When and how to repot seedlings

Repotting cannabis seedlings and adult plants is an important step in the growing process, promoting root growth and helping the plants develop optimally. Here's a detailed guide on when and how to repot your cannabis seedlings:

When should you repot?

1. Root development

  • Roots growing through drainage holes: A clear sign that it is time to repot is when the roots grow out of the drainage holes at the bottom of the current container.
  • Root ball formation: When you carefully lift the seedling/plant out of the pot and see that the roots enclose the entire root ball, it is time for a larger pot.

2. Plant size

  • Leaf development: When the plant has developed about 3-4 pairs of leaves and has reached a height of about 10-15 cm, this is a good time to repot.
  • Lack of space: If the leaves begin to grow beyond the edge of the current container or shade each other, the plants need more space.

3. Growth phase

  • Vegetative phase: It is ideal to transplant seedlings/plants in the early vegetative phase before they become too large and the risk of transplant shock increases.

How should you repot?

1. Preparation

  • New pots: Choose pots that are large enough (at least twice the size of the current pot) and have good drainage holes.
  • Soil/Substrate: Use high-quality soil or a suitable substrate with good drainage. A mix of potting soil, perlite, and coco fiber works well.
  • Tools: Prepare all necessary tools: gloves, a small shovel or spade, and possibly a knife for loosening the roots.

2. Repotting process

  1. Watering before repotting:
        • Water the plants thoroughly a few hours before repotting. This makes it easier to remove the plant from the old pot and minimizes stress on the roots.
          • Preparing the new pot:
            • Fill the new pot halfway with fresh soil or substrate.
            • Make a depression in the center for the seedling's root ball.
          • Removing the seedling:
            • Gently hold the plant at the base of the stem.
            • Turn the old pot upside down and tap the bottom and sides lightly to loosen the soil.
            • Pull the plant out carefully, avoiding pulling on the roots.
          • Examination of the roots:
            • Check the roots for signs of disease or pests.
            • If necessary, carefully loosen any matted or tangled roots with your fingers or a clean knife.
          • Inserting into the new pot:
            • Place the seedling into the prepared hole in the new pot.
            • Fill the rest of the pot with soil and press it down lightly to avoid air pockets.
          • Watering after repotting:
            • Water the plant thoroughly to ensure the new soil settles well around the roots.
            • Be careful not to overwater; the substrate should be moist but not soggy.

          Aftercare

          1. Lighting conditions:
            • Make sure the plants receive sufficient light after repotting (18 hours of light/6 hours of darkness during the vegetative phase).
            • Avoid direct, strong light immediately after repotting; this can cause additional stress.
          2. Temperature and humidity:
            • Maintain a constant temperature between 20°C and 24°C.
            • The relative humidity should be between 50% and 70%.
          3. Surveillance:
            • Watch your plants closely for signs of stress (e.g. drooping leaves) in the first few days after repotting.
            • Give them time to adjust; slight growth delays are normal.

          Conclusion

          Proper timing and careful handling when repotting your cannabis seedlings are crucial for healthy growth and strong plants. By following these steps and paying attention to your plants' needs, you can ensure they thrive and are ready for a successful vegetative and productive flowering phase.