marijuana pot size

Size of Pots for Cannabis Plants

Choosing a plant pot is an important but often overlooked task. They come in all shapes and sizes that are all going to effect the way your plant grows in some subtle way.

So what is ideal pot size for a cannabis plant?

It is best to keep your cannabis plants in pots varying between 1.5 – 3 gallons, 3 gallons being the norm (1 gallon is 3.8 liters). If you have a lot of room in your grow space then you may even want to consider 5 gallon pots.

What is the reasoning behind this? Well, cannabis plants grow long, winding roots; if they are restricted your roots can become “pot bound”. This simply means that there is not enough room for your roots; they cannot develop fully and thus will not be able to supply your cannabis plants the nutrients to the extent they require – leading to nutrient deficiencies.

3 gallon pots tend to be the most commonly used pots, these offer a good balance between pot size and room to grow – your cannabis roots should have adequate enough room for a decent grow, whilst the pot doesn’t take up too much room in your grow room, allowing you to grow more plants in a restricted space.

As previously mentioned, if you have enough room, you may want to consider 5 gallon pots (or even bigger). The draw back of them is that they take up a lot of room, so it can be fairly restrictive in smaller grow areas. However, if you have the space then it can help with the production of some big yields! (light, nutrient and other factors permitting). Having a 5 gallon pot allows enough room and freedom for your roots to grow to their full potential. Cannabis tends to do most of its root growth during the vegetative stage, by encouraging huge root growth early on in this phase you set yourself up for some potentially solid yields – by having an abundance of roots towards the flowering phase your plant can take up all of the water and food it could ever need, accelerating the amount it can grow. It should be noted, large pots are an enabler; they do not directly cause better yields, but have the potential to facilitate a situation where it can happen.

You will want to make sure that your pots are perforated (have holes in the bottom). These should rest on small dishes within your grow room. This allows for easier watering; it makes sure excess water can rest in the dish without flooding your pots – you can then remove this excess water from the dishes at will to ensure that your plants do not end up being over watered. You can also opt for putting your pots into large trays, this a more professional approach as you do not have to worry about each individual dish, but makes it harder to empty out excess water.

Make sure to thoroughly clean you pots before bringing them into your grow space, there may be chemical residue or other impurities left over from the shop or factory. It is also important to only put one plant in each pot, no matter what the pot size is. This will stop any need for competition between plants as well as make sure that any problems that may occur are isolated – should the soil in one pot accidentally build up toxic levels of nutrients, it will only affect one plant.

As you can see, the size of your plant pot can have a large impact on how your plants grow. It is most important to make sure your roots have enough room to develop and grow, otherwise you may find that you have a stunted plant. Giving your plant more room than it needs can let it really flourish. However, you must bear in mind, whilst having too little room will definitely negatively impact your plant, having loads of room is not going to get you extra results unless other, more important factors such as light and nutrients are at optimal levels.

Different pot sizes

The plants above are both autoflowering Flying Skunk’s (with all leaves trimmed) and have been grown under the exact same conditions. The one on the left is a 12L pot and on the right is a 4L pot. Notice the difference in size of the 2 plants.

Size of Pots for Cannabis Plants Choosing a plant pot is an important but often overlooked task. They come in all shapes and sizes that are all going to effect the way your plant grows in some


Choosing the type of pot is one of the first decisions we must face when starting our cultivation. To make this choice, we must look at the characteristics of our crop and our plant to choose the one that best suits our needs.

The type of pot directly affects the health of the root system, which in turn is decisive for the correct development of the plant. Healthy roots allow the plant to feed and hydrate properly.

Therefore, in this post we will describe the types of pots that exist and the different capacities that we can find of them so that your choice is much simpler.

Pots for cultivation

Pots for cannabis cultivation could be basically classified into two main groups: plastic and cloth pots.

Plastic pots are the ones that have traditionally been used in the cultivation of cannabis, there are different shapes and sizes, so we can choose the one that suits us best according to our priorities.

Fabric pots are relatively new and less frequent, but they have been well received due to their advantages: greater aeration of the substrate and root system and natural pruning of roots.

Before starting your pot cultivation, you will have to clarify what type you are going to use and, although it may seem a rather irrelevant subject, it is much more important than we can believe a priori and can be a determining factor when it comes to succeeding in growing because, a correct choice of the type of pot that we are going to use, directly affects the health of the plant as well as the efficient use of the space dedicated to the crop.


Black square pot:

Black square pot

Are the classic plastic pots available in different sizes. They are the most common and are made of rigid plastic, so they are easily washed for reuse.

The black pots are especially suitable for indoor or outdoor cultivation in cold months as it absorbs heat and during the summer months outdoors will damage the roots due to excessive temperature.

White square or round pot:

White square or round pot

White pots are specially designed for outdoor growing during the season and the hottest months because the white color reflects light and prevents the root system from getting too hot.

These pots can be found square or round, with and without handles. The shape of the flowerpot influences the structure that the plant will have when it grows, but we must take into account that in indoor crops, as a general rule, it is advisable to use square pots to make better use of the space.

White culture bag:

White culture bag

Of different sizes, the culture bags are a very convenient and practical alternative because they can be stacked, are very easy to transport and allow a quick and easy transplant, the bottom of the bag is cut and introduced in a larger size, which generates very little stress to the plant.

Once the culture is finished, we can clean the bag very easily or directly dispose of it. Recommended for both indoor, where we will take advantage of the space and outdoor.

Colored pots:

The colorful pots allow us to identify the variety of marijuana that we are cultivating without the need to place identifying labels, they are sold in packs of 90 units. These pots have a capacity of 0.30L so they are ideal for the germination phase and for cuttings.

Airport-punched pot:

Is a pot containing orifices so that the roots of the plants do not spiral and, in turn, when they protrude through the holes, the air will prune the roots naturally. This natural pruning causes the root system to develop permanently, which has a direct impact on the plants, accelerating their growth and giving them a denser and more compact structure. They are ideal to avoid that our plant acquires a too high bearing, as well as for mother plants.

Grid pot:

This type of pots is specifically indicated for hydroponic and aeroponic crops. The gratings in this pot allow the roots to leave without problems while keeping the clay balls inside. They are comfortable and economical and can be washed and reused again.

Raised pot:

It is the classic black plastic square flowerpot in which there is an elevation that allows greater aeration. It is easily washable and reusable.

Cloth pot:

Fabric pots can be found in both black and white, as well as in different sizes to suit the needs of the crop.

The great novelty of the cloth pots is that they are made of a material that allows the aeration of the substrate as well as performing a natural pruning of roots using a method similar to the one used in the aeropot pots. In addition, once the crop is finished, we can wash them and use them again.


  1. Small pots (between 0.5 and 2L): these pots are usually used for planting once the seeds are germinated or for rooting cuttings, so they will be the first pot of our plant’s life cycle.
  2. 3.5L pot: used for the growth phase indoors or directly after germination of the seeds outdoors. Once the root system has occupied the entire pot, one of greater capacity must be transplanted.
  3. 5.5L pot: used mainly for indoor crops and for the first stages of outdoor growth.
  4. 7L pot: one of the most common in indoor growing, where they are also used for flowering stage. It is also used to perform transplants from 3.5 pots in outdoor culture.
  5. 11L pot: this is the maximum size that we should use for indoor crops. It is used outdoors to perform transplants from 7L pot during the growth stage. It can also be used for growing autoflowering strains.
  6. Flowerpot of 18,19 or 20L: it is the ideal capacity for the culture of autoflowering plants since these should not be transplanted and its capacity leaves enough space for a correct development of the root system. They are also used outdoors for transplants from 11L pots.
  7. 40L pot: these pots/containers have a larger capacity and are intended for outdoor cultivation of the best strains. They are equipped with handles for easy transport.
  8. 50L pot: For those who are outgrown by the other pots, you can choose the 50L pot, made primarily for growing season varieties outdoors, where you will get plants of medium / high structure.

Other features

The pots must be the right size for your plants: if they are too small, the root system will not be able to develop and the plant will not grow properly and if they are too large and use more substrate than we need, which will increase the cost of cultivation, the root system of the plants tends to occupy the bottom and edges of the pot so it would leave a lot of space unused.

The roots tend to grow downward, sideways and deep, so most pots have an elongated rather than wide shape, which will guarantee a more extensive root system.

Remember that all the pots must have a drainage system to eliminate excess water. You can complement your pots with other accessories such as plates and trays to help collect the leftover water.

Always make sure you always choose the right products for the crop you are going to grow a correct decision helps to avoid future problems.

Finally, it is important to keep in mind that transplants can only be performed during the growth phase, NEVER during the flowering cycle.


santiago 13 September, 2019, 1:31 am

I have a micro=organism that I can not eliminate,Its a red dot on the trichome that devours the trichome and leaves no potency. I have been trying for 3 years to rid of it, I can not get any help. I do not know what it is. I see it ubder the microscope . but thats all . I tried everything possible . insecticides.miticides,hydro peroxide. nothing works. where can I gat help?

GeaSeeds 13 September, 2019, 8:03 am

We need more details to know but it looks like red spider.
We have a post that explain how to kill red spider.

Choosing the type of pot is one of the first decisions we must face when starting our cultivation. To make this choice, we must look at the characteristics