How and When to Transplant Cannabis Seedlings

If you want your marijuana plants to thrive, transplanting them is essential. It is the process of rehousing the plants from one container to another and is a critical step in their growth cycle that could impact their health and yield.

However, rather than focusing on transferring mature plants, this article will instead outline how and when to transplant cannabis seedlings. This is a crucial guide whether you’re moving seedlings from a germination tray to individual pots indoors or else you’re getting them ready for outdoor planting.

What Is Transplanting Cannabis?

Transplanting cannabis is the practice of relocating a marijuana plant to a bigger container or new substrate. The goal is to increase and improve root growth.

A marijuana plant’s roots require oxygen, humidity, and darkness. They dislike direct light, continuous air and oxygen, so these are factors you must consider during the transplanting process.


Like most growers, you have no idea what percentage of cannabis seeds will sprout, germinate, or be female (if you didn’t purchase feminized seeds.) As a result, you plant as many seeds as possible in small pots to increase the likelihood of having a decent number of usable plants.

At some point, transplanting cannabis becomes necessary to ensure the plant’s root system spreads out. During the seedling stage, the plant’s main goal is to ensure the root zone is properly developed. If the seedlings struggle at this early stage, they might not survive in the long term. So, you need to transplant your cannabis to give them the best possible chance of survival.

The Importance of Transplanting Marijuana Plants

Transplanting ensures the plant’s roots have the opportunity to spread out. Consequently, it is more likely to grow and flourish. Placing the seedlings in a fairly small container is another crucial consideration since it’s easy for them to get the optimal mixture of water and air. By contrast, placing the seedlings in a large container could cause them to become waterlogged.

The last thing you want is for your plants to become rootbound. This is the term used to describe when the roots become tangled and basically choke the plant. This can happen when the roots have taken up all the available space in the pot. At this point, they begin to run in circles inside the container.

There’s a serious danger of the plant dying in this scenario. Even if this isn’t the case, your plants won’t reach their full potential. Signs of rootbound plants include nutrient deficiency, stem discoloration, and stunted flower production.

When to Transplant Cannabis Seedlings?

Typically, you’ll need to transplant your marijuana plants at least once, if not twice or three times, during their life cycle. For instance, you may swap from a 1-gallon to a 2-gallon pot around four weeks after the seed germinates. Then, once the plant is a couple of weeks away from the flowering stage, you can transplant it into a 5-gallon pot.

However, there is no set-in-stone time to transplant because it depends on the plant’s speed of growth and size. Also, you may have problems with watering or general growing problems that serve as indicators that a transplant is required. Here are some things to look out for when determining the right time to transplant your seedlings:

  • When you can clearly see that the plant has outgrown its starter pot
  • If you find that the plant’s growth has accelerated (transplanting quickly in this situation is imperative lest the plant’s growth becomes stunted)
  • If you can see roots coming out of the pot
  • If the pot’s soil is drying out quickly
  • Whenever you see that the plants are looking sickly (check whether a transplant is necessary as the pot size could be the reason)
  • If the plant has sprouted several sets of leaves

Incidentally, if you move from a starter pot to a slightly larger one, a second transplant near the end of the vegetative stage is necessary.

Size Matters: Here’s How Much Space Your Marijuana Plants Need

As a general rule of thumb, ensure the pot you’re moving the plant into is at least twice the size of the previous one. Otherwise, you’ll have to complete the process on multiple occasions, significantly increasing the chances of transplant shock.

Some growers begin with 16-ounce containers and move to 1-gallon pots once the plants are 6+ inches tall. By the time your plants are more than 12 inches tall, a 3-gallon container becomes a necessity. Switch to a 5-gallon container when the plant exceeds the 24-inch mark.

Typically, there’s no need to go beyond this container size if you’re cultivating marijuana indoors and aim to keep the plant’s size under control. However, if your plants go beyond 40-42 inches, you may need to transplant them to a 10-gallon pot. Still, this is mainly a requirement for plants cultivated outdoors.

If you’re not completely sure what the pot size should be, ensure it is slightly larger than what is required. Yet, you must be careful not to go too big, too soon.

Why Don’t I Use the Biggest Container Right Away?

There are doubtless some readers wondering why they can’t place their seedlings directly in a 5-gallon pot from the outset. After all, this would eliminate the need for transplanting altogether.

Alas, this shortcut carries a major risk of waterlogging. If you place your plant in a large pot at the beginning, the roots won’t stretch out nearly enough. They also won’t soak up the requisite amount of water. As a result, when you water your plants, the liquid will remain in the pot for too long, leading to waterlogging and root rot.

If you insist on ignoring our advice and using a big container immediately, at least be careful when watering the plants. Give them just enough water during the first week or two after you’ve potted them.

Picking the Right Pots

There’s no need to overthink things when selecting transplant pots. You’ll get by just fine with run-of-the-mill plastic pots that have holes at the bottom. However, you should choose white pots to ensure the soil remains at a comfortable temperature. If you pick black or other dark colors, there’s a risk of the soil becoming too hot during sunny days as the pot will generate heat.

As far as seedlings are concerned, plastic solo cups are a solid choice. You may also find some pots specifically designed for seedlings if you check online.

Here’s How to Transplant Marijuana Plants

If you’ve read the article to this point, you’ll know that there’s a risk of cannabis transplant shock to consider. This “shock” stresses out your plants and hinders growth. Take your time when transplanting the plants and ensure you exercise good hygiene practices.


Avoid completing the transplanting process during sunny days or when your grow lights are shining intensely on the plants, as these situations can also shock the plants.

Transplanting Seedlings

First and foremost, please ensure you water the seedlings a day or two before transplanting them. It’s best if the soil is moist rather than wet. Use a 1-gallon pot for young cannabis plants and fill the container with high-quality soil before moving the seedlings. Water the soil and create a hole in the middle of the pot that’s big enough for the impending arrival.

Using gloves (you can use your hands, but wash them thoroughly first), cover the soil in the plant’s current container with your hand and turn it over. Take out the root ball carefully, and remove the old pot.

Once the plant is free, place your hand beneath the root ball and take the plant to its new home. Using additional soil, fill the gaps and pat the soil to ensure the plant is lodged in place. At this point, it’s a good idea to water the new plant a little and use a root stimulator if you have one.

For the next few days, keep a close eye on your seedlings. Look for stress signs, which may include yellowing or wilting leaves. If you see any problems, adjust the environmental conditions as needed. Also, take care to introduce nutrients gradually rather than risk overfeeding the plants.

What to Do During Future Transplants

Realistically, the above won’t be the only time you need to move your plants. Transplanting weed a second and third time is likely, but it doesn’t need to be a stressful situation.

Indeed, you only have to copy the steps outlined for the first transplant, always making sure that the plant’s new home is at least double the size of its old one. Eventually, if growing marijuana indoors, your plants will require a 5+ gallon pot. The final transplant should occur at least a week before the end of the plant’s vegetative stage. Avoid moving plants once they are flowering.

Final Thoughts on Transplanting Cannabis Seedlings

Transplanting marijuana seedlings is a delicate process. It requires a great deal of attention to detail and a gentle touch. However, as long as you follow the tips above and are patient, you can complete the process quite easily. Get it right, and you give your marijuana plants the best chance to thrive in their new environment.

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