How to select the container size for Cannabis?

How to select the container size for Cannabis?


Selecting a container may seem like something not too important for your cannabis, but in reality, it certainly is! The type of the container, its size, and the material it is made of significantly affect how the plant will develop in the future.


There are containers of all sorts of sizes and shapes, as with everything you can find premium versions with some extra features that will facilitate growth. Whilst a basic plastic one just enough to do its job will cost a few bucks. Is there a truly substantial difference between those and how do the size and material matter? This article will help you to find out!




The first and foremost factor is of course the size of the pot itself. The reason why it is so important is that cannabis has extremely long roots, which means that a lack of capacity will limit the development of the root system. That subsequently will constrain the growth and potential maximum size of the plant. 


So the rule of thumb is the following  - go for the biggest container you can afford given your available room for it. Some extra soil will never have any negative effect, whilst the future yield won’t be limited by the capacity factor. 


Speaking about the minimum size I would recommend the following table that over years of growing proved to be reliable. It is based on the plant’s age and suggests the ideal amount of room for every age bracket.


0–1 week
Root cube
1–6 weeks
10cm pot
6–8 weeks
10 litre container
2–3 months
14 litre container
3–8 months
22 litre container
8–16 months
45 litre container


Note that for auto-flowering plants which tend to go through the full cycle in 3 months the minimum pot size will be 14 liters. 




Let me walk you through the different pot materials that are available on the market. The types that you can find in the grow stores are typically made from plastic, wood, metal, clay or plant fabric. They vary by cost and each type has its pros and cons, which have to be taken into consideration.


 For instance, clay pots drain moisture from the soil. Therefore you would need to water the plant in such a container more often. Metal containers can rust, cause overheating or even contaminate the plant. It’s actually the only material that I recommend not to use for cannabis. Wood containers on the other hand do not have such problems, but oftentimes are large and expensive. 


Cheap and cheerful plastic pot 


Plastic pots are certainly the most popular ones as they cover all the needs for a tiny price. They are clean, durable and cheap. Not the most good-looking but definitely get the job done! The only issue that I would point out is that plastic effectively retains heat. However, you can minimize this effect by selecting a pot of bright color. White will be the best one while black is a certain no-go, as it will facilitate the light heat absorption.

Fabric pot   


The type that is worth having a close look into is a fabric pot, often called a “smart pot”. Those containers are made of horticultural fabric and have some extra features. The porous fabric traps the roots when they reach the pot's sides, and the air outside automatically prunes them. In fact, this "air-pruning" encourages root development and keeps plants from becoming root-bound (ie. outgrowing their pots). Due to their porous construction, fabric pots also have the benefit of making it nearly impossible to overwater your plants. As excess water will always find its way out of the pot.


However, as a side effect of this, you would need to water your container more frequently, as moisture quickly evaporates through the porous pot walls. Quite a great trade-off for boosting the root system if you ask me.


Classic clay pot


Finally, classic clay pots that you certainly have seen at your mother’s house are a decent choice as well. They look great aesthetically and give that winter garden vibe, which makes your growing corner cozier. Keep in mind that those require an extra piece - a matching saucer that catches the water that runs off below the pot.


Besides, It's crucial to know that these pots require drainage holes at the bottom to prevent water logging. Not every pot has holes; frequently, you must drill them yourself before growing your plants. Buy clay pots with preset holes to avoid extra hassle. Moreover, a clay pot is exceptionally decent for robust plants, as it provides some extra support and stability with its heavy weight. 


Lastly, it has a natural ability to soak and store the excess water, which provides a cooling effect that is exceptionally beneficial for the root system during heat wave days.


I hope that this article helped you to get a better understanding of what is important when choosing the container. As well as which type will be the best considering your budget and growing environment.

Back to blog