Autoflowering cannabis plants are a reasonably new addition to the cannabis industry. They differ from traditional “photoperiod” cannabis plants, because they will flower under any light cycle.

For a photoperiod cannabis plant to start flowering, you must reduce the amount of light hours it gets, and increase the dark hours. Most growers will induce flowering in a cannabis plant by giving them 12 hours of light, and 12 hours of darkness ( 12/12).

An autoflowering cannabis plant, will flower under most light cycles, some even on 24 hours of light for their whole life. Auto flowering cannabis plants will go from germination to harvest, in anything from 8 – 14 weeks. Unlike photoperiod plants, they have a set time, and you cannot extend the veg period of an auto flowering cannabis plant. As soon as the seed is germinated, you have a set amount of time until the plant is finished.

If you have any questions about growing autoflowering cannabis plants, then feel free to ask for help in our cannabis growers forum

Why Auto Flowering Plants

Most growers would have heard of the different variations of cannabis. There is Indica, and Sativa. There is another type of cannabis that is less known, called the Ruderalis.

The ruderalis is a type of cannabis that grows in the northern hemisphere. It was originally discovered around 1924 in Siberia, and throughout parts of Russia. Because of the colder environment, the plants grow shorter, and are hardier than other types of cannabis.

The problem was, the plants didn’t produce good flowers, and the THC content was very low. Around 15 years ago, some growers decide to try crossing the genetics of a ruderalis with high THC cannabis strains. The plan was to create a cannabis strain, that carried both the auto gene, but also carried high THC genetics.

The first auto flowering strains were not great. But over the last ten years they have become very potent and high yielding plants. They have risen massively in popularity, and in some cases, are prefered over photoperiod cannabis plants.

Growing Autoflowering Cannabis Plants

Just like any other cannabis plant, you need to germinate your seeds. If you have done this before, than you usual germination technique will work fine. If you’re new to growing cannabis, you can learn the best to to germinate cannabis seeds by clicking HERE.

This is the only time you will treat your auto flowering cannabis plant like a photoperiod.

Planting Autoflower Seeds.

When you’re growing photoperiod cannabis plants, it is common to start in small pots, and make you way up to bigger pots as the plant get bigger. This works great for photos, as you can let your plant recover from stress with a few extra days vegetation.

Growing autos, you do not have that privilege, you have a set amount of time, and any stress will reduce growth.

The tap root of your seed will grow downwards, until it hits the bottom of the pot. Once there, it will grow out radially, and spread roots throughout the pot. When the tap root starts growing radially, you want the new roots to have as much space as possible.

Starting in a big pot will encourage your auto to grow a long tap root, and in turn, you will have a bigger root ball. More roots equals more shoots.

You can still start your autos in a small pot, and transplant once, before the flowering period begins.

Start your autos off in there final pots if you can, and you will see a huge plant in a couple of months. Starting in smaller pots is also common when growing autoflowering cannabis plants. Either way, you will still grow big plants.

What Size Pot to Use for Growing Autos

Choosing your pot size will depending on the medium you’re going to grow your auto in. A minimum of 10L is recommended, with no more than 18L if growing in coco.

Pots for growing autos in soil

Starting off in a 12l Pot is perfect for growing autos in soil. Don’t fill to the top right away, fill with ten litres first. As the plant gets bigger, you can add more soil to the top ( back fill).

The base of the stem will grow more roots when you bury it. This will increase your root space and over all size of the plant.

You can also use this pot for growing an auto in coco.

What pot to use for growing Autoflowering Cannabis Plants in coco

One of the main factors of growing cannabis in coco is to provide the plants with alot of air to the root zone. Using either a fabric pot, or an Air Pot, to get the best results when grow autos in coco.

Because your roots will use you their space more facility, you can lower the size of your pot if you wish. When growing autos in coco, you should go no lower than 10L pots, and now higher than 18L.

What Lights Cycles Work Best For Autos.

The beauty of growing an autoflowering cannabis plant is that you can choose a light cycle that works for you. Most strains will flower under 24 hours of light with no dark period. They will also flower under 12/12 like a photoperiod plant would.

Autoflowering cannabis plant growers will grow their cannabis under either 18/6, or 20/4. Giving a small period of darkness for the plant to rest. The best technique is to grow your plant under 24 hours of light all the way through vegetative stage.

When flowers start to form, reduce the light cycle by four, or six hours, that is your choice. Give the plant a little rest. There is work to be done in those dark hours, and the light will degrade your thc. To prevent them maturing too quickly, reduce the light cycle by a few hours.

What Lights Should be used to Grow Autos?

Wattage means plant growth. As you have a set time to get these plants finished, you need to hit them with as much light as possible.

Give them a T5 for their first week. But when they have a few leaves formed, hit them with the biggest light you have. See what light would be best for your grow space in our lighting guide. Make sure the light doesn’t get too close to the plant, and make sure your temperatures do not get too high.

The more light you can give an autoflowering cannabis plant, the faster she will grow. A powerful light during the flowering period will make her grow massive buds.

Should Autoflowering Cannabis Plants Be Topped?

Yes, if you are growing any plant indoors it is always in your best interest to top them. To keep a level canopy, will give your plants an even amount of light. This can only be done by topping and training your cannabis plants.

Top your auto, around the third, or fourth node, before flowers start to form. With a little training, you can double the yield compared to a plant that hasn’t been topped.

Is it Worth Growing Autos?

The genetics of some auto flowering strains will outperform a photoperiod plant in the same time frame. There is an extensive range of flavours and THC/ CBD levels to choose from too.

If you haven’t tried growing auto flowering plants, you should try it once and see how you feel. Just follow these key points, and you should do pretty well when growing autoflowering cannabis plants.

Top at the 3rd or 4th node

Train side branches and keep canopy level

Hit them with as much light as possible.

Perpetual Growing With Autoflowering Cannabis Plants.

On a final note, I would like to mention how useful it can be to simply add some auto flowering plants into your veg room. When autos are finishing on 18/6, you may have enough space to start off your next crop in the same grow room.

Because autos will grow on 18/6, using any extra space to veg your next grow saves on time, and space! If you have a small space and perpetual growing would benefit you, then autos are ideal because you will never have to change light cycle. Seedlings can live with fully flowered plants.

Start Growing Autoflowering Cannabis Plants

If you haven’t grown autos before, you should really give it a go. There is a huge selection of strains to choose from, and they can take on average ten weeks from germination to harvest!

I hope this guide is useful to you. If you have any questions or comments at all, you can come and join our community. We are always eager to help growers get to their best harvest.

There is always diversity when growing cannabis is involved. Everyone has their own way of doing things, and it all works. How do you grow your autos?

Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!

Let us know what strains you choose. Stay safe out there! Happy Growing.