, HID grow light systems are known to produce 2-4 times more in final yields. This is because HID grow lights, produce a higher output of usable light.
HID & HPS Grow Light Disadvantages –
- Diminishing power. Overtime, HID or HPS grow light bulbs can lose effectiveness. Or the power of the light produced is diminished through its’ lifespan. This usually requires growers to keep track of the age of bulbs and swap out when necessary.
- Hot, hot, hot. The biggest disadvantage of HID or HPS grow lights is the heat they produce. Not only can the additional heat burn cannabis plants, but it can also require additional air controllers to keep the growing space at optimal temperatures and humidity levels.
- Ballasts required. Many growers note the amount of equipment that HID and HPS grow lights require as a disadvantage for their overall use. These types of grow lights use additional hardware, including ballasts, to hold the bulb in place. If you’re using two types of bulbs with your HID grow light system, sometimes an additional ballast is required to fit the size or type of bulb, you use for a secondary spectrum.
CMH & LEC Grow Lights
Ceramic Metal Halide (CMH) and Light Emitting Ceramic (LEC) grow lights are a hybrid version of an HID light system. Or, the latest innovation upgrading the benefits of HID and HPS lights. CMH and LEC’s use a metal halide type bulb, with a ceramic arc versus quartz. The unique use of ceramic provides a full spectrum of light, needed for healthy and strong growth in cannabis plants.
LEC’s use a ‘square wave’ technology that helps plants receive more overall light, throughout their lifespan. This results in improved and/or higher yields amongst growers who have implemented these innovative light products.
Their similarities make for comparable advantages and disadvantages to HID and HPS light systems. Here are a few of the pros and cons of CMH or LEC grow lights:
CMH & LEC Grow Light Advantages –
- Most ‘sun-like’. Due to the use of ceramic, CMH or LEC lights burn hot. While this may also be a disadvantage for cooling purposes, it has advantages-like being the most efficient light system in mimicking the energy of the sun. Because the systems are properly insulated, even with the extra heat, the lights protect themselves from potential burning of plants.
- Use for multiple growth stages. The light spectrum provided by the technology of CMH and LEC lights can be used for both vegetative and flowering stages.
- Long-lasting. On average, CMH or LEC bulbs last twice as long as their counterpart bulbs for MH or HPS bulbs used in HID lighting systems.
CMH & LEC Grow Light Disadvantages –
- Special equipment required. A specific type of ballast is required to handle CMH or LEC light bulbs. Only a magnetic ballast can be used, and the lights must be positioned in a specific way. The ballasts cannot be angled but must be hung up and down horizontally.
- UV Dangers. With the amount of work required to maintain a cannabis crop, the UV output of CMH or LEC lights can be worrisome for some growers.
- Cost prohibitive. Being newer to the market, the cost of CMH and LEC grow lights can be cost-prohibitive for some growers. They’re currently the most expensive option of the grow light options on the market.
Fluorescent Grow Lights
Fluorescent grow lights provide another great option for indoor cannabis growing. These lights are measured by their diameter, or ‘T’s’, which is equivalent to 1/8th of an inch. T5 fluorescents are mostly used for early stages of growth in cannabis plants, specifically when growing from seed or clones. Fluorescent grow lights have a purple to white light spectrum making their output ideal for seedlings and clones.
Let’s take look a few advantages and disadvantages of fluorescent grow lights overall:
Fluorescent Grow Light Advantages –
- Affordable. Fluorescent lights are typically the least expensive type of grow light. Used by many hobby gardeners, they are usually readily accessible. The bulbs are also long-lasting, increasing their cost-efficiency.
- Increased coverage. Due to their size, fluorescent grow lights have an expanded coverage area of light output.
Fluorescent Grow Light Disadvantages –
- Restricted use. Fluorescent lights are only used in the early (seed and clone) stage of a cannabis plant’s life. They’re not a suitable option for the vegetative or flowering stages.
CFL Grow Lights
CFL or Compact Fluorescent Lights may look familiar, as they have the same twisted shape that many standard bulbs have now and are purchasable at home and hardware stores. CFL lights are ideal for small spaces and provide an optimal light spectrum for growing cannabis. They’re preferred by growers that are growing a small number of plans (usually 10 or under).
Here are a few of the advantages and disadvantages of using CFL lights for cannabis grows.:
CFL Grow Light Advantages –
- Low Initial Cost. If you’re just getting started in the cannabis growing world, CFLs are a cost-efficient method for grow lights. They’re cheap to purchase and easily accessible available for purchase at hardware and home goods stores.
- Small areas. Growers cultivating in small or short spaces often prefer CFL grow lights. They are ideal for cabinet, cupboard or, small grow tent areas. They also produce low amounts of heat.
- Long-lasting. CFL grow lights are long-lasting and do not require annual replacements like many other grow light options.
- Versatile for use. Many growers prefer CFL grow lights due to their ease of use. They don’t require ballasts and can be plugged into standard light sockets.
CFL Grow Light Disadvantages –
- Less Efficient. CFL grow lights are not as effective for growing multiple plants or as efficient than other grow light options, such as HID or LEDs.
- May require a reflector. Growers who use CFLs often use reflectors to direct as much light as possible towards the cannabis plant in an effort to minimize wasted light.
- Adjustments may be necessary. Keeping a close eye on your cannabis plants is always ideal. But with CFL lights, you might need to make further adjustments to your lights as your plants grow. This includes lifting or lowering the lights, or changing the color spectrum (cool or warm) depending on the stage you’re growing in.
How to Choose the Best Grow lights
So, what’s the best way to choose a grow light for your indoor cannabis plants?
In order to make the best choice be sure to take into account the following factors:
- Stage of growth – Vegetation plants and flowering plants will require different spectrums of light or light strength. To make your decision, take into account your budget for both stages and what works best for your operation, space or amount of plants you plan to grow.
- Size of the room or growing area – Different grow lights and their wattage will cover a varied amount of space and plants which it can efficiently produce light for. Before you choose your grow lights, decide on the amount of space that you’d like to plant in-and don’t forget to measure the height. While most lights are adjustable, it’s easy to burn your plants, as some will require a bigger distance from the plants as they grow. With HPS and LED being the most popular choices for flowering grow lights, here is a quick guide to the space they can typically cover –
250W ≈ 2 plants 120W ≈ 1 plant
400W ≈ 4 plants 200W ≈ 2 plants
600W ≈ 8 plants 280W ≈ 4 plants
1000W ≈ 10 plants 350W ≈ 6–8 plants
- Strain – Cannabis strains all grow differently and produce different results for yields or cannabinoid outputs. Some strains are better for outdoor growth, while some are ideal for indoor growth. Always do your research into the strain you plan to grow to ensure that you get the best lights for your particular strain.
Whether you’re just starting off, or a veteran grower…the right lights are vital for your crop. Big, or small, the spectrum of energy your plants receive will affect their overall growth. Keep this in mind as you experiment with your indoor cannabis grow and make adjustments when or where necessary.