When to transplant seedlings

Most growers transplant cannabis seedlings about 10–21 days after emergence, once two key signs appear: (1) the first or second set of true serrated leaves has fully developed, and (2) feeder roots are visible through the drainage holes of the starter cup.

Transplanting too early shocks the seedling because the root mass isn't strong enough to handle disturbance. Transplanting too late means the roots circle the starter pot and growth stalls.

Best practice: water the seedling 2–4 hours before transplant so the root ball is moist and cohesive. Pre-moisten the destination pot. Squeeze the sides of the starter cup gently, invert into your hand, and lower the intact root ball into a pre-dug hole. Backfill, water in lightly. Avoid breaking up the root ball.

Seedlings transplanted at the right moment recover in hours. Done too aggressively or too early, they can stall 5–10 days.