When buying a pot (growing container) for your autoflowering cannabis grow you need to know how small or big to get it and that can be a bit tricky. There are many opinions out there of how big or small should the pot 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 some aspects that can affects your decision.

Regular cannabis strains have a great rules determining the pot size and they are – you should get a gallon (3,7 liters) of growing medium volume for each month that the plant will be alive or you could 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 5 months you need a 5 gallon (18,5 liter) pot.

With auto flowering plants it’s not that easy to chose the pot size because you need to think not only about the time 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 auto-flowering strains because their growing space is limited and they can’t grow plants that stretch 1 or 2 meters (3,2 or 6,5 feet)  in height and pot size can greatly affect the plants 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 the growth.

Usually autoflower marijuana plants don’t grow more than 18 inches (45cm) 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 perfect pot size for auto flower plants should be 1,5 to 2,5 gallons (5,6 to 9,4 liters). These numbers that we came up with are in fact very accurate and any experienced grower will tell you that if you want your auto-flower plant to reach maximum potential then you shouldn’t get a pot that can hold less than 1 gallon (3,7 liters) and getting a pot more than 3 gallons(11,3 liters) will be a waste of money and soil because the plant can’t grow so much root mass in two months to fill a 12 liter pot.

The perfect pot size is somewhere between these numbers and every grower that wants to maximize the yield and doesn’t want to waste any growing space or dirt must try different pot sizes and see how the particular autoflower strain grows in different sized pots and determine what is the perfect pot size for it!

For the small and micro scale growers pot sizes can also be a big advantage because you can easily manage your plants 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 wont 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 Low Stress Training and with small pots and training growers can get very good yield in small spaces!

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

I, myself, have grow autoflowers in 4 inch (10.16 cm) pots, 1 gallon (3.7 l) and 3 gallon (11.3 l) pot and in fact 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 and I got only few grams from each of them but the next time the 1 gallon ones were much bigger and the 3 gallon pots were the best. With those 3 gallon pots I had over 70 cm of vertical growth with lot of side branches and from that point on I usually use the 3 gallon ones!

Share.

20 Comments

    • midowo

      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.

  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

    • midowo

      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!

        • midowo

          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!

    • midowo

      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?

    • midowo

      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

  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

  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.?

    • midowo

      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?

    • midowo

      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..

Leave A Reply