How to grow autoflowers outside

When growers first get started, there can be so many questions. Every topic can lead curious cultivators deeper into rabbit holes of community knowledge. One thing that can make it easier for your first few grows is to focus on growing autoflowers outdoors instead of photoperiod plants. Autoflowers will do just that – they “automatically flower” after a certain age, typically two months, which can take some guesswork and stress out of the process. 

The benefits of Autos vs Photos don’t end there. Depending on what you’re after as a cultivator, they may be the plants for you. Autoflowers bring the advantages of a shorter life cycle which could mean multiple harvests in an outdoor season. They also come with increased resilience to light and temperature change and pests and a smaller (stealthier) footprint. Plus, the yields can be phenomenal with proper care. 

Large yields, automatic flowering and easy growing? Get your autoflower seeds now and try it for yourself!

bergman holding autoflower plant

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  • For new and experienced growers
  • Easy-growing, low maintenance
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Is it better to grow Autoflowers indoor or outdoor?

If you’ve decided autos may work for you, it’s important to consider whether you’ll be growing indoors or outdoors. For stealth reasons or those related to garden space, the decision might be made for you. If not, consider the different options carefully.

  • Full control over the environment
  • Grow year-round
  • More expensive
  • Infection spread of bugs and pests is higher
  • Cheapest way to grow
  • Sunlight will allow the plant to full potential
  • Very limited control over the environment
  • Plants exposed more to bad weather, bugs, and pests

It can be easier to start outdoors as you don’t need to maintain the environment for your plants, letting mother nature take over there. Keep in mind, nature may have other plans and throw your outdoor spaces for a loop with bad weather or drought that may need intervention.

Autoflowers can grow wonderfully outdoors; in fact, the ruderalis lineage of autoflowers helps them excel at it. They’re hearty, quick-growing plants. While not necessarily better than photos, they can be a little easier to start with. Both photos and autos will thrive outdoors with good sun and care. Some environments may not have a growing season long enough for photos, especially those with equatorial origins.

When it comes to timing for planting your autoflowers outdoors, the big thing to keep in mind is that they’ll take 8-10 weeks to complete. Some cultivars may go a little longer than that. As long as you’ll have agreeable weather for ~ three months, you can start autos outdoors. If you want to maximize your output, beginning as soon as possible may be preferable so you can get a second or even third cycle out of the same space.

Make sure to download my free Grow Bible for more advanced growing techniques for autoflowers.

What environment is best for autoflowers?

When growing autoflowers outdoors, you’ll want to pay attention to the lighting, temperature, and humidity. The optimal values for all three will depend on the cultivar (visit for plenty of excellent cultivars to choose from!). Your autos will need roughly 12-18 hours of light per day for optimal growth, although they can still flower out with 8-10 hours of light with a slight impact on yields. 

For temperature, outdoor autos will be able to survive bigger swings. Their optimal range is similar to photos – between 70 and 85°F during the day and 60-70°F at night. Autos will struggle in cooler weather below 50°F or hotter weather above 95°F degrees. 

Keep in mind humidity can be hard to control outdoors. The goal is to keep the plants between 40 and 70% to avoid drying them out or increasing the chance of mold.

Your garden may be a single plant or a whole plot of land. If you’re growing in the ground outdoors, aim to keep plants about 1 foot apart for smaller cultivars and 2-3 feet for larger cultivars. It may be worth using pots instead of growing in the ground if your space is temporary or the soil isn’t ideal. 

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The benefit of growing in pots outdoors is that you can move your plants around if needed or add more space. You can also experiment with different mediums to grow in. 

Coco Coir, or soilless mixtures, can provide a more inert medium perfectly suitable for outdoor-grown autos. This can put more pressure on selecting the right nutrients for autos. Remember to always use fewer nutrients on autos than photos because they mature so quickly you can get nutrient burn and other issues with overfeeding. 

How long does it take to grow autoflowers outdoors

The duration, intensity, spectrum, and direction of light for autoflowers outdoors can alter your grow and impact conditions. Ideally, you want as close to 12 hours a day of sun, but these plants can do fine with less. A high-intensity light is also ideal.  

You cannot avoid cloudy days and inclement weather outdoors. There may also be a need for supplemental lighting. Full sun is great for the spectrum of light when growing autos outdoors. They’ll need both blue and red wavelengths to thrive. 

Rotate your potted autoflowers to follow the sunlight

The direction of the sun is something to consider when growing outdoors. Your plants will grow towards the light, which may cause them to start leaning. Avoid this by using pots and rotating your autos regularly to balance the sunlight the plant receives

Learn the best tips and tricks to maximize your autoflower yield in our dedicated guide!

Feeding outdoor autoflowers

Nutrient requirements for outdoor-grown autoflowers can vary again based on the medium you’re growing in and the weather and environment. A broader nutrient approach is enough outdoors instead of the indoor nutrient schedule that may hyperfocus on different growth stages.

If growing in the soil, your plants will have access to natural nutrients and need even less than normal. Some nutrients are made for autoflowers. If they don’t say one or the other, they’re probably made for photoperiod plants. In this case, you’ll want to cut the recipe down by diluting it with water. 

Want to grow your own autoflower plants? Check out our collection of autoflowering seeds at ILGM.

bergman holding autoflower plant

Buy Autoflower Seeds

  • For new and experienced growers
  • Easy-growing, low maintenance
  • All popular cultivars

When choosing to grow outdoors, you can use a more relaxed or passive approach in soil with minimal nutrients or take a more active one by incorporating nutrient schedules. It may take a harvest or two to understand your environment. Spend time learning how to diagnose nutrient needs and recognize plant stress. React to any issues that arise.

Overwatering is not great for cannabis, both indoors and outdoors. Make sure to only water when the growing medium’s upper layer is dry, and take note of the weather you’ve been having. Water in cooler times of the day, and consider putting some ground cover, like mulch, around your plants outside if moisture retention is an issue. 

How much do autoflowers yield outside?

Every grower wants to know their potential yields. While general numbers can be given, your autos’ actual yield will vary depending on the care you’ve given them and the environment outdoors. When maximize yields of your outdoor autoflowers is the goal, check out our Grow Guide.  There you can learn more techniques, like proper defoliation, to help your plants best use the energy they have to create high-quality cannabis. 

The genetics you use will also limit your yields, so try to optimize weather and environment to get the most out of your selection.  

Also Read: How much yield can I expect from a single Autoflower plant?

Challenges when growing autoflowers outdoors

Autoflowers, whether grown outdoors or indoors, are typically smaller than photoperiod varieties.  However, if your plants grow slowly and stay too small, there could be a few reasons worth looking into. 

The first is the temperature; colder weather can stunt plant growth and impact yields. Over and under-watering and general nutrient deficiencies can also do it. Make sure the plants are getting enough sunlight and utilize good defoliation techniques.

Autoflower are hardy plants but not indestructible. 

There are no major vulnerabilities unique to outdoor autoflowers vs. outdoor-grown photos. Autoflower plants are generally tougher and more resistant to pests and mold. However, when their flowers are stored wrong or grown in humid conditions, they can become a problem. 

Regularly inspect plants for any signs of mold and mildew and remove the affected areas to avoid losing the plant. Do not overwater. For those growing in more humid locales, mold and mildew can be more of a problem; select your cultivars carefully.

Learn how to choose the best pot size for your autoflower plants

Germinate autoflower seeds indoors and move them outside in big pots

When starting your garden, germinate seeds indoors and allow seedlings to grow for a week or two inside before having to deal with reality outside. 

Be careful to keep your grow medium porous enough to allow good oxygenation of the root zone when it’s dried out. Some mediums can become compact over time; you can avoid this by including perlite or other materials at the bottom of your pot with soil/coco coir/peat moss on top of that. 

germinating autoflowering seeds before transporting

Make sure to start your autos in their final container; unlike photos, autos won’t need to be transplanted. Their growth period is so short you’re only creating more work for yourself, and no cultivator wants that. Check your medium pH a few times throughout the cycle to make sure it’s within 5.5 and 7. The pH level is still important outdoors as it will limit nutrient uptake if it’s out of line.

Learn more about timing your autoflower harvest perfectly with my free harvesting mini guide!

Final thoughts on growing autos outdoors

Growing autoflowers outdoors can be a solution to speed up the life cycle and harvest quicker while reducing the space needed in your garden. Newer growers can’t go wrong starting with autos to get a few harvests under their belt before attempting photos. They’re more forgiving overall and can have greater yields when done right. Be aware of the differences between photos and autoflowers outdoors, and research anything that comes up here on ILGM

Keep on growing!

Sources used for this article:

Avatar for Rob Sanchez

Rob Sanchez

Cannabis Cultivation Expert

Rob started cultivating in 2011 and worked in Colorado's medical days as a cultivator and hash maker before getting involved ... See profile

3 comments on “How to grow autoflowers outside”

  1. How much magnification is needed to clearly see artichokes ripening for harvest? Any particular tool preferred (jewellers loupe,magnifying glass,etc.)?

    • Hi Dale,

      Thanks for your message. A magnification of 60X is perfect for observing the trichomes! I’d recommend looking for any magnifiers made specifically for this purpose!

      I hope this helps, but let us know if you have any further questions!

      Happy growing,