How To Choose the Best LED Grow Light For Indoor Growing Plants
Look up the brand; website, socials, responsiveness
If you're going to spend a significant amount of money on a grow light, you want to be sure you're buying it from a good and reliable source. When you find an interesting light on Amazon, for instance, look up the brand elsewhere. Do they have a website? Do they have social media channels? Can you reach them on Facebook or by email? A complaint we often see in the business is that some brands don't reply to customer questions or emails. To us, this is ridiculous as we feel that a fairly expensive product should also come with good after purchase care.
One more thing. A high review count on Amazon doesn’t always equal a good product. As several news sites report (eg. CNN), there are plenty of fake or bought reviews floating around on Amazon. Apply critical thinking!
What Color Light is Best for Plant Growth?
Violet-blue light in the 400 – 520 nanometer range encourages chlorophyll absorption, photosynthesis, and growth.
Red light in the 610 – 720 spectrum range promotes flowering and budding.
Grow lights should provide the proper spectrum of light for photosynthesis, which key to plant growth. Before purchasing a light, be sure to check out the provided color spectrum. Lights that can provide a full spectrum are the ideal choice for your growing space.
This is where LED lights come in handy. Most LED growing lights offer both types of color spectrum lighting, so you can get all the benefits.
Red and blue light are crucial
If you would like to grow from seedling to flower, then a full-cycle LED grow light is recommended. A full-cycle grow light will provide your plants with the blue and red wavelengths that are needed for optimal growth. Blue light mimics the long day, summer sun and encourages vegetative leaf growth (MH, or Metal Halide, lamps also provide this function). When choosing an LED grow light ensure the unit includes blue lights in the range of 440-470nm. Red light is also important in plant growth and is a primary driver for photosynthesis. Red light takes the place of the short day, autumn sun. (HPS, or High Pressure Sodium, lamps provide a red-leaning spectrum). When combined with blue light, a hormone cascade is created and the red wavelengths begin to encourage flowering. Look for lights that have red light in the 640-660 range.
Many LED grow lights are full-spectrum grow lights and contain blue, green, red (which creates a white light or reddish light depending on the amount of green) and somtimes infrared (IR) and ultraviolet (UV). Greenlight, IR, and UV have been shown to increase plant growth (green light and IR) and flower quality (UV).
ECO Farm ECOZ 1000W Samsung 301H Chips LED Grow Light With Separately UV+IR Control
- Chanels Dimmers, VEG switch , Bloom switch ,UV switch separatly controlled, Freely adjust the lamps according to different growing stages;VEG dimmer to control white light 5000K, one Bloom dimmer to control white light +red light ( 3000K+660nm+730nm), and UV dimmer to control UV 395nm.
UV is a supercharger
In addition to red and blue diodes, you may consider a light that contains UV wavelengths. UV light activates the plant's defense mechanisms, affects plant development, growth, and metabolism. UV wavelengths can also increase THC. Choose LED grow lights that have diodes in the 315-400nm range (380nm is common.) UVA is a common LED wavelength used in grow lights. UVB is more expensive and is not seen too often in LED grow lights.
ECO Farm 30W LG UV395nm Supplemental Lighting Quantum Board
Grow area (light footprint)
Ask yourself, how many plants do you intend to grow? How big are they expected to grow? How large area does your light need to cover?
As light (and water and nutrients) is your plants' "food", if they receive less than required, the plants will not grow to their full potential, as per the picture above.
Not every square inch (or square centimeter, for non-US growers) of the plant needs maximum possible light coverage for the plant to thrive, but the majority (the more the better) of the plant should be well illuminated.
If you're growing cannabis, Indica strains grow smaller than sativas in general but it also comes down to how you manage the plant throughout its grow cycles. You can train the plant to grow a certain way and have a certain size.
Beginners that are still learning plant management will likely have smaller cannabis plants, around 2 square foot (0.2 square meters) per plant, than experienced growers.
Find a grow light or a number of grow lights that cover the area of your grow. Sometimes it makes more sense to buy two (cheap) lights rather than one expensive.
The area a light illuminates should be specified by the grow light manufacturer. If this info is not available, it suggests the seller is either withholding information or doesn’t really know how to best use the light.
Light output and intensity (PPFD)
Your plants need a certain amount of light to grow. To keep this guide short and in point, your weed plants will need around 300 PPFD (sometimes also incorrectly referred to as PAR) when they are small and in their vegetative stage, then about the double (600 PPFD) during flowering. Light will still be utilized beyond this level of intensity, but less and less efficiently. Experienced growers are often aiming for upwards 900 PPFD and with added CO2 and the right ratio of nutrients, temperature, and humidity, cannabis plants can take even a bit higher PPFD levels but 600-900 is still a good general rule of thumb.
Smaller plants like herbs (basil, rosemary, and microgreens) require about 150-200 PPFD for good results while veggies (cucumbers, peppers, tomatoes) need a bit more, 200-600 PPFD.
Don’t be Cheap
LED grow lights don’t come cheap. Regular LED bulbs for home lighting use are not as cheap as incandescent or fluorescent bulbs, so for LED grow lights that provide a life for plants, you can expect that these would cost a lot.
While you may find cheaper variants of LED grow lights, consider if it’s really worth it. Sometimes, cheap doesn’t always save money because of poor quality, which may even make you spend more on repairs or replacements. So, always choose the one that gives the best value.
The best LED spectrums for plant growth
In summary, the best lights for growing indoor plants will include red and blue LEDs (at the correct wavelengths) or a full-spectrum white light. UV diodes may be included to enhance a plant's physiological functions, but these are not required. A 6:1 or 5:1 ratio of red to blue is ideal for boosting yields, but can create stretched plants during Veg and reduce flower quality. A red to blue ratio or 2:1 or 1:1 is ideal for keeping stout and increasing resin production. Of course individual results will vary based on grower experience, strain, nutrients, environment, etc. Before you purchase and LED grow light, look at the spectral curve to ensure it is what you and your plants desire.
Understanding LED Light Output
We've seen a concerning trend in LED grow lighting which revolves around the promotion of false and misleading lamp wattage. This is important to indoor growers because the amount of photosynthetic light output a lamp produces is limited by the amount of wattage the unit draws from the wall. Lower light output levels will affect crop yield, potency and flavor profiles.
Advertisement with Misleading Claims
It's actual wattage is 330 watts. However it advertised as a 1200 watt grow light. That is a 300% inflation of actual light production output which is very misleading.
LED diodes output visible light energy in lumens or luminous flux. Each diode is supplied incoming voltage which is distributed to the diodes as a portion of the total amount of wattage the unit draws from the wall. Each LED light is limited to a specific maximum wall draw based on the voltage supplied to the Driver / Power Supply Unit. It varies slightly if the light is wired to accept 110/220/277 volts. But the variance is small as compared to the lamps wattage wall power draw.
Many of the products with inflated wattage claims also lack information on photosynthetic light output. The total amount of photosynthetic light being created is measured in a lab using a machine called an Integrating Sphere. The sphere measures total luminous flux output which can be translated to Photosynthetic Photon Flux or PPF. Nearly every manufacture or lighting worldwide owns an Integrating Sphere, and in order to secure UL or ETL safety ratings these products are also sent to third party labs who use a sphere to test the total light output versus energy consumed. We suggest that consumers buying LED lighting for indoor growing ask the supplier how much PPF the light is producing. This is important information needed to do side-by-side comparisons between grow lights. There are a lot of variables to consider when buying a grow light but at a minimum, the total amount of watts being consumed by the light (power draw at the wall) and the total amount of photosynthetic light (PPF) being created is important.
