From 2014.igem.org

Repropagating Transformants

After transformation, the transformation plates usually contain many transformants, and so growth slows. The plants will usually not form gemmae until they are repropagated.

For repropagation, use 1/2 B5 + 1.2% agar plates, with selection if required. Use 5cm, deep petri dishes.

Protocol

1. Sterilise forceps using ethanol and flame.

2. Working in a laminar flow hood, gently remove a plant (with its rizoids) from the transformation plate and place onto the prepared plates.

It's OK if you transfer a bit of the agar from the old plate.

3. Seal with micropore tape.

It is recommended to always use freshly autoclaved media and freshly poured plates for this stage, to minimize the possibility of contamination.