Up-potting is the practice of moving a plant through a series of larger containers, for example a 0.5 L cup, then a 3-4 L pot, then a 15-25 L final pot, as roots fill each one. The idea is that a small root system in a small volume of medium wets and dries quickly, which keeps roots oxygenated and reduces the overwatering risk of a seedling in a huge, cold, wet pot.
In practice
Up-pot when white roots reach the wall and the root ball lifts out intact, but before roots circle densely. Each move should go to roughly two to four times the volume. Many growers skip the middle step and go cup to final.
The alternative is planting straight into the final pot and watering only a small circle around the stem at first; that works well and avoids handling. For autoflowers GenetixBay recommends the final pot from day one.
Don't confuse with
- Transplanting: the general term; up-potting is a transplant into a bigger pot.
- Root pruning: deliberately cutting roots to keep a plant (often a mother) in the same pot.
