Cannabis plants come in many different varieties. You may have seen them whilst shopping around for cannabis seeds. There are two main types of cannabis plants you will find on most seeds banks: Feminised, which are photoperiod cannabis plants, and ‘Autos’, which are autoflowering cannabis plants.

In this guide, we will explain the difference between these different types of cannabis varieties, with a main focus on autoflowering cannabis plants. This way, you can make a well informed decision on what type of cannabis will be best for you to grow.

If you have any questions as at all about auto flowering cannabis plants, feel free to ask for help in our cannabis growers forum. We are always happy to help.

Contents

Main Types of Cannabis Seeds

If you are new to growing cannabis, you will be browsing the seed banks, looking at your favourite strains, and wondering which one you should buy.

First we will discuss the main 2 types of cannabis seeds, photo period, and autoflowering cannabis plants.

Photoperiod Cannabis Seeds

Photoperiod cannabis plants, will grow differently, according to how much light, and how much darkness they get per day. This is known as a light cycle.

A cannabis plant, has 2 main grow periods, the vegetative period, and the flowering period.

If a photoperiod cannabis plant is given around 18 hours of light, and 6 hours of darkness per day, it will stay in the vegetative stage. This is when the plant will grow leaves, stems, and branches, but no flowers.

By controlling the light cycle, and keeping a canna-plant under 18/6, you can keep it in veg and let it grow as big as you like before flowering.

A photoperiod cannabis plant will not go into flower until it receives around 12 hours of light, and 12 hours of darkness every day. This is known as 12/12, and most growers will use this light cycle to flower their photoperiod plants.

Learn more about different types of light cycles for photoperiod cannabis plants on Percys Grow Room.

This guide will give you an understanding of why photoperiod plants grow the way they do.

Autoflowering Cannabis Seeds

Auto flowering cannabis plants are a little different from photoperiod cannabis plants. Unlike photoperiod plants, autos will flower under any light cycle, 12/12, 18/6, and even lights on for 24 hours a day.

When you germinate an autoflowering cannabis seed, you have a set amount of time until harvest. You can not extend the life cycle like you can a photoperiod plant, as you cant keep autos in veg, they will flower automatically under any light cycle.

Also, you can not clone autoflowering cannabis seeds, once the seed is popped, harvest time will arrive within 10-12 weeks on average.

Most auto seeds will be feminised, as male plants are rarely wanted by a Percy Grower, unless you are thinking about breeding.

Regular Cannabis Seeds

Regular cannabis seeds are photoperiod plants, and each seed is either male or female. You will not know the sex of the plant until it has begun to flower.

In most cases, a male cannabis plant is useless to a grower unless they intend to breed their own strains. The pollen will be released, and then pollinate your female plants.

This will cause seeds to grow in your buds, so males are not usually wanted around the grow room.

Regular seeds are good for breeders, or growers looking for a good mother plant for cuttings. Most growers today, will opt for feminised seeds.

Feminised Cannabis Seeds

Feminised cannabis seeds come in photoperiod, and autoflowering form. These seeds will grow female cannabis plants 99% of the time. This is good for growers, as they do no need to waste space on more plants than they need, because they will not have male plants in the grow room.

If you are planning on growing a few plants, and you have limited space, then feminised seeds will be your best option.

Choose a feminised photoperiod strain, or a feminised autoflowering strain, this will pretty much guarantee you buds with no seeds. You just have to look after the plants well and keep stress minimal, especially during the flowering cycle.

What are Autoflowering Cannabis Plants

You may have heard of different types of cannabis, Indica and Sativa. These are the main 2 types of cannabis, but there is a third, that is not as well know, called Ruderalis.

The ruderalis, is a type of cannabis native to Siberia, and the Northern Hemisphere. It was noticed that the ruderalis would flower in a set time frame, regardless of how much light it received. The problem was the ruderalis did not produce a lot of THC.

The genes of the ruderalis were crossed with indica and sativa strains, so over time the genetics were stabilized. This is what brought us autoflowering cannabis plants. We now have autos with high THC and CBD, that can be germinated and harvested in just ten weeks!

This is what brought us autoflowering cannabis plants. So we now have autos, with high THC, and CBD, that can be germinated, and harvested in just ten weeks!

Light Cycles for Autoflowering Cannabis Plants

Autoflowering cannabis plants can flower under any light cycle, so most growers will take advantage of this and give the plants at least 18 hours of light per day. In some cases, growers will give their autos 20 hours of light, and just four hours darkness- some growers even opt for 24 hours of light for the life cycle of the plant.

As a plant uses light to make food, the more light a plant receives, the bigger it can grow. But plants do need to rest too. Though growers see great results under any light cycle, you should grow your autos under at least 18/6, and a maximum of 20/4

Pot Sizes for Autos

There is controversy behind this topic, like there is with a lot of cannabis growing techniques.

You see, with autos, you germinate them and there is a set time you have until the plant is finished. Any stress can slow the growth of the plant down, and this will in turn affect the final yield.

Because of this, some growers choose to start their autoflowering cannabis plants in their final pot. Transplanting a cannabis plant from one pot to another can damage the root ball. This is a huge amount of stress to a plant, and it can take a few days to a week to fully recover. With autos, you don’t have that much time to waste.

An auto flowering cannabis plant should finish in a pot around 10-12L. This is fine to start in, but you can also start in a smaller pot and transplant once.

Either start in a 0.5-1L pot, and transplant once, or start off in a 10 or 12L pot, and do not transplant at all.

As long as you’re careful, and you do not stress the plant during the transplant, everything will be fine. It is your choice.

Topping and Trimming Autoflowering Cannabis Plants

Because topping and trimming a plant will cause stress, some growers recommend you do not top autoflowering cannabis plants.

In my opinion, any plant that is grown indoors should be topped. It will help you get a better spread of light, and stop the plants growing too tall.

If you are going to top your autos, you should do so at the third node, and early on in the grow stage so the plant can recover quickly.

Topping a Cannabis Plant Find out how to top a cannabis plant correctly, here.

How Long do Autos Take to Grow

On average, it will take between 10 and 12 weeks from when you first germinate a seed, to the day you chop the plant down. This will be strain dependent, and you will find it in the information section of the strain in your seedbank.

Some autoflowering cannabis strains will take up to 16 weeks from germination to harvest, check with the breeders information before you buy the strain.

Each plant is different, and the breeders date, is a simple guideline. You have to watch the trichome development of a plant to know if it is ready for harvest or not, any time scale given is just an estimate.

When to Harvest Autoflowering Cannabis Plants

The best way to tell if your cannabis plant is ready for harvest is by checking trichomes on the buds of the plant.

The trichomes are the small THC crystals. You should use a jewelers loupe, or a usb microscope, with at least 60x zoom, to get a good look at their progression:

Click to Expand

Clear Trichomes:

The plant is not finished and the THC is immature. Harvesting now will reduce final yield and potency

Milky Trichomes:

THC is at its peak, and harvest time approaches

Amber Trichomes:

THC has passed its peak, and is now degrading, harvest anytime. Amber trichomes are said to give a more “couch lock” effect, and bring you a more relaxed, heavy stone.

Some growers like a couch lock stone, some like a more euphoric high, so finding the right personal preference for yourself, will take trial and error.

You should look for at least 90% milky trichomes before harvesting. The amount of amber/milky is usually growers preference. The majority of growers like to have around 90% milky trichomes with 10% ambers.

Autos vs Photos

Deciding on whether to choose autos or photos can be difficult. They each have their pros and cons, and only you know what will work best for you.

It’s good to have options. Because photoperiod plants will vegetate under 18/6, and autos will also flower under 18/6, you can keep vegetating plants alongside flowering plants in the same grow room.

Autos and photos can be used together, there is no reason to limit yourself to either one or the other. Try both, and see what works best for you.

There is never a definite answer with growing cannabis, autos might be perfect for you and your circumstances, but they might not be good for others. There is no, “one is better than the other”, its more which one is better for you.

Harvest Time

On average, an autoflowering cannabis plant will go from germination to harvest in about 10-12 weeks, this can seem fast, but it can be matched by photoperiod plants.

A cannabis plant will need between 3 and 5 weeks, before it reaches maturity. It will not flower until it reaches this stage, regardless of whether it is a photoperiod plant or auto, male or female. After that, the flowering cycle can take from 8 to 14 weeks, some sativa strains flower for even longer.

So essentially, you can grow a photoperiod strain in the same time as an auto, but you would have to grow under 12/12. Less light means less food, and this will affect the yield compared to an auto.

Estimated Yield

Though you can get some massive yields from autos, you also get some small ones. It can be difficult to tell how much you’re going to get off a plant until it is finished.

Even a small bit of stress can stunt growth, and reduce the final yield. If everything goes well, and you have good genetics, then you can get up to 5 ounces off one auto, experienced growers can even exceed this!

Photoperiod plants will always out do autos for yield, but not in the same time frame. Because autos can have much more light during the flowering phase, they can produce more food and grow bigger.

Potency of Autoflowering Cannabis Plants

Autos will grow fast, and grow a pretty decent yield in a short space of time. However some growers do claim that they are slightly less potent than photoperiod cannabis plants.

Light will degrade the THC on your plants, and autos will get 18 hours of light a day during their flowering cycle, compared to 12/12 on a photoperiod plant. This may affect the potency of the crop, but there is no real evidence to show autos grow weaker cannabis than photos.

Autoflowering cannabis plants, can have high levels of THC reaching up to 25%! Good strains from good seed banks will grow very frosty, and there is no difference in flavour or potency.

It is very difficult to tell from the final product if the bud has grown from an autoflowering or photoperiod cannabis plant.

Best Way To Grow Autos

Don’t restrict yourself to just one kind of plant, experiment and find what is best for you!

Some growers will grow only autoflowering cannabis plants, and never grow photoperiod. On the other hand, there are growers that hate autos, and only grow photoperiod plants.

Growing cannabis is an art form, you find your own style, your own way, and only you can know the best way for yourself.

Because autos can grow alongside vegging plants, on 18/6, you can keep flowering autos, in the same room as vegetating plants. This can increase the amount of times you can harvest in a year, as you can rotate the plants as they grow.

Rotational Growing

Germinate one or two auto seeds, and four or five weeks later, when they have grown and begin to flower, pop some more seeds and add them to the grow room. Doing this will give you a harvest every 4/5 weeks, instead of waiting the full 12-14 weeks that it takes to grow a photoperiod plant.

You can also start 4 autos and 4 photos together in a 1m x 1m grow tent, under 18/6.

After a few weeks, they will outgrow the tent, and you can move the photoperiod plants into a flowering room, whilst keeping the autos in the veg room under the 18/6 lights.

When the autos are harvested, the photoperiod plants should be a few weeks into flower. This gives you time to start 4 more photos, and four more autos, and repeat the process.

Final Thoughts on Autos

Growing autoflowering cannabis plants, and photoperiod cannabis plants together, will give you more options, but you can also just grow autos, or just grow photoperiod plants. It is completely up to you!

You can get most strains in autoflowering form now, and I would recommend that you at least try growing a few before you make your mind up on whether they are right for you or not.

You can get help throughout your whole grow in the cannabis growers forum over at Percys Grow Room. So don’t be afraid to explore and try new things.

Cannabis growing is an amazing hobby, experiment and enjoy it.