LED vs HPS Grow Lights: Pros, Cons, and Details You Need To Know
If you’re looking to grow plants indoors and/or under grow lamps, one of the most important decisions you’re going to have to make is the type of bulb to use. Two of the most common and effective growing bulbs are LED and HPS lights. When it comes to LED vs HPS grow lights, everyone has a different opinion. These two lights are often considered the giants of the industry, and they each have their advantages and drawbacks.
We’re going to cover growing with LED vs HPS grow lights in this article, and we’ll provide information that beginner horticulturalists need to make an informed decision. There’s no one-size-fits-all correct answer, and when deciding between LED and HPS bulbs, you’ll need to consider your needs, budget, and other factors.
What is an LED Grow Light?
The LED took many years to develop for several reasons - the first discoveries were well ahead of their time, other discoveries were lost due to war. -LED History: Story of the Light-emitting Diode
You’ve probably seen the term “LED” tossed around before as “Light Emitting Diodes” are used in various technologies, including TVs, and yes, grow lamps. We’re going to skip the science details, but it suffices to say that electricity is run through a diode (a type of semiconductor) to emit photons of light.
Plants, as most horticulturalists know, need light to grow. While most plants rely on the sun for light, you can use artificial light to grow plants as well. You can use various light bulbs, including some used in consumer lamps and the like, to grow plants. That said, growth rates may vary from bulb to bulb (and plant to plant).
LED lights generally emit “white light,” which is full-spectrum light, meaning every common color wavelength of light is present. That said, you can purchase LED lights that produce yellow, red, and other colors. Different colors of light do different things. Red lights, for example, encourage the growth of stems.
When it comes to deciding which type of lights to grow with, it’s important to consider the strengths and weaknesses of both. Let's begin with LED grow lamps.
LED Grow Light Strengths and Weaknesses
LED grow lights have become increasingly popular in recent years. LED lights have grown cheaper, and when it comes to energy use, they’re among the best lighting technologies currently on the market. Outside of growing lamps, LED lights are among the most popular consumer bulbs.
Electricity prices in many countries and areas have trended up over the years. These bulbs are also much more efficient than many other types, including incandescent and HPS bulbs. Even as energy prices are going up, some have found their energy bills dropping due to LED lights and other energy-saving tools.
LED lights also don’t generate a lot of heat. Depending on your needs, this can be either positive or negative. If you’re heating your growing spaces, especially during cold seasons, you may miss the heat provided by other bulbs (including HPS). Then again, if heat is a nuisance in your facility, LED bulbs may offer relief.
Besides less electricity use, LED bulbs typically feature a long life span, lasting for 50,000 hours or more. Not only can you hold off on buying expensive bulbs, but you also don’t have to expend as much labor power replacing them.
These bulbs also provide a full spectrum of light, which may benefit plants throughout their growth cycle. Further, these bulbs are also quite compact and can be set up even in tight spaces.
In total, LED lights are affordable, especially when electricity costs are factored in, and also flexible, fitting into a range of facilities and working well as grow lamps for a wide variety of plants.
High-Pressure Sodium Light Bulbs
Early inventors of the sodium lamp knew that better efficiency could be achieved with higher pressure in the arc tube. -Sodium Lamp
If you’re unfamiliar with the term, the full name for HPS bulbs, High-Pressure Sodium, can be both enlightening and confusing. HPS bulbs contain highly pressurized vapor that contains sodium metal and other gases, such as xenon and mercury. An electric arc is sent through the gases, and the resulting interaction produces light.
Researchers have been working on sodium vapor lights since at least the 1920s, although high-pressure variants were not successfully tested until 1959. HPS lights are often used as streetlights and in industrial operations. However, some growers also like to use these bulbs for various reasons.
Many horticulturalists report that flowering plants especially do well with HPS grow lamps. However, the results so far aren’t conclusive, and your crop yield experience may vary. Let's review the benefits and concerns with this type of lamp.
HPS Grow Light Strengths and Weaknesses
Some growers prefer HPS grow lamps to LED lamps due to various reasons. HPS bulbs offer some benefits but also some drawbacks. Let’s take a look.
HPS bulbs are often much cheaper to purchase compared to an LED light. In fact, Consumers can sometimes purchase HPS bulbs for less than half of the cost of a comparable LED bulb.
These lights use mercury, a hazardous substance. These bulbs may pose a slight risk, especially if damaged or misused. Further, disposing of HPS bulbs can be difficult owing to the mercury. You may need to take them to specialized disposal facilities.
Generally speaking, HPS bulbs don’t last as long as LED bulbs. Often, they reach the end of life at about 20,000 to 24,000 hours. HPS bulbs gradually lose output over time, and even if your bulb is still producing light, you may find yields slowly decreasing.
On top of that, HPS bulbs are not as energy efficient as LED lights. Compared to many other bulbs, HPS lamps are quite energy-efficient.
HPS bulbs also produce quite a bit of heat. If you’re growing crops in the winter or otherwise need to heat your facility, this could be a good thing. Otherwise, you may have to set up cooling systems.
Some HPS bulbs produce a lot of red light, which seems good for many plants, including flowering plants. Some tests have found that HPS bulbs produce higher yields, although the data so far isn’t conclusive, and more research is needed.
Conclusion: LED VS HPS Grow Lights and Choosing the One That’s Right For You
There’s no “right” answer as far growing with led vs. hps grow lamps, and ultimately, you’ll have to decide which is better for your specific needs. If you'd benefit from bulbs that generate heat, HPS lights might be a better choice. That said, in terms of flexibility and energy efficiency, LED lights are hard to beat as grow lamps and light bulbs in general.
Price is one of the major considerations, but there’s no easy answer here either. LED bulbs cost more upfront but are much cheaper to run. HPS bulbs are cheaper per unit, but they also typically don’t last as long and consume more electricity.
Given the lower upfront costs, beginner horticulturalists may want to learn the ropes with HPS grow lamps. Large operations, meanwhile, may get the most out of LED bulbs.
When deciding between LED and HPS bulbs, a horticulturist needs to consider local climate conditions, energy prices, the specific plants they’re growing, and other factors as well. Make sure you don’t rush your decision and find the growth lamps that are best for you.