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Types of Lights to Grow Autoflowering Cannabis

What lights are simply the best to grow autoflowering cannabis? Read on to find out...
31 December 2019
6 min read
Types of Lights to Grow Autoflowering Cannabis

Growing cannabis is genuinely satisfying, but since there are restrictions in many places, you’re forced to go indoors. In these situations, lighting plays a major role. Thus, we present to you the types of lights to grow autoflowering cannabis.

If you’re growing autos, you need to focus a lot on the lighting. Compared to photoperiod varieties, autos need your attention when it comes to light. Why? Because autoflowers have a short life. They grow and produce buds that can be harvested in just under 2-3 months. With such a short span of life, you cannot afford to make the plants weak by providing cheap lighting.

 Adding to the dilemma of an autoflowering cannabis grower, you have just too many options out there today. CFL, HID or LEDs? While some say that CFLs are just enough for autos, those that use LED will completely disagree. Obviously, LEDs are stronger than CFLs, but what’s really best for autos?

ThatoneAKGuy pineapple-express

Do autoflowers need strong lights?

Autoflowers will grow nice even with 12/12 lighting, so why do they even need strong lights, you ask? Yes, the question makes sense. But, think about it – if they’re going to get only 12/12 hours of light every day, don’t you think it’s imperative that they get light that’s as good as sunlight? Also, autos that get about 18 hours of light and 6 hours of darkness from the beginning to the end perform better than those with minimal lighting.

Point is that autos will grow even in a 12/12 cycle, but if you want stunning yields, you’ll have to provide more light. Plus, strong lights are a must. As long as you’re not trying to reduce costs, using weak lighting doesn’t make sense.

Best types of lighting used for autoflowering cannabis

  1. CFL

CFL Grow light

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Unless you’re growing in a closet, CFLs should never be your choice. However, we are including it in the list here because it’s one of the options if you choose to grow marijuana stealthily. Additionally, there’s no other lighting that can beat CFLs if you don’t have a lot of space.

Also, CFLs are available everywhere. And, they are cheap to beat. You’ll need to use two different types of CFLs for the growing and flowering phase, though. For instance, if the plants are in the vegetative stage, you’ll need daylight CFLs whereas CFLs emitting warm light will be perfect for the flowering phase.

One drawback of using CFLs in bigger grow rooms is that you’ll have to use many CFLs to provide enough light to the plants. They aren’t very strong either, especially if you compare them with LEDs and HIDs.

2. Fluorescent lights


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Fluorescent lights – also referred to as T5 lights by some – are great for autoflowering plants. They aren’t very strong, but the plants grow decently as long as you provide many sets of lights. Like CFLs, you will need to purchase more lights.

T5 lights work well for the plants during the vegetative stage, but they don’t serve the purpose during the flowering phase. For this very reason, most growers prefer other lights.

3. HID

HPS Image Source -

HID lights are arguably the strongest in the market. They are sturdy, strong, and last a long time. Most HPS lights work very well for at least 20 to 24000 hours. Once the bulb stops working, you need to replace them. You can use Metal Halides during the vegetative phase; however, you’ll have to switch over to HPS lights during the reproductive stage because MH lights don’t work too well when the plants are flowering.

 You have to understand that you have to switch lights since you need to replicate the seasons. The main reason to not use MH during flowering phase is that they produce a lot of blue light. An abundance of blue light during the vegetative phase is amazing, but it becomes a hindrance during the flowering period. It also produces airy buds instead of yielding resinous, dank buds.

What is perfect during the flowering phase are HPS or high pressure sodium lights. They produce loads of yellow light that most cannabis plants love specially when they are flowering.

CBD Auto 201
5 out of 5
I have grown this 3 times now and I always like the result. Each time it has grown slightly different, but I find the effect is always the same.
Verified customer
Reviewed 4 June 2020

One advantage of using HIDs is that they are cheap and available almost everywhere. However, due to the amount of power they consume, you may find the electric bill a little too expensive for your taste. If budget isn’t a concern, using a combination of MH and HPS lights is the best lighting you can provide while growing autoflowering cannabis.

A word of caution if you’re using HIDs, though. Since they produce lots of light, they tend to heat up quickly. Thus, you have to pay attention to the ventilation. Purchase high-power fans that prevent the tops from burning. Fans will also reduce the heat and you’ll prevent any chances of a mishap.

4. LEDs

Autoflowers growing in 83W LED light

In this picture above, 4 plants are growing under an 83W LED light!

LEDs or Light Emitting Diodes are the best lights to grow autoflowering cannabis without a doubt. Honestly speaking, LEDs are perfect to grow any kind of marijuana. Although you don’t need to switch light and dark cycles for autoflowers, most LEDs come with an option to do so. This way, you can even save some money by saving power.

Tangie Auto
5 out of 5
Dense nugs cooovered in trichomes. The aroma that comes off this strain is wonderful. Nice uplifting and motivating high.
Verified customer
Reviewed 23 June 2020

You can use LEDs to your advantage by providing blue light in the vegetative phase and then switching to red lights during the reproductive stage. Even smaller LEDs are now available with this option.

LEDs are a wonderful combination of most types of lights mentioned here. Want to grow in the closet? You can purchase smaller LEDs that fit snugly in the closet. Have a big grow room? Get one of those swanky lights with a range of power from 300 to 2000W. Yes, you can go as far as 2000W! And, talking of power, you will be worried about the electric bill. But, thank goodness for LEDs because they don’t consume a lot of power at all!

The best part of using LEDs is that they don’t heat up unlike other powerful lighting equipment. They are sturdy and last longer than 100,000 hours! Yes, you read that right! These beautiful babies last so long that you’ll not have to worry about replacing them. This also means that you’d have to replace at least 5 HPS bulbs in the amount of time taken by an LED! Imagine all the money you could save!

Blackberry Auto
5 out of 5
Grew blackberry in my past 3 runs, love the Fruity berry smell and taste. Everything I grew it always comes out purple buds.
Verified customer
Reviewed 9 July 2021

Earlier, LED lights were super expensive, but they are cheap now thanks to technology. You can even get LED strips to cover any area that doesn’t get a lot of light. Most LEDs also come with fans attached so heat will not be a problem. To take it up a notch, you can use COB LEDs that are the most powerful of all LED lights. Usually available as single lights or in pairs, COBs emit so much light that it’s difficult to even look at them without safety goggles! Many LED companies also offer safety goggles because of the intensity of light, so you don’t have to worry about purchasing them separately.

In conclusion, after comparing most types of lighting you can use to grow autoflowering cannabis in particular, you can safely say that LEDs are best. Due to the features, power, and lifespan it offers, you can be sure to grow some big buds oozing with a lot of resin.



31 December 2019