Growers Guide to Grow Lighting for Cannabis

With thousands of lighting companies out there a thousand of types of lights, we understand that customers can have a hard time finding their ideal grow lighting for Cannabis. If you would like to grow cannabis indoors you will need some type of grow light, to light your plants from.

In this article we will break down the types of lighting, when you should use these types of lighting. We will also give you some recommendations from lights that we have used over the years and really liked.

If you have already started to think about growing cannabis indoors then most likely you have already been looking at the grow lighting currently on the market. If you come back next month most likely there will be something new on the market for the “best grow lighting”.

The market has changed so much just in the last couple of years, it can be hard to figure out what is the most awesome light. You want a light that will still be great in the future.

One thing that you will learn early on in the cannabis growers’ space is that everyone has a grow light that they love, and one they didn’t love so much.

Although many growers will disagree with us, we will give you the best lighting guide we can to help you grow the best cannabis you can.

Grow Lighting for Cannabis

What is the Purpose of Grow Lighting for Cannabis?

Cannabis is a high light loving plant. This means that it enjoys a strong lighting source to grow, strong and healthy. For this reason, you can just take a home fluorescent light and expect to get amazing yields right off the bat. Home fluorescent lights are much to small and not powerful enough to light your plants for flowering. To put this in perspective you will need about 100 of these to flower a cannabis plant efficiently.

Cannabis plants use the light from your grow lights the same way that they use the sunlight to grow. The light helps the plant’s photosynthesis. This process takes place inside you plant leaves and give the plant the energy that it needs to grow larger.

The Importance of Plant Lighting Spectrum

All cannabis plants have what is called photoreceptors, what these do is trigger different growth types when activated by photons of specific light color wavelengths. This is important because you can use different lighting spectrum (colours of light) to affect and change the way your cannabis plants grow.

Growers should also remember that while changing the marijuana plants lighting spectrum, it is also working in a larger process that also needs to be controlled as well. Some of these factors for cannabis are light intensity, photoperiod, growth environment, cannabis strain, and plant genetics.

Grow Lighting for Cannabis

Most important Cannabis Grow Light Spectrums

These lighting spectrums are most important to cannabis growth.  

Grow Lighting for Cannabis Spectrum

Blue Light Wavelengths Spectrum (400 – 500 nm)

Blue light is normally used for vegetative growth for cannabis plants. Cannabis plant only use a small amount of blue light when growing. The blue lighting spectrum promote plant compactness, stimulate root development and also helps the plant produce secondary metabolites.

Blue light waves also help increase chlorophyll accumulation (keeps the plant green), and will encourage the plants stomatal opening to exchange gases in the cannabis plant. This will create a healthier plant overall. Another cool thing about blue light wavelengths is that it can improve terpene retention in various strains of cannabis.

Red Light Wavelengths (600 – 700 nm)

The red-light wavelengths are by far the most important for stimulating photosynthesis and promoting cannabis plant biomass growth. When using red light to grow plant is it recommend to add in blue lighting to help with plant stretching, as this wavelength will create tall lanky plants.

Green Light Wavelengths (500 – 600 nm)

For many years growers wrote off green light wavelengths as they were no absorb by plants chlorophyll. This has changed recently as be studies that suggest that green wavelengths are important to cannabis photosynthesis, this is especially true in lower leaves. When the plant can no long take in any important red and blue waves, green light waves can still excite electrons within chlorophyll molecules deep in the cannabis leaves, this works very well for lower leaves of the plant.

It is believed that for this reason green light can enhance photosynthetic efficiency, and may even increase bud yields.

Creating a good Mix of Lighting Wavelengths

For the best and healthiest cannabis plant environment it is always recommend to use a good mix of lighting wavelengths in your cannabis growing spaces. When shopping for a grow light you are able to check the lighting graph that is normally provided with the lighting specs. This is an example of this where you can see how much of each wavelengths the light will output.

Things to Remember when Buying a Cannabis Grow Light

When shopping for a grow light you will want to remember these things that will help you pick the right one for your grow.

Cost of the light versus the cost of operating the light long term

If you are on a tight budget buying the right grow light is a big decision and cost to put out upfront. While some lights cost less to run, will they provide you will enough cannabis buds for your usage? Some lights like LED’s will cost your far more to buy in upfront costs, but will cost much less in energy costs over the long-term making up for the upfront costs.

Can your ventilation deal with the extra Heat in Summer months?

HID Lighting can generate a ton of excessive heat in your growing space. It is up to the grower to keep temperatures in the correct range for the best growing conditions in your grow room. Picking a light that generates lots of heat will require far more ventilation to keep the room in the correct temperature range.

Grow Lighting for Cannabis Hot Tip Burn

How Much room space does your grow light have to cover?

All grow light come with a set amount of space they can cover over the plants with optimal growing conditions. For growers it is very important to buy a grow light that will cover the amount of space you will be growing in. If your grow light is only rated for a 3X3 growing space and you place the light in a 5X5 growing space, the plant on the edges of the space will suffer from lack off a good lighting source.

On the flip side of the coin buying a grow light that is way to powerful for your growing space, your plants will most lightly be find and happy with all that extra light. Then are you as a grower wasting energy that is not needed in all the extra lighting.

Electrical Safety is #1

Most normal wall outlets are designed to run no more then 1300 Watts per outlets. This is on a 1500 breaker. When you are picking your grow lights it is very, very important that your wall socket can handle the wattage of the light, you intended to run. It also of upmost importance that you as a grower you remember that the light will most likely not be the only thing you are running off the outlet.

Have a ventilation fan in your ten, a couple of small fans, maybe even a watering pump? Everyone of these electrical appliances will also be drawing power from the socket. Never mess with the electrical of your home, what so ever.  

Since growers are also growing in a wet environment with water keep any lighting ballasts or electrical things off the floor. You never want anything electrical to come in contact with water.

Type of Grow Lighting for Cannabis

There are many types of lighting out there in today’s market. Some of these include Fluorescent, CMH, High Pressure Sodium, Metal Halide, and LED Lighting for your cannabis plant.

Different Grow lighting for cannabis

Fluorescent Lighting

Fluorescent lighting can grow just about any type of plant. Does this mean that it is good for your grow room? Well not really. Fluorescent lighting is older technology, and therefor is not very efficient in today’s market for grow lighting for cannabis.  It will take many fluorescent grow lights in order to grow and harvest larger yields of cannabis buds.  

Fluorescent Grow Lighting

High Intensity Discharge Lights - High Pressure Sodium Lighting (HPS)

This type of lighting for cannabis has been on the market for many years and for the reason it was the go-to lighting for cannabis grow rooms. This type of lighting is primarily in the red spectrum of wavelengths. This matches up very well with the October Fall Sunlight, for the natural October Fall Sunlight. HPS lighting however is not very efficient when comes to growing plants. Most of the light that is given off my HPS light is of no use to grow cannabis plants. This extra energy that is given off by the HPS lights comes off as high heat. For this reason, HPS bulb are very hot and heat up the grow room.

Another disadvantage is that the bulbs start to dim very quickly and need to be replaced every 4 to 6 months with normal usage.

High Intensity Discharge Lights - Metal Halide (MH)

Metal Halide lighting is very similar to HPS light, in that it comes from a bulb and need a ballast to light the large light. These lights also give off lots of heat like HPS lighting and need to be replaced often. The only real difference in these lights as compared to HPS is that their light wavelength is much more in the blue wavelength of the spectrum.

HID Grow Lighting for Cannabis

LED Lighting for Cannabis

LED lighting is the new kid on the block for growing cannabis. Although it has been around for about 10 years for growers, it is only now in 2022 becoming a powerhouse in grow rooms. There are really so many benefits to use LED lighting over any of the previous lighting discussed.

It is far more efficient than Fluorescent, HPS, and MH lighting. These lights only started to match these other lighting types in the last few years. Before that HPS were the go-to lighting solutions for cannabis growers. With new more powerful LED lighting on the market this has all changed for the better.

Here are some of the great advantages of LED Lighting for Cannabis

  • LED lights are very energy efficient, when compared to other lighting types. These days LED’s can produce the same amount of light when compared to HPS and use almost half the amount of electricity.
  • Growers can hang the lights closers to the plants because they produce so much less heat this HPS Lighting.
  • Most LED grow lights will last more then 50,000 hours of lighting before needing to be replaced.
  • With less heat comes lower Air Conditioning Costs to keep your grow room cool in the summer.
  • LED lights have a colour spectrum that is designed to grow plants, and give the most amount of energy for the plants to grow.
  • You can dim the LED lighting when needed to save even more on lighting costing in the grow room.
  • Newer LED are starting to come with Wi-Fi so you can more easily control the light remotely and make sure it is operating as expected.

Using LED Grow lighting for Cannabis

In our opinion in 2022 there is really no reason to use any other type of lighting to grow cannabis. Most growers can find LED lighting that can fit their needs and their budget.

We recommend that grows purchase the largest grow light they can afford, making sure that it can be dimmed down to the level of light that is needed for the cannabis growth cycle.

Cannabis LED Lighting Cycle in the Grow Room

When growing cannabis, the most important thing is controlling your light with a timer for different stages of growth. When the plant geminates till the time that it starts to flower you will want to use 16 hours on and 8 hours off lighting schedule. This will keep your plants growing in a vegetative state until you are ready to flower your cannabis plants. Depending on how powerful your light is, you can dim it down from 50% to 60%. Not as much light is need in this stage of Cannabis growth.

When the grower is ready to start to flower their cannabis, they should turn their LED lighting up to 100% light output on the dimmer. The plant will require much more bright light for this period of growth.  The grower can also change their lighting timer to 12 hours of light and 12 hours of darkness to start the flower process for their plants. This cycle of lighting to flower cannabis is referred to as “forcing”.

How Far should you grow lighting for cannabis be away from the plants?

There is a very fine line with the distance that your growing cannabis should be away from the growing lights. On one hand if your lights are hung too far from the plants you will not be getting the maximum amount of light that the plant can make use of. This will cause the plant to stretch up to the light making it talk and lanky. Once the plant starts to flower, it will fall over very easily with heavier buds.

Distance of light from Cannabis Seedlings

Generally, growers can place seedling directly under their growing light. Keeping them under a little more power grow light will help them, so they don’t stretch looking for lighter. Growers should keep in mind that, too much light too close, with too much heat will damage or even kill young cannabis seedlings.

Distance of Light for Vegetative Plants

Vegetative cannabis plants can handle light than seedlings, as well as, more heat. Once the plant has formed it’s first set of true cannabis leaves you can start to provide more lighting to keep the plant growing healthy and strong.

During this period of growth many growers like to bend and twist the plant to make the top of the plants even with the grow light. This is what cultivator’s referrer to as Low Stress Training of the cannabis plant. Your goal with this is to have all the plants receiving the same amount of lighting for the next stage, and most important stage of growth.

Spacing your plants when lighting for Cannabis

Keeping your plants, the right distance from each other is another factor in making sure your plants are all getting the best light they can in the growing space.

Indoors you have limited space for each plant, and every plant needs to get an adequate amount of light to grow the best that it can. If you place the plant too close together many of the leaves will not get enough light. As the plant uses light for energy you will be taking away the plants energy to grow more leaves, old leaves will yellow and die.

This is why growers never plant their outdoor plants under trees. You will want each plant getting a very uniform amount of light. This is the reason that many growers when growing using LST methods will trim all the leaves and bottom branches from the plant. They will not receive enough light if there is a thick canopy above them.

Grow Lighting for Cannabis

Using Reflective walls for better light distribution

When using horizontal grow lighting, you are looking to maximize your grow room lighting so the plants can get even more lighting. There are many different types of reflective material that you can use in the grow space. If you grow in a growing tent this is already taken care of for the grower.

As a grower you will never want to lose any extra light that you can use in the room to grow bigger plants and the largest harvest of buds. There are many different types of materials you can use to create a more reflective room. Some of our favorites are mylar, panda foils, flat white plastic with a black backing, and tent material.

When you use any of these reflective materials it is important to make them flat on the walls. Leaving ripples in the materials can cause the light to reflect consistently in on spot in the root. This creates what growers call “hot spots” in the grow. These hot spots will reflect the light on one plant, and will end up burning the plant.

Hanging your Grow Lighting for Cannabis

Depending on what grow lighting you purchased, it can be very heavy to install. It is of the upmost importance that you secure the grow light properly. Not doing so can have devastating consequences for your cannabis grow.

Remember if this light comes down, the best case is that your plant gets crushed. Worst case if that big hot lighting comes down when you not home, it starts a fire.

Back a few years ago you could buy cannabis growing tents, that came with plastic corners for the tent structure. After a few months these would become brittle and fail. Please make sure your light is never going to come down ever.

What are Lumens when it comes to Lighting for Cannabis?

Unlike light spectrum and light colours, lumens have to do with the brightness when it comes to lighting for cannabis. Some growers confuse wattage and lumens. Wattage is the measure of electricity that light draws from the wall socket. Lumens is the measure of brightness of the light. With the introduction of high-powered LED lighting with lower watt growers can no longer rely on wattage as a good measurement of light brightness.

How are Lumens measured when it comes to grow lighting?

Lumens measurements are in the metric system and are defined by square meter of a lux. Like with all lights this is equivalent to “foot candles” of light give off. So, the more lumens a light gives off in a square meter the brighter that light will be for growing cannabis.

This gives the grower, consumer a measure of total amount of light that is visible.

How much on average does great grow lighting for cannabis cost?

Well like anything you pay for you “get what you pay for” when it comes down to buying cannabis growing lights. You can pay anywhere from $50 to $2500 for a top-of-the-line LED lighting solution.

Growers can pick up other types of lighting much cheaper. With HID lighting you can pay only $150 for a complete grow lighting kits for your plants. However, these lights are energy eaters so you will make up all the extra costs on the back end instead of the front end like with LED’s.

Conclusion

We hope that this guide will help you when you are looking to buy grow lighting for cannabis. Unlike outdoors your grow lighting indoors is one of the most important things in the grow room. With any indoor grow lighting you are looking to mimic the best lighting you can get, the sun.  

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