Growing Autoflowering Cannabis Seeds [Guide]

Understand the process!
Nicole Richter Nicole Richter / Updated on June 10, 2019

Growing Autoflowering Cannabis Seeds

Although autoflowering seeds are classified as a relatively new phenomenon, strains of this nature are descended from a hemp strain called Cannabis ruderalis, which was grown in Russia over 70 years ago. These strains are different from traditional – or ‘photoperiod’ – plants, which don’t begin flowering until they receive certain signals from the sun to show that winter is approaching. As a consequence, they require specific light schedules. For instance, it is normal to transition from a 16-8 light cycle to 12-12 to induce flowering.

In contrast, Ruderalis plants don’t need a signal – they begin the flowering process within four weeks regardless of the light/sun schedule. Within a few months, the buds are ready to harvest. Alas, these plants also contain low levels of THC, but one breeder realized that the auto-flowering capability of these plants, complete with their short growing period, could be extremely useful for home growers.

This individual began mixing Ruderalis plants with regular strains to boost potency while maintaining the ability to autoflower. Today, growers from around the world are seeking autoflowering seeds for three specific reasons:

  1. They are smaller and easier to grow clandestinely.
  2. They grow remarkably quickly, offer outstanding yields for their size, and are more resistant to diseases and pests than most cannabis strains.
  3. They are ready to harvest within 10 weeks no matter the light schedule due to their genetics.

As a result, growers are presented with a unique opportunity to grow weed fast, so if you’re interested in how to grow auto-flowering marijuana, continue reading our guide.

What is Autoflowering Cannabis?

As the name suggests, autoflowering marijuana strains flower automatically rather than waiting for a specific light cycle. In most cases, they begin flowering after a short vegetative period of 1-4 weeks. In contrast, a typical cannabis plants’ life cycle is influenced by changes in sunlight exposure. As a result, growers can easily alter the growth to their needs. For example, you can force a plant to enter the flowering stage by exposing it to 12 hours of uninterrupted darkness every night for a couple of weeks.

One of the primary reasons for choosing autoflowering seeds is to enjoy more than one harvest a season. Remember, it takes just 10 weeks to harvest from the moment you use an autoflowering seed. However, it is important to note that it is very different from other marijuana types when it comes to the harvest. An autoflowering cannabis plant is smaller than its traditional counterpart, which means the yield will also be smaller.

Although it is possible to yield up to four ounces of bud per plant, 1-2 ounces is far more common, especially if you start with poor genetics or have a low-quality lighting setup. While these plants flower automatically, they still need a minimum of five hours’ worth of sunlight a day.

How to Grow Autoflowering Cannabis Strains

Even when using autoflowering cannabis seeds, it is important to ensure your plants have as much support as possible throughout the process. Autos are more convenient but also offer far less room for error than typical marijuana plants. Ideally, you will begin your autoflower grow indoors with artificial lights you can control. This tactic reduces the likelihood of error and increases the possibility of a strong start.

Autoflowering marijuana seeds

It should go without saying that proper germination is pivotal to the healthy development of your autoflower marijuana plants. You can go down the traditional route of using soil or else you can try a container with no growing medium. The paper towel method is probably the easiest way to germinate your autoflower seeds.

All you have to do is take your seeds and place them in a moistened paper towel on a plate. Cover them with another plate to ensure moisture remains locked in. In most cases, the seeds should sprout in 1-4 days, although older seeds could take up to a week.

Create a small hole in a moist growing medium up to an inch deep. Transport the sprouted seed root down into the hole and make sure not to touch the root with your hands. Ideally, you won’t transplant them again, because autoflowering seeds are susceptible to transplanting shock.

Avoid early cuttings with autoflowering marijuana strains

We don’t recommend taking cuttings during the early growth stages of autoflowering weed. As the plant will autoflower at a specific point, the age of the cutting will merge with the age of the parent plant. In other words, they will flower at the same time. Therefore, if you grow a cutting of an autoflowering plant, the final version will be significantly smaller than the parent when it reaches the flowering stage.

Training your autoflowering weed

It is best to complete the training process during the vegetative stage. It is important to act fast because this stage is only a couple of weeks long in autos. We recommend using a Low-Stress Training (LST) method such as pulling the plants down sideways to help boost upwards growth. When they start flowering, prune them for up to a week into the flowering stage and do NOT top them.

You can’t prune an autoflowering plant in the same way as its traditional counterpart. First and foremost, all pruning should begin early in the life cycle or else you risk hindering its growth.

Best lighting & climate for autoflowering marijuana plants

The fact that you’re allowing plants to flower when they should be in the vegetative growth stage means you can autoflower rather late in the season (September) or very early (March). If you go down this route, please note that the plants require warmth to grow, and exposure to excessive levels of moisture could result in rot. As a result, we recommend growing autoflowering plants indoors if possible. Ideally, your plants will grow in a room with a temperature of 73 degrees Fahrenheit with 55% humidity.

You have a little more freedom with light scheduling. For example, you could try to expose the plants to 24/7 light to boost growth or follow an 18 hours of light, six hours of darkness schedule to give them a little rest. Experienced growers tend to go for a 21-3 light cycle using 120-Watt LED lights for the first few weeks. Keep the lights 70-80 cm away from the plants. Eventually, change to bigger LED lights and an 18-6 schedule.

Feeding your autoflowering weed plants

As autoflowering plants are small and grow for a relatively short time, you don’t have to go wild with feeding and nutrients. Ideally, you will avoid adding any nutrients (barring some Root Stimulant) for the first 2-3 weeks. By the pre-flowering stage, you can add some supplements such as Grow, Bloom, and molasses to the mix. By the budding stage, slightly increase the amount of Bloom and reduce the amount of Grow.

Remember, the short vegetative cycle means you need to take it easy with the Nitrogen. Overall, light feeding is the best option. Also, it is ideal if you avoid switching to flowering nutrients until you notice that the plant’s vertical growth has halted.

How to harvest autoflowering marijuana plants

Experts recommend harvesting your autoflower plants sequentially, which means taking the colas first. This process allows the lower buds to grow a little before they are harvested. As you’re doubtless aware, the yield depends on the length of the growing cycle. All things being equal, a plant that takes 12 weeks to grow should provide more bud than one with 10 weeks’ worth of growth.

It is normal for a strain that grows for three months to offer approximately 40 grams per plant, for example (almost 1.5 ounces). However, if you find a ‘super’ autoflower strain and grow it outdoors for longer, you could produce an incredible 500 grams per plant!

Generally speaking, you should consider harvesting when at least 50% of the plant’s trichomes have turned amber. If you wait too long, the plant will lose its potency. One important tip is to stop watering your plants 24-48 hours before harvest to ensure added nutrients go away.

Curing & storing autoflower weed strains

Many of the same drying, curing, and storing rules apply with autoflowering cannabis plants. You can dry your buds by hanging them upside down for a few days. Store them in airtight containers but ensure there is a bit of space in each jar. Initially, open the jars once a day for a few minutes.

After a week, opening the jars once every 2-3 days will suffice. Your bud is ready for use once there is only a small amount of moisture left. Transport your weed to a sealed container and use it within a few months.

Where to Find Autoflowering Cannabis Seeds

It is relatively easy to buy autoflowering seeds online. There is an increasing number of reputable websites that sell autoflowering seeds. Alternatively, you can find them in a local dispensary, but purchasing the best autoflower seeds can be a challenge at first.

When making the decision, ask yourself the following questions:

  • What level of THC and CBD are you looking for?
  • What is your preferred taste and aroma?
  • What kind of growing conditions will the seeds be planted in?

It is also crucial to purchase feminized seeds. Otherwise, around half of your crop will consist of male plants which could ruin everything. If you have a small grow room, purchase an indica strain because they are much smaller. If you have a larger space, buy sativa autoflower strains because they are bigger and provide a greater yield.

The Pros and Cons of Growing Autoflowering Cannabis Seeds

While it may seem like a no-brainer to grow autoflowering marijuana at any chance you get, there are of course some disadvantages that come along with the host of benefits that autoflower weed strains provide. Here is a brief list of pros and cons for autoflower marijuana vs. regular marijuana:

Pros of autoflower marijuana strains

Greater Variety

The shorter growing season means you have a greater level of autoflowering varieties. Imagine having the opportunity to grow three different strains in a single season! Multiple harvests are especially useful if you enjoy the growing process and are keen to sample as many marijuana types as possible.

Uncomplicated Setup

If you grow marijuana the traditional way, you’ll typically require a specific growing room and a separate flowering room. With autoflowering weed, you only need a single space. If you have several rooms, you can time your growing to guarantee a harvest every few weeks.

If you grow in the typical manner, you have to ensure your grow room has light-proof sealing. It is a disaster if this gets breached. In contrast, a light leakage has no discernible impact on the flowering stage of your autoflower marijuana.


As autos contain Ruderalis genes, they are tougher than other marijuana plants. Remember, they are based on plants that were able to grow in the harsh Russian weather conditions. If there is a power outage, a normal cannabis plant will have its flowering and growth phases interrupted, which could play havoc with their growth cycle; this is not a problem with an autoflowering plant.

Cons of autoflower marijuana strains


Although you benefit from faster harvesting, autos are less efficient than their photoperiod counterparts regarding light used per gram of harvested bud. This is because autos require the same amount of light per plant than typical weed but produce a lower yield on average.


A feature of autoflowering plants is the differences in size and speed of growth, even within the same strain. As a result, using a hydroponic growing system is virtually impossible. In some cases, you’ll have to harvest a single crop several times until every plant is harvested.

Final Thoughts on Autoflowering Cannabis Strains

The process of using autoflowering marijuana plants is becoming increasing popular. It is a technique that enables you to harvest from a seedling within 10 weeks, and you only need a relatively small space to begin. They are more robust than their photoperiod rivals, and significant improvements in the development process mean that these plants are also producing more potent marijuana.

However, auto-flowering plants are small and produce a fraction of the yield associated with traditional marijuana. Although you don’t need to stick to a rigid life cycle, your autos still need a lot of light to thrive which results in an extremely steep electricity bill. While you can grow stealthily, the enormous energy bill could attract unwarranted attention depending on where you live. If you live in a state where it is legal to grow marijuana, perhaps you can try autoflowering plants because they enable you to try several new strains each year.

  1. Maricica S
    For the noobs

    I grew 2 auto strains last summer as a noobie grower. I cold stressed one plant by transplanting to early in north central montana. The weather is favorable for outdoor growing beginning in July. I got a hermie plant along with some average smoke. Ill do better next time.

  2. WeesterMcFly
    Outdated/Biased Information used in this ARticle

    This is referencing first generation strains not the newer strains which have comparable thc content and larger yields. Some have even quicker grow/flowering times than the first gen.

  3. Gabriel

    Some info of this article is not updated

    1. Jana Medley
      Some latest strains?

      Although not updated, I am going to research more as you are saying, but if a newbie or novice like me reads it, we feel it is easier to understand and to have a base where to start from for auto-flowering seeds and strains. Can you suggest me some latest strains of 2019 that can be grown as auto-flowering, and what are the best weather and lighting conditions required for the same?

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