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!