If you are planning on growing your Cannabis indoors, you most likely have already taken a look at the different lighting options available.
Every grower has his or her personal preference for the best indoor marijuana grow lights, and you have probably already received advice about setting up your own lighting system in one way or another.
But how do you know which grow light will suit you the best for growing marijuana indoors?
Under natural circumstances, the cannabis plant sprouts in the Spring grows over the Summer, then flowers when days become shorter and less light is available. The plant’s lifecycle is driven by the photosynthesis (wiki) process. It is sometimes referred to as the cannabis light cycle.
When growing indoors, you can simulate this process. With grow lights, you can maintain a light schedule that tricks your plants into thinking they should start flowering. Not only that you also control light intensity, the light spectrum, and other factors that help your plants grow.
What defines the best grow lights?
When talking about cannabis grow lights, two main factors are important:
- Power consumption: Is your electricity network up to it, and can you pay the bill?
- Cannabis yield potential: More light equals a bigger harvest.
So, the ideal grow light is efficient on electricity while generating a heavy yield.
Other factors that come into play are:
- Light intensity: The lumens you expose your plants to.
- Light distance: Too close to the canopy burns the leaves, but too far isn’t efficient.
- Light schedule: How many hours of light are your plants getting during each stage?
- Light spectrum: The color of the light required for different grow stages.
- How many plants you have: Will your grow room be overcrowded?
- Climate control: Those lamps can get hot.
- Your budget: Some setups can be expensive.
With that in mind we’re going to look at what types of grow lights are available on the market.
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What types of grow lights are there?
There are a variety of grow lights in the market, such as incandescent lights, fluorescent lights, high-intensity discharge lamps (HID), and light-emitting diodes (LED).
If you’re growing indoors, you’ll have to decide how best to set up your own lights. There are a lot of different options when it comes to the lighting system, and there are a lot of opinions, too.
When it comes to lighting, you have a lot of different choices. We covered some of the basics in types of lighting in the last section. In this section, we’ll cover more about the different choices you’ve been presented with, and discuss some of the pros and cons of the different lighting setups.
Many growers argue about which lights are the best, but, in general, every type of light specializes in a certain phase of growth or a certain type of job. It’s up to the grower to decide how much time and money they want to invest into their lighting systems.
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CFL – Fluorescent lights
In the early days of Cannabis cultivation, fluorescent grow lights were used by growers to simulate the sun, just as they had been used for many years by farmers and botanists for indoor growing and early germination in cold climates.
Unfortunately, fluorescent lights are expensive and you require a lot of fluorescents to simulate natural sunlight.
Not only that, but it requires a lot of different types of fluorescent lights to mimic the full spectrum of natural light.
Check the best CFL lights at this link
Nowadays, growers still use fluorescent lights when plants are extremely sensitive to heat.
This applies to cuttings and seedlings in the early stages of growth.
Keep in mind, however, that the fluorescent lights still need to be close to the plants themselves, usually about 5 cm away.
Fluorescent technology has changed somewhat, too, and now fluorescent lights offer slightly higher quality growing for Cannabis than they used to.
If you’re using fluorescents, you’ll also want reflectors to go with them, to maximize their efficiency and save yourself some energy.
HID – High-intensity discharge lights
High-intensity discharge grow lights were first invented for a huge scale, for use in public arenas and stadiums.
These sorts of light are very powerful, and they’re used by a lot of botanists and horticulturists to grow lots of things besides Cannabis.
But they do work quite well for Cannabis, so let’s talk about them.
Within the various types of HID light, we have:
- Metal halide lights (MH)
- High-pressure sodium vapor light (HPS)
We’ll cross mercury lights off the list right away because their lumen-to-watt capacity is too low for them to compete with the others.
MH – Metal halide lights
Metal halide grow lights produce light by arcing an electric current through mercury gas mixed with some sort of metal iodide such as thallium, thorium, or sodium.
The light that it produces falls into a perfect range of the color spectrum for the growing phase of Cannabis.
In particular, it’s good for producing foliage.
Plus, it’s flexible: 1000-watt metal halide lights can be used to induce the flowering period in plants.
Growers in the United States used metal halide lights for a long time after the introduction of HID lighting, and they performed well for all phases of plant growth.
HPS – High-pressure sodium vapor lights
In the mid-80s, when communication began in earnest about growing practices and how they differed in the US and Europe, growers, and cultivators discovered a couple of unusual differences.
First of all, Americans were using a lot more power than their European counterparts.
One of the reasons for this is that most Europeans were using horizontal reflectors and HPS grow lights, whereas Americans were using vertical reflectors and metal halide lights.
HPS lights have the ideal color range for Cannabis plants during their flowering phase while metal halides are superior for the growth phase.
They function similarly to other HID lights and create light by arcing electric current through a bulb containing xenon and sodium gas.
They emit a dull pink glow that quickly turns into an orange-pink light once it warms up.
HPS lights work spectacularly for indoor cultivation, especially for a plant going through the flowering phase of growth.
You can purchase HPS lights in a number of different strengths: 250w, 400w, 600w, and 1000w.
Don’t even think about using the 1000w light unless you’re growing a whole field in an underground bunker.
In order to take advantage of the strength, you have to cool your grow room with an air conditioner.
Your best bet is to purchase two 400w or 600w HPS lights: these will evenly diffuse light for your plants, and they aren’t overly lot so you have a low risk of heat damage.
Keep in mind that you might want to use a fluorescent light in conjunction with your sodium vapor light.
‘Agro’ type lights are also a good choice. Made by Philips, the ‘Agro’ light slips into the blue spectrum, and the lights are easy on the pocketbook.
You can expect to replace lights about once every year if you have them running a lot.
LED – Light-emitting diodes
Can you use any LED light as a grow light for my plants? No, not any old LED light is suitable for growing weed. To ensure that your plants are receiving the optimal light, you have to make sure that it is coming from a full spectrum LED, which comes from the best LED grow lights.
LEDs (light-emitting diodes) have become ubiquitous in the lighting world over the last decade.
While not necessarily the ideal light for growing cannabis, LED lights offer several advantages.
First of all, they are low voltage, which means less money is spent on upkeep and electricity to keep them running.
Coupled with this, they produce very little heat, which means you don’t need to worry about overheating your grow room if you use LED lights.
It also further reduces your reliance on ventilation and fans, adding even deeper energy savings.
In fact, depending on your operation, you may very well need to heat the room if you are using LED lighting.
For growers prioritizing privacy, LED lights offer an additional bonus— the low heat makes LED lighting virtually impossible to detect with thermal imaging techniques commonly used to spot the infrared heat of more conventional HPS lights.
LED lighting is also quieter than the other lighting options, without the background hum emitted by HPS lights.
Remember that not all LED lights are created equal! Be sure to check your bulbs and make sure that they are high-wattage and have a high lumen value.
The higher these are, the brighter your light will be.
You also want to make sure that the LED lights you choose have been specifically manufactured to emit light at the full spectrum of color your plants need for proper photosynthesis.
LED lights do have a higher initial investment than some of the cheaper options, which can cause some growers to be skeptical about using them.
Then again, they are very efficient. LED lights waste far less energy as heat, assuming the room doesn’t need to be heated, and those savings on electricity will pay for themselves in just a couple of years.
You also don’t need to worry about setting your grow room on fire, and LED lights last for a long time.
Some manufacturers advertise more than 100,000 hours of life in their LED bulbs, which gives you enough time for almost ten years of harvesting.
What grow lights do you need
Lighting systems will vary in intensity, spectrum color, and the underlying technology.
It will come down to the size of your grow room, your electrical needs, and how much time and money you’re willing to invest into lighting up your grow room.
When you choose a light system, first plan on how much light you need to use, then compare that to how much light you can realistically provide for the plants.
If you live in an old house with a direct current, it probably won’t be much!
Be realistic, and remember that lights use up a lot of power.
The real key to deciding what sort of light you need is to figure out the size of your grow area.
If you’re using an area that is smaller than 5 square feet, consider using a fluorescent or HPS 250w light.
Fluorescent lights are small, and they will help your cuttings root well. Later, as plants get large, you’ll want an HPS light.
Ideally, if you’ve got the space, you should use a metal halide light when your plant is in its growth phase and an HPS light for the flowering phase.
If you use a metal halide light for both growth and flowering, you’ll be ok, but your plant will have more foliage than necessary and not as many flowers.
This means you’ll have a lower yield.
If you use an HPS light during the growth and flowering periods, you’ll end up with a plant that is long but maybe not as structurally sound as you’d like.
If you only have space or time to use a single light, consider using one of the ‘Agro’ types of light.
Above all, be smart about using what you’ve got. It’s important to have lighting, but you need to plan it out, too.
You can’t just fill a room with ultra-high-wattage lights and expect your plants to thrive.
Don’t waste valuable power, and learn how to make use of your resources.
Thanks for reading. Please leave comments or questions below and don’t forget to download my free Grow Bible!