Best Pot Size for Cannabis Grow

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Added 01 September 2020

Pots come in a lot of shapes and sizes, but which ones should you use to grow? Read on for some top tips on the best pot sizes for your cannabis plants.

Best Pot Size For Cannabis Grow

Choosing the Right Pots

Choosing the right pot for your cannabis plants can be a little confusing when there is so much choice on the market. If you are a beginner you may be overwhelmed by all the different kinds of pots you can grow in. This guide is here to simplify the process for you so you can maximise yields with the best pots.

The first thing is, give it space! Pots with enough space for the roots are key to a successful grow. Your yields will be bigger if the roots are happy and healthy, so make sure they have more than enough room.

Bigger Pots, Bigger Yields

Making a decision on which pots to use can determine many things about the success of a grow. The best pot size depends on what results you are trying to achieve.

If you are looking for big yields, then large pots are recommended. When a plant is limited by a small pot it makes it harder for it to maintain its growth and will only end up producing lower yields.

Large Pots Are Best For Outdoor Growing

Roots grow very fast and do not like being pot bound. If roots cannot grow properly they begin to lock out nutrients and will stunt the growth of the plant. Remember, everything grows from the roots. The roots need space and if they are limited then they will not be able to fully develop, meaning your plant won't either.

Only do one plant per pot. You do not want plants fighting over nutrients or space.

Roots Can Eventually Become Pot Bound

Roots can eventually start to become pot bound.

6 things to consider:

  • How big is your grow space? Consider the size of your grow space and think how many plants you could fit there without them being overcrowded.
  • What is your budget? If you are on a tight budget, choosing massive pots may not be the best option.
  • What yield are you looking for? Bigger pots means bigger yields.
  • How many plants do you want to grow? Manage them correctly and lots of small pots can work really well in a small space.
  • How much work do you want to put in? Large pots require harder work, heavier lifting and more cleaning.
  • What strain are you growing? Plants that are tall or need to be grown outside usually need bigger pots than short and bushy strains grown indoors do.

Tip: One of the best ways to maximise space efficiency in your pots is to transplant. Starting a plant in a small pot allows root mass to build up without the roots having to spend too much energy finding nutrients or water in it's early stages.

The Best Pot Size

There are all kinds of pots in many different sizes. The average pot size for an indoor grow is around 2.5 gallons (10 litres). Don't go too much smaller than 2 gallons or your plant may not have enough root space to grow to it's full potential.

Pot Size Determines How Big Cannabis Plants Can Grow

The following guide will give you an idea of what pot sizes you might need in relation to the size of the plant you want to grow. Obviously this is just a general average and depends on everything we mentioned previously, but will give you a good starting point.

Pot size(Litres) Pot Size (Gallons) Approx. Plant size (in) Recommended Grow Space (m2)
7 2 12 0.75 x 0.75
15 3 24 1 x 1
25 5-6 36 2 x 2
50 10-11 48 3 x 3
>50 >12 60 >4 x 4

Ideally you want pots that are big enough for the plants to be fed or watered everyday. It is not a good idea to have a massive pot that you only water once a week because your plant won't get the regular dry/wet cycle it needs for proper oxygen or nutrient absorption.

Small pots can be used in the early stages of the growing process for easier management of plants. If you are germinating a lot of seeds, it can be a good idea to start them in small pots to transplant later on. Transplanting is a great method if you are using a vegging room for growing indoors or outdoors.

Small Pots Can Be Useful For Transplanting

Indoor and Outdoor Pot Sizes

Pot size makes a difference if you are growing indoor or outdoors. Normally outdoor growers have a lot more space so they choose big pots to grow massive plants. Indoors is slightly different and requires a bit more consideration when it comes to choosing the best pot size.

a. Indoor

Growing in a tent can get quite complicated when you are in a small space so before you set up imagine how you will need to move around the space once it's full of plants. You want to have easy access while still giving the plant enough space to do it's thing.

The standard pot size for an indoor cannabis plant is between 2 and 6 gallons (7-25 Litres). Anything bigger than this might end up being too difficult to manage inside. This all depends on your available space but you will need to reach the plant for things like watering, cleaning or moving.

Tip: You want to use pots that have plenty of drainage holes in the bottom. This is super important for good water and air flow, especially indoors. Placing a tray under your pots allows the excess water to collect at the base.

Proper Drainage and Aeration is Good for a Cannabis Plant

b. Outdoor

If you have a big outdoor space then you probably want to get bigger pots. As you know, bigger pots usually comes with bigger yields, so try growing outdoors if you have the possibility to.

Also consider how long your grow cycle will be. If you plant early in the spring you will probably need to use a bigger pot to support the growth of the plant throughout the year.

If you are not planting directly into the ground, it is recommended you use a pot between 10 - 12 gallons. There are increased costs of using larger pots as well, as you will have to fill them with growing medium. 

This is why outdoor plants grown directly in the ground can end up being so huge; because the roots have an infinite amount of growing medium to grow in! It is worth it to make the extra investment in bigger pots if you can afford it.

Outdoor Plants by ButtersStotch from Grow Diaries.


There are many factors that will determine what is the best pot to use so it is better to go slightly bigger if you are not sure. Your plants will be happy to have more than enough space to sustain their explosive growth throughout their life. Try some different pots and see the results for yourself. In the end only you can decide which pots are best for your setup and requirements.

If you have some comments on what you think is the best pot size we'd love to hear them so feel free to share your thoughts below. Let's grow together!

External References

Pot Size Matters. - Poorter, Hendrik. (2012)

This article was updated August 2020.


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With your logic, a plant grown in an endless pot (outdoors in a field) will grow to the moon. Yes pot size matters to a certain extent but once you get past 7 gallons or so you won't see a larger plant because the root span is limited. Plus the growth / size is dependent on strain. Most Indicas won't get very tall regardless of the pot size, most sativas will. You can't lump them all into a chart (even in a generalized sense) and say this size pot will yield this much growth. Pots 10 gallons and up are a complete waste for most strains, though I get it's easiest to say 'when in doubt go big.'
Superbe article bien aimer les infos Je cherche à savoir pour le substrat L avez vous ? Merci
good work but ..... the table is unfortunately wrong and does not agree with plant height diagram. 7 litres 12in / 60cm are not same. table needs to start at 3litres
Hey, Josh!) Great job, but not even a word about airpots. They deliver great rootballs and allow plants to grow bigger!
Also dont forget to clean your Tray, you dont want Swampweed!👽
This was very helpful 👊 @joshuaholt
Salut la communauté, merci à toi @JoshuaHolt pour cet article très complet et intéressant. Prenez soin de vous, peace..🌱