Transplanting cannabis is an essential skill that every grower should master. Knowing how to repot marijuana plants can help you boost yield, keep roots healthy, and prevent nutrient deficiencies in the garden. To get you started, we’ll provide a detailed look at when, why, and how to transplant cannabis plants.
What Is Transplanting?
Transplanting is essentially “re-homing” your cannabis plant. This is accomplished by taking a plant from its pot and placing it into a larger container with more soil. Growers normally start their seedlings in small pots and transplant them as they grow larger. Some growers will repot their plants multiple times as they transition through the seeding, vegetative, and flowering periods.
Why Is Transplanting Cannabis Plants Necessary?
As cannabis plants grow, their roots expand outward in search of more water and nutrients. Once the roots have reached the edge of the container, they will start to coil around themselves, searching for any available space.
If left in a small pot, a cannabis plant’s roots will eventually run out of space and become root bound. When this happens, the root zone will become starved of oxygen, water, and nutrients. This can lead to a host of problems, including dying roots, weak and stretched growth, nutrient deficiencies, diminished yield, and the eventual death of the plant.
Transplanting isn’t absolutely required, as you can simply germinate a seed within a large pot; however, repotting can save you lots of time, money, and trouble in the garden.
The main reason growers start their seedlings in small containers is that it makes watering cannabis plants simple. Because seedlings have small root zones, they cannot take in as much water as mature plants. Therefore, the roots can quickly become starved of oxygen if exposed to too much moisture. It is very easy to overwater your plant when growing in an oversized container, as the pot will retain more water than the plant can use.
Another benefit of transplanting is that it reduces fertilizer expenses. If you start your plants in a large container, the nutrients will be flushed from the medium each time you water. Therefore, you must top-dress the soil regularly to feed the plants. On the other hand, if you repot your plants throughout the growth cycle, you’ll give them only as many nutrients as they require.
How Often Should I Transplant?
Transplanting offers many advantages but can also put plants through a lot of stress. The roots can become damaged if they are exposed to light, allowed to dry out, or handled roughly. Therefore, it’s best to repot your plants only when they have outgrown their containers.
Most growers repot their photoperiod plants two to three times throughout the growing cycle. Those growing autoflowering plants should avoid repotting altogether or minimize it as much as possible. If the plants become stunted, they won’t have time to recover before they begin budding.
When To Transplant Marijuana Plants
Knowing when to transplant will help to minimize plant stress while preventing problems before they arise. It’s important to repot your plants at the right time because it may take them a long time to recover once they show signs of being root bound. The general rule of thumb is to provide cannabis plants with five gallons of container space for every 12 inches of plant growth.
Growers typically place seedlings into small starter pots for the first two to three weeks of growth. Once the plants have entered the vegetative period, they transplant them into one-gallon pots. Right before flowering, they repot the plants into their final containers: usually three-, five-, or seven-gallon pots. If you are growing cannabis outdoors, you may want to transplant it into much larger pots or raised-bed containers to maximize yield.
As plants enter the flowering period, root growth slows as they focus on producing buds. Therefore, repotting is typically necessary only during the vegetative period. It’s a good idea to avoid transplanting flowering plants altogether, as it may stunt their growth, thus lowering their yield.
It’s important to note that different cultivars have different requirements regarding container size. For example, Bubba Kush is a short, stocky strain that looks small above ground but quickly develops an extensive root system. It may seem like the plant doesn’t need to be repotted when, in reality, it has already outgrown its container. Therefore, you’ll need to learn to read your plants to determine when they are due for transplanting.
Signs That You Need to Transplant
Cannabis plants often give us clues that they are running out of root space. It’s vital to be able to identify these signs and symptoms before your plants become stunted. Some indicators that your plants need to be transplanted include:
- Frequent Waterings: A good potting soil is able to retain a little moisture to keep the plants hydrated. However, if the roots have outgrown the container, there won’t be enough soil left to retain any water. If you notice that the medium is drying out much faster than before, it might be time to repot your plants.
- Weak, Leggy Plants: As plants become rootbound, they often form weak, floppy stems with increased internodal spacing. It’s normal for plants to stretch during the flowering period, but if you notice significant stretching during the vegetative period, you may need to transplant.
- Nutrient Deficiencies: Cannabis plants need a healthy root zone to take in nutrients from the soil. If you observe that the leaves of the plants are becoming yellow or brown, it may be a sign of a nutritional imbalance. By repotting them, you’ll give your plants fresh, nutrient-rich soil and more space for the roots to grow.
How To Transplant Cannabis Plants
- When your plant is ready for transplanting, give it some water one to two days beforehand. A little moisture will help to keep the soil intact when you pull the plant out of the pot.
- Prepare the new pot by filling the bottom with soil. Try to add enough soil so that the base of the plant lines up with the top of the larger container.
- Softly squeeze the old pot with your hands to get the roots to break free from the sides of the container. Don’t press too hard, or you’ll damage the root ball.
- Cover the soil with your hand, flip the plant upside down, and gently pull the root ball out of the pot. Support the bottom of the root ball with your hand to prevent it from breaking away from the plant. Doing this above a trash bin or tarp is a good idea to collect any soil that falls to the ground.
- Place the plant into the new pot and fill the sides and top with fresh soil. Softly pack down the soil and add more until it is approximately one inch from the top of the container.
- Lightly water the soil, making sure to disperse the water evenly throughout the medium.
- Optional Step: Add a layer of mulch to the top of the soil to keep the root zone moist and protected from the sun’s rays.
Pro Tip: Roots often grow into the material of fabric pots, making transplanting very difficult. We recommend using plastic pots for the seeding and vegetative growth periods and transplanting into fabric pots right before flowering. Some fabric pots have zippers or hook-and-loop fasteners on the side, making it easier to remove the root ball. If you insist on using fabric grow bags throughout the entire growth cycle, try to find some that can be opened from the side.
Final Thoughts on Transplanting Cannabis Plants
A healthy root zone is the key to a happy plant. By transplanting your cannabis plants at the right time, you’ll be able to maximize root growth and nutrient uptake. As a result, you’ll enjoy higher yields and more potent, flavorful buds.
What are your top tips for transplanting cannabis plants? Please share your advice in the comment section below. While you’re here, don’t forget to shop our selection of regular and feminized marijuana seeds.