Which Grow Light Should I Use For Growing Cannabis?

Marijuana plants are delicate things – they require a great amount of care and monitoring throughout their growth. While the weed that grows in nature doesn’t require such care and monitoring, this is more of an indoor growth thing. A large number of people who grow their weed indoors need to take special care of their marijuana plants.

Grow lights are essential for indoor growth of marijuana plants because they act as an artificial source of light as well as heat. Basically, they are a replacement for sunlight, which provides light and heat to the marijuana plants when they grow outdoors. Grow lights are among the most important tools needed when it comes to growing marijuana plants indoors. While there are a number of grow lights available in the markets – you need to ensure that you are buying a grow light which suits your needs.

Let us now take a look at the different types of lights that are available in the market for your indoor marijuana farm:

Fluorescent Grow Lights (CFL, Tube lights)

Fluorescent lights are well known for their efficiency. They will not penetrate with great intensity but they are an amazing option for anyone who is concerned about the electrical usage or the temperature control.

Because of the fact that these lights will not penetrate the buds with intensity, the resulting buds will be fluffy and relatively small when compared to the dense beauties available at the dispensaries. In order to make up for their relatively poor penetration, the lights will have to be kept within 3” of the plant and more than one light will be needed in order to cover the whole plant.

The fluorescent bulbs are available in the market from a few dollars to a few hundred dollars and might require a customized fixture as well.

Light-Emitting Diodes (LED)

In the recent years, LEDs have gained massive popularity among growers as they do not require any sort of extra components, are extremely energy efficient, are available in each and every spectrum of colors and are cool enough to touch and move around without burning yourself.

LED lights cover only a small space of area so you might want to consider buying them in bulk and they are less intense which might result in having less dense and smaller buds. Most of the professional growers use LEDs with High-Density Discharge lights in conjunction in order to produce high-quality dispensary-like buds for a relatively lesser cost.

The average LED lights can be purchased in the markets for around a hundred dollars to a thousand dollars. Make sure to check if the LED light is suitable for growing at the time of purchase as not all LEDs are capable of growing indoor marijuana.

High-Intensity Discharge lights

A favourite among the professionals, these High-Intensity Discharge lights will give you dense and big buds every single time. However, these bulbs are bound to get very hot and as a result, you will need to install a ventilation system or a temperature control system in order to keep the temperature under control.

These bulbs need to be replaced after certain intervals of time which makes the High-Intensity bulbs an ongoing investment. The setup or the HID bulbs can cost from a few hundred dollars to more than a thousand dollars

Growing cannabis with LED is becoming a mainstream alternative to HPS. Although the initial purchase cost of an LED is still higher than an HPS, the ongoing running costs are lower. LED produces less heat than HPS and this affects many aspects of plant maintenance and grow room design.

LED lights usually produce much less heat than a HPS light of comparable productivity.  The lower heat levels from a LED means the leaves of a cannabis plant generally transpire (evaporate) less moisture under LED compared to HPS. 

The transpiration differences mean that Calcium and Magnesium ions can be less mobile under LED and this may cause deficiencies that you will have to correct with nutrient additions. 

You may not notice this issue since soil (and many grow nutrients) already contain adequate levels of Calcium and Magnesium.  Calcium/Magnesium supplemental nutrients are widely available in any grow shop.

LED power levels have been increasing significantly over recent years, and at the same time so have the LED efficiencies.  Early LED’s would convert 15% of electrical energy to light energy, now the best LEDs convert over 50% of electrical energy into light and that figure is rising. 

When light levels are too intense the tips of the plants are bleached, they look white instead of green.  This can be a sign to raise the LED lights higher, or to tie down the tallest branches of your plants.  

ThinkGrow Model-H 630W Horticulture LED Grow Light

The Model-H is a high performance LED grow light for the horticulture cultivation. It is designed specifically for high PPFD cultivation practices in vertical farming. Full spectrum design with spectral tuning capabilities cover each critical phase of growth from vegetative to flowering.

ThinkGrow is brought to you by the same company making TrolMaster controls -- currently one of the most sophisticated digital environmental controls on the market. ThinkGrow LED lights are also fully compatible with TrolMaster controllers with up to 256 lights being able to be controlled per digital channel.

Fluence SPYDRx PLUS LED Grow Light

SPYDRx PLUS is designed for full-cycle commercial cannabis cultivation with the power to scale from vegetative growth to bloom. For optimal results, we recommend CO2 supplementation between 800-1400 ppm due to high PPFD levels. Also designed to cover a 4’x4’ area at only 6 inches above canopy, SPYDRx PLUS delivers an average of 1030 µmol/m2/s of light over your crop with unparalleled uniformity.

ECO Farm GLT 500 Dimmable Samsung LM301B Grow Light

• Using highest Samsung output LEDs, Efficacy is up to 2.6umol/J.


• 1524 high PPFD in 12 inches.


• Full spectrum with enhanced red for full cycle grows.


• The beam angle of light bars are adjustable easy to install.


• Extra 50Watt bar can be added in the middle of the fixture to provide more Far red UV light.


• Supporting RJ port daisy chain and 0-10V dimming knob.


• ETL&cETL, DLC, CE, ROHS certified product.

Kind LED X² Commercial LED Grow Light

Developed as the perfect solution to vertical racking and overhead grow operations, the X² commercial LED grow light from Kind LED was specifically designed for close-proximity growing, capitalizing on valuable tiered growing space while maintaining a large coverage footprint and tremendously even PPFD output. This means increased harvest weight and quality, and unmatched potential for financial returns at harvest. Discover the future of commercial LED grow lights today!