Why are Grow Lights Important?
Grow lights are important to simulate the natural passing of seasons. This allows marijuana plants to be grown indoors at any time of the year in a contained, controlled environment.
In nature during the summer season, marijuana plants focus their energy to rapidly produce leaves and roots, this is called their vegetative stage.
This is replicated indoors by turning on grow lights for a longer duration of the day.
During the fall season, the marijuana plant enters its flowering stage. The plant’s energy is now focused on producing its fruit, known as sticky buds.
This cycle is simulated by shortening the amount of time the grow lights are left on during the day, thus giving the plants a longer period of darkness.
In the vegetative stage, you need to replicate the long days of summer. This can be done by leaving the grow lights on for the majority of the day. A common light cycle for the vegetative stage is 18 hours on and 6 hours off.
Allowing the plant to achieve longer periods of photosynthesis, therefore producing enough food for the plant to consume during its rapid root and leaf development.
Some growers prefer to leave the lights on for a 24 hour period. This is typically done using fluorescent or led grow lights to reduce the chances of heat burn.
In the flowering stage, the plant begins to produce its fruits due to the shorter days of fall. This is triggered indoors by reducing the duration of lights being on. Most growers prefer a light cycle of 12 hours on and 12 hours off.
It is important to keep your grow area completely dark during the lights off hours. If you need to work on your indoor garden during the dark period, you can use a special green light that will allow you to see but will not disturb the marijuana plants.
Types of Grow Lights
The 3 most common types of grow lights are High Intensity Discharge (HID) grow lights, Fluorescent grow lights, and LED grow lights. The new kid on the block, Plasma grow lights, show promising results but not enough documented grows to justify its high costs.
You need to do research when deciding on which grow light to purchase. There are many pros and cons to each system and you need to figure out what works best for you.
HID Grow Lights
Most growers consider HID grow lights to be the “holy grail” of grow lights. Known to produce some of the highest yields when compared to all other grow light systems. HID systems come in various wattages from 150 watts up to the most commonly used 1000 watt system.
Metal Halide grow lights are best used for the vegetative stage because it produces a bright cool light spectrum that the plants need during the summer season. HPS grow lights, on the other hand, produces a warm light spectrum that is perfect to simulate the fall season, allowing the plants to enter its flowering stage.
When deciding to purchase an HID grow light system, it is advised to purchase a light system as a kit or package. This way, you can ensure that your bulbs, ballasts, and hoods are all compatible with each other.
Although HID grow light systems receive rave reviews for their incredible performance, you need to consider the cons for having such a high performer.
These light systems are able to push out powerful light, which help your overall yields, however they also require more energy to power those lights. Having a higher than normal utility bill should be expected when using these systems.
The biggest negative of HID lights, in my opinion, is the amount of heat that they generate. Being able to control your temperatures during a grow is hugely important, especially during the flowering stage. Having too high temperatures can destroy your entire indoor garden.
One way to combat high heat is to make sure you have enough ventilation and air flow. Some HID systems even have air ducts that allow you to extract the heat directly from the hood of the light with an inline fan.
Another popular method is using air conditioners inside your grow room. We will leave this method for another article.
So if you don’t mind paying extra in utility bills and have an efficient way to control your temperatures, using a HID grow light system is a the way to go.
Fluorescent Grow Lights
Using fluorescent grow lights is a great and inexpensive option to choose, especially for beginners. You can use fluorescent lights throughout the entire grow, or just using them during the vegetative stage.
It is known that your yield may not be as great as using HID grow lights, but if used correctly, high output fluorescent grow lights have the ability to produce some of the most dense and potent marijuana buds.
The most popular forms of fluorescent grow lights are Compact Fluorescent Lights (CFL) and high output T5 grow lights.
Compact Fluorescent Lights
Using CFL bulbs are a great way get your indoor garden established when you first start growing marijuana. They are very inexpensive, create very little heat, and can be purchased at almost any store. They come in different color spectrums that allow you to use CFLs throughout the entire grow cycle.
The vegetative stage will require “daylight” (6500k) CFL bulbs, while the flowering stage requires “soft white” (2700k) CFL bulbs. This will supply your marijuana plants with the full range of light spectrum it needs to thrive. You can also purchase clamp reflectors to help distribute the light and allows easy placement inside your grow room.
Normally, CFL grow lights are only used when growing just a few plants. These bulbs have the capability to produce a lot of light, using very little energy. CFL grow lights are also perfect for seedlings and clones.
The downside to these bulbs are that they are not as powerful and must be placed extremely close to the plants in order to provide sufficient light. Unlike HID lights, CFL lights can only penetrate about a distance of 1 foot from the bulbs.
To provide the lower parts of the plant with enough light, you must place the bulbs no more than a few inches above the plant. There are also several plant training techniques that allow you to grow the plant very short and flat. This is beneficial for fluorescent grow lights because it maximize the light coverage.
T5 Grow Lights
Modern day high output T5 grow lights are pretty much amazing and can produce some very high quality marijuana.
The initial comment you will hear from grow forums is “they are only good for veg”, which is far from the truth. They are great for the vegetative stage, however, they also perform incredibly well for flowering your marijuana plants.
If used correctly, T5 grow lights produces very dense and potent marijuana. Just like CFL lights, T5 grow lights can only penetrate about 1 foot from the bulbs. This means that you need to properly train your plants to grow short and flat to give the best light coverage.
The trick to T5 grow lights is to keep the bulbs as close to the top of the plants as possible. Since they create very little heat, the plants can almost touch the bulbs without burning.
There are many training techniques that you can use but my preferred method is known as the ScrOG (Screen of Green) training technique. With the ScrOG method, a flat net or screen is place over the plants. When leaves and stems grow above the screen, you pull those down and tuck them back underneath the screen. Repeating this process until the screen is filled and you are ready to flower.
This gives you the perfect flat canopy to place a T5 light system a few inches above the screen. Maximizing the light exposure and producing many dense marijuana buds. This differs from HID light systems because instead of growing one giant cola, your goal is to produce many smaller and more potent colas.
LED Grow Lights
LED grow lights have recently advanced in technology. These lights are far more efficient at consuming energy and generates almost no heat. The idea of LED grow lights are great, allowing individuals to grow in small closets or cabinets without needing to worry about high temperatures.
They do work, and work well, but they have not advanced to the point of dominating the grow market. Unfortunately, LED grow lights cannot compete with HID systems or even T5 grow lights when it comes to high yields.
When choosing an LED grow light, it is very important to purchase your light form a trusted manufacturer with good reviews. There are many LED light systems out there that flat out do not work. Be cautious when you see a LED grow light systems at a bargain prices. When it comes to LED grow lights, you really do get what you pay for.
If heat and energy bills is top priority on your list, then choosing a LED light system is a great option.
Best Grow Lights?
There is no correct answer for this questions. You need to make the decision for yourself based upon what grow environment you can provide.
If you are after the biggest yield, then HID grow lights would be the system to go for. However, if your grow room is small and you cannot control the heat generated by HIDs, then you are setting yourself up for failure and disappointment.
LED grow lights are great for heat control and is easy on the energy bill, so if that is important, you should go for LEDs. Just be aware that you need to purchase quality LED grow lights and be satisfied with a smaller overall yield.
T5 grow lights are really the best of both worlds. It generates much less heat than HID grow lights but are capable of producing really high quality buds. If you are just starting your journey of growing marijuana, I would highly recommend choosing T5 grow lights.