When buying a pot (growing container) for your autoflowering cannabis grow you need to know how small or big of a pot to get. And that can be a bit tricky.

There are many opinions out there regarding how big or small should the pot for your autoflowers be.

But the truth is that no two plants are exactly the same and before choosing the right pot size you need to think about all the aspects that will affect your decision.

How to determine the best pot size for your autoflowers?

Regular cannabis strains have a great rule for determining the pot size – you should get a gallon (3,7 liters) of growing medium volume for each month that the plant will be alive. Or you can just anticipate how big your plant will become and get a gallon for each foot (30,4 cm) of growth.

So, if your plant will grow for 5 months you need a 5-gallon (18,5-liter) pot.

However, it’s not as easy to choose the best pot size for autoflowering plants because you need to think not only about how long will your plant live but you need to also think about the size of the plant and how big you want it to get.

Most people choose autoflowering strains because their growing space is limited and they can’t grow plants that stretch to 1 or 2 meters (3,2 or 6,5 feet) in height and pot size can greatly affect the plant’s height.

If you plant your autoflower cannabis seed in a small container like a “Dixie cup” then it will stay short because it will become pot bound (root bound) fast and that will stress the plant slowing down its growth.

Usually, autoflowering marijuana plants don’t grow more than 18 inches (45 cm) in height and they usually are ready to harvest in less than two months. If we know these numbers then we can calculate that the best pot size for autoflower plants is 1,5 to 2,5 gallons (5,6 to 9,4 liters).

Any experienced grower will tell you that if you want your autos to reach maximum potential then you shouldn’t get a pot that can hold less than 1 gallon (3,7 liters). While getting a pot that is more than 3 gallons (11,3 liters) will be a waste of money and soil because the plant can’t grow enough root mass in two months to fill a 12-liter pot.

This means that the answer to the age-old question of what size pot should I use for my autoflowers is a 1-gallon, 2-gallon, or 3-gallon pot.

But if you want to maximize the yield of your plants and don’t want to waste any growing space or dirt, try different pot sizes and see how the particular autoflower strain you’re using grows in different sized pots and determine what is the perfect pot size for it!

Why does pot size for autoflowers matter?

For the small and micro-scale growers, pot sizes can also be a big advantage because you can easily manage your plant’s size by potting it in a smaller container!

This small container will soon be full of roots and that plant will be root-bound and won’t grow as fast as it could but it will stay small. And for small spaces, small plants are perfect!

This small plant can be further trained with the low-stress training (LST) method and with small pots and training growers can get a very good yield in small spaces!

Basically, a smaller pot means a smaller plant so you need to experiment with what pot sizes are good for your autoflower grow and stick to that one size because transplanting autoflowers will decrease their yields therefore it is best to start them in the container that they will be grown in!

My experience with different autoflower pot sizes

I, myself, have grown autoflowers in 4-inch (10.16 cm) pots, 1-gallon (3.7 l), and 3-gallon (11.3 l) pots, and the 3-gallon pots did the best!

For my first cabinet grow I used smaller 4-inch pots because I needed the plants to stay small but I got only a few grams from each of them.

The 1-gallon pots already gave me much bigger plants, while the plants in the 3-gallon pots were the best.

With those 3-gallon pots I had over 70 cm of vertical growth with a lot of side branches and from that point on I usually use the 3-gallon ones!

Now that you have figured out which is the best pot size for autoflowers, learn about other things that affect the autoflowering cannabis plant size and yield.


    • That is true, but you cant get big yields from small pots, so for every grower and every situation a different pot size is needed!

      • my game is – put them in the largest pots available so they can grow the largest.
        Nute em regularly.

          • But I heard that pots too big for your plant will produce non-dense buds?

      • Moondude on

        Hello Midowo, Your writing and knowledge has been a blessing to me. I have been through many reputable sights and have landed here.

        I am curious to know if this pot size post (max 3 gal) is valid with the increased productivity of Super Autos?

        While I have your attention, I bought Foxfarm Ocean Forest, I believe this was a mistake. I fear it may be too hot for Autos? With this product would it be best to cut 20% with coco, or get a new bag of soil?

        • Hi Moondude,
          Tnx for the great words!
          The post was intended for regular autos and you are completely right that for super autos you would need a larger pot size but in general I think that most super-auto strains will do just fine in 3 gallon containers.

          About the soil – that depends on the strain that you have. Some stronger strains from sweet seeds and some of the original autos grow great in Foxfarm Ocen Forest but some of the newest breeds can get a bit burned. If I were you I would do a thorough research about your particular strain and then see if I need to add that coco to dilute that soil or not.

        • best to mix ocean, with light warrior. 1.5 ft2 ocean, 1 ft2 light warrior . then mix in amendments, perlite or others, i will use rice hulls PBH for less chemical addition. Going to mix fox farms soil and mix. then add 30% rice hulls.

  1. terry 208 on

    Oh man i’m a 1st time grower and I planted a auto.bubblicious seed in a 5 gal cloth pot, at 5 wks. it’s3 1/2 ft. with over 40 branch’s I had to remove the closet shelf to raise the light (250w cfl grow light) it’s very strong and healthy with a thick main stalk and covered with pre-flowers and bud nodes it’s just to big! next grow i’ll use a 2 gal. pot

    • Hi there terry!
      It sounds amazing 😀
      Yeah pot size iz an awesome way to control height!
      Have you tried LST?
      What nutes are u using?

      • terry 208 on

        Hey Midowo, I read your article on LST I,m going to use it on my next grow I think it may be to late for this monster.i,m using Beastie Bloomz 0-50-30 from Foxfarm and diluted urine (1oz in a 1/2 gal. of water) thanks for all the incredible info, you are truly a cannabis god!

        • tnx 😀
          I think it is never too late to LST but in this stage you need to be careful as the plant is not as resilient and can bend or break.
          But yeah, if you can manage without LST then go with it!
          good luck, and if you have any questions don’t hesitate and ask!

    • I have heard about those air-pots do they really work magic on your plants? I have heard many growers saying that they wont trade those pots for anything else after once trying them.

  2. haze head on

    hello all I have a dark devil auto in an 33 litre pot the tallest side branch is 80cm its been growing for 7 weeks omg its big:) I have pix bbut cant post them will my plant still take the same amount of time as if it was in a 11liter pot?

    • If the genetics of that strain are stable then it should grow for the same amount of time in any pot , but I have seed that in larger ports autoflwoers will take a bit longer to finish! How far is the flowering?

  3. Hello great blog and conversation in the comments. Just what soil would you recommend for an auto indoor as well as which nutes?

    Also an outdoor auto any tips to know

    • I have an 2 months auto northern lights on a 21L smart pot and the roots are starting to come out from the bottom, what should I do?

  4. llllll|llllll|llllll on

    Trying to figure out pot sizes is often quite a headache. You’ve got some in inches, some in gallons, and even some in fluid ounces; There’s a theory going around that this purposely confusing system is a way for the mass market industry to charge more for plants, by container size, not necessarily Plant Size!

    Here’s a break down of various sizes and measurements and set some general “accepted standards” for pot sizes.

    4″ pot= pint (0.5 quart)
    5-6″ pot = quart (0.25 gallon)
    7-8″ pot= 1 gallon
    8.5″ pot = 2 gallon
    10″ pot = 3 gallon
    12″ pot = 5 gallon

    *Please remember these are rough estimates and not a science.
    10″ pot = 3 gallon
    12″ pot = 5 gallon

    • Many factors go in this equation for growing. For myself, it begins with the seeds, the strain, etc…… the pot I’ve been using for my indoor autos has remained the 2 gallon, black, fabric, pot. I’ve used this for a few years now and it’s always been a nice grow medium ( I use , either Ocean Forest & Soil, or Coco Coir & Soil). My autos are usually between 2 and 3 feet, growing between 15 grams (not so good) to 4 ounces (Extremely rare for me)! Point is, there is not an exact science (YET) for what you can get outta autos. I guess that is part of the enjoyment in growing , “like a box of chocolates, you never know what your gonna get!” Happy growing, my brothers and sisters, and have a beautiful week! Much love.❤️????????????????????????????

  5. I got a question, I’m growing a plant in a 7in. Pot and 8in. In diameter, my plant is 4in. Tall,and has about 10 branches and is 4 weeks old, how long before I have to transplant.?

    • That depends on your grow room conditions. I would probably start my plant in something bigger from the start but if you want to transplant do it as soon as possible to let your plant recover more easily.

  6. diskokobaja on

    Im using 18l pots dor my autos? this is my first grow,so i have 6 plants in1m2 and its overcrowded..so you are telling me tobuy 12lpots?

    • 18l pots could be an overkill but if you have a strain that grows big then 12l pots could be too small. That all depends on the strain you are growing..

  7. cantwait on

    ive got a couple inside and outside grows under my belt but am trying autos for the first time.my grow area is my garden tub, ive got 2 dp polar lights #3 in 25L pots under 8 lamp 4 foot t5 . I live in Colorado so its a legal grow behind locked doors , any advice ?

    • Hello,
      If you have already grown regular photo-sensitive strains then autoflower growing will be even easier. The main differences with autoflwoers is the light schedule (either 24/0 or 18/6 ) and that they need less nutrients than regular cannabis strains. DP Polar Lights #3 looks like a very great strain and it should have pleanty of room in those 25L pots.

  8. Black kushh on

    Hi there. Very useful. I plan to grow auto for commercial grow. And have q about autos. First I have a 40lit pot. How is it? Is it waste of time and dirt? And another thing. I read somewhere that until the 5 or 6 weeks plant is in veg and should be nut with veg nut and at6 week should start bloom nut is it true? I plant to buy six shooter fem seed and maybe some green crack for its yield and high level of THC
    Thanks again

    • Hi Black kushh,

      I think 40 liters are a bit too much for even a super autoflower strain.

      Abut nutrients it is best to give autos VEG nutes till they start showing pre-flowers and then slowly change the nutrient mix to a Flowering one. but ebcause every strain grows differently you can’t just make a schedule where you change those nutes in week 6.

      Good luck!

  9. Hi all
    Frist grow,
    Will having bigger pots effect the hield with autoflowering ?
    I’m using 18l air rocket pots.

    • Ji James,

      Yes, bigger pots = bigger plants, but up to a point, because if you get too big containers you will jsut be wasting soil.

  10. nachovte on

    Thanks for the info!! Its ok to plant on a balcony in 7L pots? Or the info applies only on interior growrooms? It will be plenty of sun and a nice template weather. Good mix soil. Nutritents.etc. Thank u!!

  11. Hi everyone,
    Just about to start my first grow, i have a secret jardin dr90 (approx 1m sq) I have 7 white widow autos from pyramid seeds and 1 auto purple from the same people, I plan doing 4 widows and the purple, I have 10ltr pots, my light is a 400w dual spectrum hps, I have all the necessary extraction etc. I have a few questions if anyone would be so kind to give me some help…
    Are the pots big enough?
    Will my lights be ok from seed to harvest?
    I have coco, perlite, and Levington multi purpose compost rich dark blend with added seaweed and it says it feeds for up to 8 weeks, does that mean I don’t need to add anything for up to 8 weeks?
    What ratios should my soil mix be?
    I was planning feeding just water for the first 2/3 weeks then start adding nutes, is that correct?
    As for the nutrients I was just going to use a “normal” fertiliser that contains potassium, nitrogen etc (think it’s a basic one really, I also have these small drip feed fertilisers that you just stick in the soil and it slowly feeds it (I assume) are they ok to use?
    Pretty much all the questions anyone would need I suppose, I have read a lot but there seems to be lots of different answers so if anyone can help that would be great, again I am a complete novice so please excuse if any of my questions seem stupid!

  12. Would it not be a good ideas to grow 2 plants in a 5 gallon bucket would the roots interfere with each other?

  13. Dmannnnnn on

    What’s is the light schedule for autoflower from seed to veg to flower. Indoor grow

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