Growing indoors grants you a ton of opportunities to optimize the environment for peak plant health and the greatest yield. The type of grow lights which you use will affect the growth of your cannabis on more levels than you’d expect.
While most growers agree that 1 gram of cannabis per watt is a good target, not all lighting is equal. Halogen pressure sodium (HPS) lighting are the bulbs most commonly used for grow lights but LED technology is beginning to surpass the trend.
With equal or better yields in some cases, LED grow lights are quickly becoming a favorite, especially given their low-cost zero-heat output.
Here we’ll be taking you through a comprehensive comparison – LED Grow Lights vs. HPS Grow Lights. With our insights, you’ll be able to select the optimal lighting for your cannabis cultivation.
LED (Light Emitting Diode)
- With almost no heat output, fitting multiple panels is easy
- Energy efficiency is fantastic requiring less power than wattage to run
- Without affecting heat, humidity stays relatively stable
- LED grow lights are compact, lightweight and easy to move
- LED lighting does not degrade
HPS (High Pressure Sodium)
- HPS lights run hot making expansion require planning
- The energy efficiency of HPS grow lights makes them a running expense
- Dedicated ventilation and humidity monitoring are needed
- HPS grow lights are typically a hefty setup more suited to long-term grows
- HPS lighting solutions need replacement every 1-2 years
Breaking It Down
Our comparison will take you through a look at how LED grow lights vs. HPS grow lights affect yield, as well as how their heat output differs, and what energy efficiency you can expect.
The potency and quantity yielded from a marijuana plant largely determine what hardware is best. HPS grow lights have been the go-to for many but LED grow lights are beginning to change this trend. Let’s see which system gives the best cannabis in the greatest volume.
LED Grow Lights
Many side-by-side comparisons of identical plants grown in identical conditions switching nothing other than the equivalent light source confirm that LED grow lights produce shorter, smaller plants. The buds grown under LED lights are typically sturdier and denser but there are far fewer bud sites. Another upside to LED grow lights is that cannabis typically flowers between one and two weeks faster, while the buds don’t suffer any degradation due to the direct transference of surface heat.
When you get your ventilation right and your intensity perfect, HPS grow lights result in taller, fatter plants with a better average yield. Cannabis grown under HPS lights have far more bud sites but flowering occurring at a slightly slower rate than those grown under LEDs.
While buds grown under HPS lighting are slightly more abundant and a bit bigger, their concentrations of cannabinoids and THC appear slightly lower due to the direct transference of surface heat and the way that this degrades the plant matter itself.
LED grow lights offer the widest range of possibilities for a grower to experiment with different arrangements and spectrums of light. Although your plants look smaller, the yield is equal to HPS grow lights and can be exceeded if you use multiple lighting panels intelligently. Without the heat, it's far easier to integrate more grow lights.
As the heat of your grow room or grow tent increases, so does your ventilation also increase in its demands. Here’s a look at which lights put out the most heat.
LED Grow Lights
You don’t get a cooler lighting solution than LED grow lights. Even when using massive panels, there is no heat. While most growers welcome the cool operation, cold climate grow ops may prefer HPS for the added bonus of heat.
With the high intensity of HPS lighting comes a large amount of heat. Your cooling will set you back a packet, while your lighting distance needs to be carefully controlled so that you don’t damage your plants. HPS has the highest potential luminosity and a broad range, but you need to monitor heat and humidity when using these grow lights.
LED grow lights are a far better option when evaluating them purely on their impact to temperature. Without the flux in environment temperature, you can rest assured that your humidity and air circulation is steady and predictable as well.
LEDs consume far less power which leads most people to believe that they are the most energy-efficient option. It is true that most gardeners will love the small amount of power that energy level LED grow lights offer, however, the number of LEDs that you need to equal HPS lighting is quite significant.
When it comes to the initial purchase price, you’ll never be able to beat the cost of LED grow lights. They’re the cheapest to setup but die-hard HPS fans won’t touch LEDs, criticizing how you need almost twice as many to reach the same output. Here’s how costs break down.
LED Grow Lights
Across the broad range of manufacturers and the countless ways that LEDs have been incorporated into growing lights and gadgetry, competition and low-cost manufacturing keep the price extremely affordable. LEDs also far outlast HPS bulbs as they never need replacement and seldom fail.
HPS and metal halide lights can cost as much as a grow tent complete with LEDs and fans. They will also need to be replaced at anything between one and two years of use as by this time the bulb would have degraded to the point where using it for cannabis cultivation is no longer viable.
When you consider the energy efficiency, purchase price, and maintenance LED grow lights are the most affordable. You may need more of them but the setup will cost you significantly less money on average.
- LED grow lights won yield, affordability, heat output, and energy efficiency, 4/4 sections compared
- HPS grow lights took no prize, 0/4 sections compared
Pros and Cons
Both high-pressure sodium lighting and LED grow lights come with their own range of pros and cons, making each a viable option to the right grower. Here’s a wrap-up of the benefits and pitfalls of each type of lighting.
LED Grow Lights
- Reduced power consumption
- Lowered long-term operation costs
- Bulbs don’t degrade in intensity
- Lower heat output
- Extremely compact designs available
- High initial setup cost
- Standardization issues across manufacturers
- Lower heat output can be problematic in cold regions
HPS Grow Lights
- High initial affordability
- Immense light intensity range
- Powerful raw light output
- Heat generated requires better ventilation
- Bulbs diminish in intensity requiring annual replacement
- Power hungry
Unless you are a veteran grower with specialized lighting requirements needing a fixed wavelength and intensity, you probably won’t need HPS grow lights. LED grow lights make for a far better option even when you expand to grow great volumes of cannabis crops.