While you might be familiar with traditional “blurple” LED grow lights, the technology has improved quite a lot over recent years. LEDs have gained traction with home gardeners as an energy- and cost-efficient option for growing cannabis, and all kinds of other edible plants, indoors.
There is no shortage of choice out there if you're interested in growing with LEDs, but there are also several important things to know and consider before you go out and purchase an LED grow light. Here we'll take you through the key points.
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What are LED grow lights?
An LED, or light-emitting diode, produces light by running an electric current through a semiconductor.
Enterprising companies have developed LED fixtures designed specifically to grow plants. These LEDs are capable of producing really bright, energy-rich light that will give your cannabis plants what they need for healthy growth throughout their life cycle.
Can you grow plants with regular LED lights?
Technically yes, but regular LEDs are by no means ideal. Plants need light, and while the LED-powered lamp you might have sitting on your desk can provide the plant with light, it's really not the type your plants need to thrive. If you use a non-specialized LED light to grow cannabis, your plants will be weak, wonky, and probably not all that healthy.
“Cannabis requires a lot of light. High-intensity horticultural LEDs that provide a full spectrum in the photosynthetically active radiation (PAR) range are required to optimize cannabis growth,” explained Jordan Stauder, Commercial Cultivation Advisor at GrowRay Technologies.
What type of LED is best for growing cannabis plants?
The original LED grow lights are often known as “blurples” because they focused on providing plants exactly what we thought they needed, since photosynthesis peaks in the red and blue wavelengths of light. Because they offered such a specific set of wavelengths, these types of lights are also called targeted or narrowband lights.
Since then, we have come to understand that plants benefit from a broader spectrum of color. While high-quality and properly balanced narrowband light can still get the job done, a full- or broad-spectrum of light will produce healthier plants overall.
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Pros of LED grow lights
The main advantages for LED grow lights include:
- Energy efficiency and the least costly in the long term
- Cooler operating temps, which means less supplemental ventilation and cooling
- Built-in cooling options like heatsinks and fans
- Fewer setup adjustments needed as plants grow
- Long lifespan due to durability
- Less maintenance needed
- A light spectrum that is tailored specifically to meet plant needs
- High level of customization available
Cons of LED grow lights
The main barriers to using LEDs include:
- The large initial investment needed
- The high degree of knowledge required
What are the best LED grow lights?
Ask five seasoned LED growers about the best LED grow lights and you'll probably get five different answers. That said, there are a few things to consider when comparing LED grow lights, and it will require digging into the product specs.
Light intensity
Consider the photosynthetic photon flux (PPF) for each product you look at. The PPF reading will tell you the total PAR light output of the lamp each second measured in micromoles. The PPF reading is a measure of how powerful the light is. In general, for a 4-by-4-foot growing area, you're looking for a PPF reading of about 1,000 to 1,500 micromoles per second (μmol/s).
Coverage area
It's all fine and good to have a high PPF value, but we need to take this one step further by thinking about how the light actually hits plants and is distributed across the canopy. Manufacturers should provide a recommended footprint for their products, which is how big a growing space they say their light will cover.
Photon efficacy
This is a measure of efficiency for the fixture. It shows how efficient the lamp is at taking wattage from your outlet and turning it into PAR light your plant can use. Obviously, the more efficient the better.
Quality of parts
Of course, you want a product that has quality parts. Perhaps of most importance is the brand of the chips or diodes used in the light. While there are many companies making good quality components for LED grow lights, some of the better-known manufacturers include Cree, Samsung, Osram, and Mean Well.
Warranty
While LED fixtures are easy to use and maintain, make sure any product you consider offers a decent warranty and comes from a reputable company.
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How to choose the right LED grow lights
There are many factors to consider when deciding on the right LED lights for you.
Your grow space
Your lighting needs will vary quite a lot depending on your unique physical space. Because of the way light is distributed by a particular fixture, it might make more sense to have a few small fixtures as compared to one large one. This is where the PAR chart comes in handy.
“LED lights come in all shapes and sizes,” explained Andrew Gaumond, a horticulturist, botanist, and Director of Content at Petal Republic. Consider this, the dimensions you're working with, and “the volume of plants you're looking to nurture as this will help to determine the type of LED lighting solution most appropriate for your growing space.”
So for example, if you're lighting a 4-by-8-foot space, perhaps you'd get better overall coverage with two lights that have a single point of light emission versus one light that has multiple, spread-out diodes. You can compare the PAR charts of different lights — while also weighing optimal light coverage against your budget — to make the best choice.
The product specs
Do your homework. Comparing one product's advertised wattage and price to another product's wattage and price is like comparing apples to oranges. Look at metrics like PPF, the PAR chart, and photon efficacy to truly compare products.
Your budget
LED grow lamps can be quite expensive, though there is a wide range of products out there at various price points. That said, you generally get what you pay for with LEDs, so if a product is touting superior specs at a low price, be suspicious. Considering that LED fixtures should provide years of useful life, it might be worth the investment to spend a little extra. But if budget and initial investment are driving considerations for you, more traditional lighting options like compact fluorescent lights (CFL) or high-intensity discharge lights (HID) might be the better way to go.
Bottom line
LED grow lights are becoming increasingly popular with home gardeners and commercial cannabis growers alike. With both the technology and price points becoming more and more attractive every day, LED lights might be a great choice for your next grow. Because quality and overall value can vary greatly, be sure to do your homework before purchasing by closely examining product specs, reading user reviews, and talking to other growers.
