Are you already grow plants in a marijuana grow tent? Do you need a grow light? There are various options for indoor garden lighting, but no others offer the energy efficiency and overall benefits to plant growth that LED grow lights can offer. LED lighting wasn’t a viable option for indoor gardening until after 2014, when scientists finally developed a blue-spectrum LED. Until then indoor growers traditionally relied on two types of HID bulbs, High-Pressure Sodium (HPS) and Metal Halide (MH), which offered the necessary light for flowering and vegetative growth, respectively.
Blue-spectrum LEDs were a game changing breakthrough.
All growers know that full spectrum LED grow lights have quickly become an industry standard for both the hydroponic hobbyist and the seasoned commercial growers.
Marijuana plants, regardless of where you are growing them – indoors or outdoors, need lighting. Light is very important for plants to grow as it helps them with the process of photosynthesis and helps them produce chlorophyll as well. Photosynthesis is an important process because that’s how plants prepare ‘food’ which gives them energy. Sunlight also helps break down various sugars and compounds in the plant’s body and it is also based on the lighting hours that they ge that the marijuana plant’s levels of CBD and THC are also affected at times.
Photoperiod is also very important for regular plants (non-autoflowering plants). These plants grow based on the sunlight that they get and they need about 22 to 12 hours of lighting based on the phase of growth that they are in. Different phases of the growth cycle not only need different amounts of lighting but also require different types of light. When the plant is in its early and vegetative stage of growth, it needs more of ‘blue light’ which is on the cooler spectrum of lighting. When the plant matures into pre-flowering and flowering stages, it requires red lighting. However, most growers prefer providing a combination of both these kinds of lights for a better result.
Your grow light draws electricity to operate the ballast and bulb. Grow lights can vary in wattage, from as little as 50-watt NIR bulbs to 2,000-watt HPS or LED setups. Some growers use multiple lights in series, boosting the power capacity of their setup to meet the harvest needs.
Some lights have higher wattages than others. For example, LED lights have lower wattages than HPS or metal halide bulbs. Therefore, these light sources consume more power than LEDs, cutting down on the costs of operating your indoor garden.
Each growing light has a specific design to cover a growing area. Trying to grow outside of this light footprint will produce lackluster results. The wattage of the bulb, and it’s operating height are the two most significant factors to consider when deciding on the right light footprint for your garden.
For example, a 1,000-watt globe operates at three to six feet above the canopy, and it’s suitable for a growing footprint of up to 3-square feet. When setting up your grow light, we recommend you follow the manufacturer’s guidelines for distance from the bulb to the canopy.
You can tweak these settings with small tests during your first harvest. It might take you the entire growing season to find the right setup for your garden. Finding the proper placement to provide optimal heat, intensity, and footprint takes some time and testing.
The photoperiod of your light refers to how much light you give your plants over 24-hours. If you’re growing outdoors, you have a limitation on the photoperiod, thanks to the sun. In the height of summer, you can get up to 12-hours of light each day, while the wintertime may shorten daylight to 6-hours.
When growing plants indoors, you can change the photoperiod to whatever length you desire. You can run a 24-hour photoperiod with consistent lighting if you want.
Some plants experience a change when they start to experience a shortening in the photoperiod window. This shortening of the photoperiod mimics the days of the harvest season, and the plants begin to flower.
How to Use Grow Lights for Indoor Plants?
How far should LED Grow Lights be from the plants?
For germination, the light should be about 30 inches above the plants. For vegetation phase, lower the light to about 24 inches above the plant top. For flowering phase, lower the light even further to about 18 inches. As you lower the light, the light’s footprint grows smaller. This means that plants on the outside of the footprint might not be getting optimal light energy and you may need to add an additional light.
How Long Should I Leave LED Grow Lights On?
With the low operating temperatures of modern LED lamps, there is little concern of heat or fire (which is not the case with HID bulbs). The question, then, is how long do your plants want the lights on for?
You can find a more thorough explanation up above, but generally speaking you want around 16-18 hours for vegetative growth and around 10-12 hours for flowering. This simulates the shortening of natural daylight as we transition from summer into autumn.
Does more light equal more yield?
You may not realize it, but by asking that question you have touched on one of the biggest discussions in the indoor grow lighting industry, as well as the indoor gardening community.
When you get into how it all works, light is some amazing stuff. It doesn’t really act like anything else in the world, so it can be difficult to visualize how it works without having something else to use as a comparison or reference. For example, we may imagine light pouring like a liquid or like smoke, until it fills a space up – that’s close, but not quite right. We could describe it as being like radiation, emanating out and being absorbed by anything in its path…a little closer, even, but still not exactly the same thing.
Light has unique properties – in order to determine whether it is as simple as (more light = more growth) or whether dumping all those photons is wasteful or even harmful, we need to better understand how it works in the first place.
How many watts per square foot for LED Grow Lights?
Generally, 30-50 watts per square foot is sufficient. Some growers recommend a higher level of 65 watts per square foot. Higher than 65 watts risks burning your plants. Remember that with LED Grow Lights, the wattage specification should be the manufacturer’s estimate of the actual watt output of the LED lights, not the power draw at the wall and not the wattage the manufacturer states for an equivalent HID light.
Are LED Grow Lights bad for your eyes?
Yes, you can get eye damage from LED Grow Lights and any bright light, particularly in a closed space like a grow tent with reflective interior. Just like looking at the sun. You should always wear good-quality protective sunglasses with good coverage of your field of vision.
Whether you’re new to growing indoors altogether or just new to growing cannabis plants with LED plant lights, you may not be familiar with some of the unique characteristics of LED lighting. Here are the main factors you want to check on when purchasing LED horticultural lights for your cannabis grow.
The factors are listed in no particular order. Only you can know which one is most important to you, given your specific growing situation.
You may have noticed that most LED lights have two different wattage figures. One of these is the potential wattage and the other the actual wattage. The potential wattage is the wattage the light could run at if the LED chips were running at full power. For example, a light with two hundred 3w LEDs has a potential wattage of 600.
LED chips are never run at full power, though. Doing so would considerably shorten their life span. Generally, they are run at 50 to 60% of their potential power. This is their real wattage and is the amount of electricity the light will actually consume.
The 600 watt LED grow light from the example above would probably have a power draw of 300 to 400 watts. And lights listed as 300w don’t actually have a power draw anywhere near that much either, especially if it’s a Chinese brand (they tend to exaggerate a lot).
Most indoor horticultural LED lights use LEDs in multiple colors. The majority will be various shades of red and blue, with the better lights also using some white LEDs as well as some infrared and ultra-violet ones.
This mix of colors gives you all the light plants, including cannabis, need for every stage of growth: cloning, veg and bloom. It is referred to as full-spectrum light and is generally what you want. All of the fixtures above, from BestVA to Phlizon, offer some variety of this light spectrum.
There are a few exceptions. If you are looking for a light to only grow clones or to just veg plants, then you might want to check out one with mostly blue LEDs. If you are looking for a light to supplement your existing setup to give your plants a boost during the flowering stage, you’ll want one with mostly red LEDs.
Finally, I need to mention all-white LED fixtures. These lights use only white LED, which gives them a spectrum similar to natural sunlight (which is also a mix of the HPS and metal halide spectra). Proponents of white light claim it is best for plants, because it gives them the light they are used to from the sun.
More and more, the indoor cannabis industry as a whole is moving toward white light. White LED grow light fixtures are becoming much more common on the market as a result.
And white light does work well to grow and flower plants. But it includes a lot of light in the yellow and green ranges, which is light plants do not use much during photosynthesis. Thus, it goes to waste, right?
That has been the case made by manufacturers (and fans) of fixtures with mostly red and blue LED lights. They say these are more efficient, because you are not using any of the electricity you paid for to produce light that plants don’t want.
But plants do want that light. Sure, they don’t want as much of it as they do of light in the red and blue wavelengths, but they do still want it. That is why the best-selling LED grow lights these days all include white LEDs on their lights. And many use mostly white LED light.
For LED lights, the most widely used measure of intensity is PAR (technically, it is PPFD and not PAR, but most still refer to it as PAR). It stands for Photosynthetically Active Radiation and is used to measure the amount of light in the wavelengths that plants use for photosynthesis. Some brands will list the lumen output, but that isn’t all that useful for grow lights.
Some brands give PAR readings for their indoor plant lights; others do not. Those that do often only give one value, which doesn’t really tell you much about its effectiveness for vegetative growing, much less blooming.
That value was taken dead center beneath the light. A large value here means you have a powerful light in the middle of the coverage area, but it tells you nothing about the strength of the light around the edges.
Ideally, manufacturers will provide a PAR footprint that shows PAR readings throughout the coverage area. Most do not do this, however, so you will often have to look to tests done by third parties, such as review sites, for this information. For white LED lights, lumen output can have some value. For others, it is mostly useless.
This refers to the area a grow light can cover while still providing enough light for the plants in that space. For the flowering stage of growth, plants need more light, so you will have to move the light fixtures closer to the canopy. This increases the intensity, but also decreases the coverage area.
This is why LED lights have a smaller coverage area for the flowering stage than they do for vegging. Always make sure the space given by the manufacturer is for blooming, unless you only plan to veg with your light.
Te best LED grow lights give off far less heat than HID bulbs, but powerful LED diodes still emit enough heat that they require cooling. Any larger LED fixture must have heat sinks to reduce the amount of heat emitted and internal fans to disperse whatever heat remains.
You want to make sure that a LED light’s cooling fans and heat sinks are adequate for the amount and strength of diodes in contains. If it isn’t, this will considerably shorten the life span of the LED chips and make them far less efficient.
Another issue to consider is noise. Fans can generate a lot of noise, so fixtures with multiple fans will be much louder than you might think.
When you add their noise to that of oscillating fans and exhaust vans for your tent, you can end up with a fairly high noise level. If this is a concern, consider a fixture with fewer, or even no, fans.
Final thoughts
If you’re thinking about starting an indoor garden this year, you need to get the best advice possible. We recommend signing up for a forum.
You’ll find plenty of experienced growers willing to give you some advice. Get recommendations on the best equipment brands and avoid making the same mistake novice gardeners make in their first season.
There are dozens of grow lights out there to choose from. However, only a select few provide the best light for your garden. Make sure you select a device that suits your gardening needs and your budget. By the way, I want to introduce you a new brand ECO Farm LED grow light, they are with high quality and nice service.
Quality LED grow lights are the best solution we have today for growing plants indoors. They are more efficient that traditional forms of light, meaning they produce more output, while using less electricity and producing less heat.