How to Transplant Cannabis Into a Bigger Pot: Why, When and Step by Step

Transplant your cannabis into a bigger container once its roots fill the current one: for seedlings that's usually at four or five sets of leaves, and in veg a good rule is about 8 liters (2 gallons) of soil for every 30 cm (1 ft) of plant height. Moving up in stages keeps roots from rotting in too much wet soil early on and from getting root-bound later, which stunts growth and flower production.

Why is transplanting important?

Plenty of growers plant their seeds in the same containers they plan to finish them in, so they never have to transplant. That can save some stress, but small plants don't have a big enough root system to fill a large pot, so the soil can stay too wet and nutrients can get lost. When water sits in the pot without being taken up, the roots can rot, which does serious damage to the plant.

Growers who germinate seeds in smaller pots and transplant as needed protect their plants from rot. The catch with small pots, though, is that they limit how far the roots can spread. For plants to thrive, their root systems need to stretch out as much as possible. Container size determines how big a root system can get, which is why cannabis plants need transplanting to reach their potential.

Without transplanting, cannabis plants can get root-bound. That's bad news for plant development and stunts flower production. Plants in a pot packed with roots may show reddish stems and are likely to run into nutrient deficiencies.

A cannabis plant with a crammed root system dries out much faster. The roots suck up all the available moisture, often before the grower has time to water again. If these plants don't get moved to a bigger container, they risk nutrient deficiencies and disease, and they can even die.

When should you transplant weed plants?

If a cannabis seed didn't germinate directly in soil, it should be planted right after it sprouts. Growers who start plants in small containers can tell when it's time to transplant by counting leaves: the plant should have four to five sets of leaves, not counting the first pair (the cotyledons). Once it hits that point, the roots have outgrown the starter cup and the plant should be transplanted as soon as possible.

Other growers germinate their seeds and grow their plants in a small to medium container, keeping them there until a few weeks before flowering starts. In the last few weeks before a cannabis plant switches to flower, it grows exponentially in size and volume. During that stretch, the roots spread a lot farther, which means the plant needs a bigger container.

Many containers have small drainage holes in the bottom. Those holes also let you check on the health of the root system. If you see discolored roots poking out of the bottom of the pot, the plant may be root-bound and should be transplanted right away.

How to transplant weed plants

Growing cannabis in properly sized containers and transplanting as the plants get bigger is the best way to grow. Transplanting does come with some risk, though. Root systems are extremely sensitive, and damaging them can be disastrous, even fatal, for the plant.

Young seedlings have delicate root systems that are prone to disease. Wash your hands or wear gloves when handling them, and make sure your work area is clean.

Wet soil is heavier and likely to pull on the roots and tear them if you try to transplant while it's soaked. It's best to let the soil dry out enough to pull away easily from the sides of the pot, but not so much that the plant wilts.

Before transplanting, make sure the new container has enough soil or other growing medium to support the root system and hold the plant upright. There should be enough room to set the young plant in safely without bumping or damaging its roots.

With clean hands, hold the base of the plant firmly and flip the starter pot upside down. Gently loosen the soil from the container and be very careful not to disturb the root system. The first transplant is the riskiest and can quickly send the plant into shock if the roots get jostled too much. It's just as important to avoid strong, direct light during the transplant, since that can also shock the roots.

Once the plant is out of its original pot, set it into the new container filled with growing medium (soil or whatever you've chosen). Holding the young plant steady with a gentle grip, fill the space around the roots with more medium. Cover the stem up to the first set of shoots with loose soil or growing medium.

Once the plant is transplanted, water it generously with pH-balanced water. Make sure it's soaked until water drips out the bottom of the pot. Keep a close eye on it for a few days for signs of shock before adding any nutrients.

Transplanting during the vegetative stage

When you transplant a cannabis plant in veg, plan on a container that holds about 8 liters (2 gallons) of soil for every 30 cm (1 ft) of plant height. Plants should have completely filled their current pot before you move them up.

Plants are great communicators, and they'll show signs of stress when they get root-bound. If you see wilting, nutrient deficiencies, discolored leaves or brown roots, it's time to get the next pot ready.

In the days before transplanting, cut back the nutrients you're feeding by at least half. That helps protect plants from shock when they move into a new container.

When transplanting in veg, be careful not to pack the soil down too hard. Overly compacted soil blocks drainage and damages roots. You can repeat this as many times as needed during veg, but keep in mind that the more often you do it, the more risk for the roots.

The root systems of developing cannabis plants are sensitive and easily damaged, both by cramped growing space and by rough transplants. A successful transplant is a key part of growing the best plants with the biggest possible yield.

How do you transplant a bigger cannabis plant?

Transplanting a bigger plant, or even a young seedling that's outgrown its pot, takes care and planning to pull off. Here are a few tips for a successful transplant:

1. Prep the new container: pick a container big enough for the plant's current size with room to grow. Make sure it has drainage holes so water doesn't pool. Prep the right growing medium, like a nutrient-rich, well-draining soil mix.

2. Prep the plant: water the plant lightly before transplanting so the root ball slides out more easily. If it's in a container, tap the sides gently to loosen it and make it easier to remove.

3. Transplant carefully: hold the plant gently by the stem or leaves and avoid squeezing the base of the stem. Pull it out of the old container and set it in the new one at the same depth as before, or slightly deeper to encourage new root growth. Fill in the gaps with your prepped medium, pressing lightly so it's held firmly in place.

4. Water properly: after transplanting, water the plant carefully to help it settle into its new home. Don't overdo it, since too much water can cause root problems. Keep the medium slightly moist for the first few days, then go back to your regular watering schedule based on what the plant needs.

5. Give it a good environment: put the transplanted plant somewhere with the right amount of light, temperature and humidity. Avoid exposing it to extreme conditions or sudden changes.

Keep a close eye on the plant after transplanting and watch for any signs of stress. If it looks droopy, you can give it extra support with things like a mild nutrient solution, the right fertilizer and making sure it's getting enough light and airflow.

Follow these tips, give your plant the care it needs, and you'll be able to transplant even a big plant successfully and keep it growing strong.

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