In this guide we will teach you all about growing cannabis in containers. There are many different things to consider to grow top quality cannabis using pots. There is somewhat more work to grow cannabis in containers than in the ground outdoors.
Can you Grow Cannabis in Containers?
Cannabis grows very well in containers, providing they are the correct size and have a good cannabis growing medium with correct PH ranges. Growing in pots is very common for indoor growers, if not the most common way to grow cannabis indoors for hobby growers. Cannabis can grow in pots from start to finish with few issues.
Types of Containers Pros and Cons of each type
Not all growing cannabis containers are made equal, some of them will work better then others for growing cannabis. We will discuss each one’s pros and cons below and why we would recommend them over other types of cannabis containers.
Plastic Cannabis Containers
Regular plastic containers are the most common types of containers that growers use for cannabis cultivation. They come in all different shapes and sizes for the grower to use. They also come in many different colors. They work well for growing cannabis indoors and outdoors. One thing to watch for if using plastic pots, will be the color black. If you are using black pots they are more likely to absorb sunshine, and they can get very hot at times.
Also plastic pots are susceptible to having the medium pull away from the side of the pots. When this happens the water tends to run down the sides of the containers instead of the roots where the water is needed most. This can also cause dry spots in the pots as well.
Fabric Cannabis Containers
Fabric containers also work very well for growing cannabis and we like them over plastic cannabis growing pots. These containers are typically made out of a felt-like fabric in the shape of a pot. They have great air exchange for the roots, heat can easily escape the fabric on the sides keeping the root temperature from getting too hot.
A couple of negatives growing in fabric pots are that they can dry out much faster than plastic due to the amazing air exchange, this can dry out the pot much faster however. As they are made out of Fabric they are also not as sturdy as plastic containers for cannabis. Once they are full and the plant is in them, they are much harder to move around if needed indoors or out.
These containers come in all shapes and sizes, also you can get many different colors if needed.
Smart Pots are relatively new in the world of growing cannabis only around for the last number of years. We highly recommend these containers for growing cannabis. These containers offer the best of both worlds of the two previous types of containers.
They are made of hard plastic, covered in holes that direct the roots to each whole. The holes are located on the bottom of the pots, sides of the pots. The roots grow out of all these holes and this is very beneficial for the plant’s root systems.
They only have a couple of negatives, that the water will tend to run out the sides of the pots as there are holes at the top and bottom. As a grower it is harder in these pots to make sure the water is reaching all the way down to the bottom before it comes out the sides.
What is Air Pruning Cannabis Roots?
When a cannabis plant is air pruned it means that the roots have grown outside the pots and can no longer grow any farther. Essentially the roots have run out of growing medium to grow in. The roots will hit the air and “air prune” themselves at the edge of the growing container.
Air pruning works much like pruning the plant above the medium. When a cannabis branch has been trimmed, it will grow out two new branches from the nodes below it. This will make the plant busier with more growing tips on the plant.
The same can be said for air pruning cannabis roots. Once the root hits the edge of the container it will be pruned. Once this happens the roots will also grow new shoots from the air pruned cannabis root. The advantage to this is that every root tip can absorb oxygen and nutrients in the growing medium. So, the more root tips the plant has the more it can take up keeping your plants strong and healthy.
How Smart Pots, Fabric Pots Prevent Rootbound
One of the most important advantages these pots have over plastic pots, is they can prevent cannabis plants from becoming rootbound. This happens when the cannabis roots hit the sides of plastic containers.
These roots instead of air pruning themselves will turn the corner and circle the pots over and over until they are rootbound. When this happens it creates few important rooting tips in the container. The plant can start to suffer once the plant is very rootbound.
Can Cannabis Plants get root Bound in air pots?
So, because the cannabis roots that are growing in air pots, never hit the sides of the pot and “turn the corner” in the pot they will never keep growing roots in circles around the bottom of the containers. Air pots are for preventing and keeping cannabis roots from getting rootbound and affecting the health of your plants.
How important is the Container Size?
The size of the cannabis container is important in some cases, in other cases it is not so important. It is important that plants have the correct size of container for each of their growing stages. There is no point in having a 20 gallon pot for a seedling cannabis plant. Growers will want to have pots that fit the size of the plant they are currently growing in.
When starting out, germinating cannabis plants from seed, having a smaller pot is very beneficial for a smaller plant. However once the plant gets to a certain point in growth depending on the container it is growing in, the plant will need to be moved to a larger pot.
This is where air pots can come in handy, as they never allow the roots to circle around the bottom of the container, becoming root bound. With these types of containers you can grow extremely large plants in a very small container provided they have added nutrients as the marijuana plant grows.
When growing in normal plastic containers, growers will want to upsize their pots as the plant grows larger. This will provide more root for the roots in the container to expand rather than circle the container, causing the plant to become sick and eventually die.
Picking the Right Containers for Growing Cannabis
Growers can be successful growing cannabis in containers no matter the type they use. We have seen countless growers be successful, growing cannabis in used ice cream containers. Beautiful cannabis plants can be grown in beer cups to great success.
This being said, it is still important for growers, and particularly new or beginner growers to choose the correct containers for cannabis cultivation. When growing cannabis in containers, picking the wrong ones can mean death for your plants.
How to Choose a Container size during different Cannabis Growth Periods
Here is a list of cannabis growing containers sizes for Cannabis:
- Seedling Stages of growth – Small Container less than one gallon
- Three Sets of True Cannabis Leaves – 2 Gallon Container
- 7 Sets of True Cannabis Leaves – 5 Gallon Container
- 10 or More Sets of True Cannabis Leaves – 10 Gallon Container
Transplanting from Container Up Sizes
As your cannabis plants grow from seedling stages to flowering stages of growth it is important to transplant your plants into larger containers to give the root a place to expand and grow larger. Transplanting your cannabis plants will also help to prevent the plant getting rootbound.
If the plant is getting larger and looks like it is getting unhealthy, gently remove the plant from its container and check the roots of the plant. Are they starting to circle the bottom of your container, are they overlapping other roots as they go around the bottom of the pots? If so this is a sign that it is time to transplant the plant into a larger container. In fact if the plant’s roots have started to look like this, it is best to transplant even before the roots start to circle the container.
Do Bigger Pots Mean Bigger Buds?
While bigger pots can make it easier for growers to grow bigger buds, it is not necessarily true that you need bigger pots for bigger buds. You can grow very large cannabis buds in small containers, and larger buds have more to do with genetics of the plant rather than container sizes. If you are interested in looking at how large buds you can grow in small containers you can check out the “Solo Cup Challenge”. This is where cannabis growers grow the largest buds they can in small solo cups.
How to Keep Your Cannabis Containers Soil Cool in the Summer Heat?
There are a couple neat ways to do this in the summer when your roots in the containers are getting very hot in the mid summer sun.
Growers can use mulch to cover the tops of their containers. There are many types of mulch that growers can use over the soil in their outdoor pots. Adding some cut lawn grass around the tops of the containers will help them to keep water in, and the heat out. When adding mulch to the containers it acts like a kind of insulation for your outdoor pots. Keeping the soil cool in the hot sun.
Moving the Containers to a Shaded Area
If your containers, plants are not too large you can pick them up and move them to a shaded area in your yard on hot summer days to keep the containers cool. Once they are moved out of the heat they will start to cool down, keeping your roots cooler in the summer.
Importance of Great Drainage for your Containers
One very important topic we have yet to address in this article is container drainage. Having excellent drainage in any container is a must. This can be holes in the bottom of your pots, sides or anywhere else that will allow for the excess water to be removed from the growing containers.
It is never a good idea to have sitting water at the bottom of your containers for any reason. This can cause all sorts of health issues with your plants. Water can breed bacteria and fungus that will rot the roots of your cannabis plants. Once this starts it is very hard to stop as the root rot moves up though the container killing all the roots of your plants.
If your container doesn’t have any, or adequate drainage make sure that you make some by drilling holes on the pot’s bottom. Make sure there are many of them so there is never any water left. Water sitting on the bottom of the pots or the drain pans should never sit for longer than 30 seconds to one minute. If it does then the water will need to be drained off. You can read more about how to water cannabis plants here.
Why Risers are so Important with Fabric Containers
When fabric growing containers are sitting directly on the floor, this can breed mold. The bottom of the fabric containers are unable to have good oxygen exchange. The mix of water, lack of air movement/exchange creates a perfect mix that will breed mold around the fabric and grow in the fabric containers. The spores will spread, and possibly get into your buds, causing bud rot. You can read more about bud rot here.
If you are using fabric containers, it is best to use something called a riser, this will have a mesh bottom and your fabric pots can sit directly on top of it. Risers will boost the containers an inch or two off the floor, allowing for good air exchange under the growing cannabis in containers.
Why Healthy Roots are so Important Growing Cannabis in Containers
Keeping your roots contained in your growing container is very important to growing healthy cannabis and large flowers. When transplanting or checking your cannabis roots it is important to check that the roots are white in color, have no odors that smell like rot. Your roots should never be circling the bottom of the container.