These are the dends your wanting to possibly repot if size is incorrect???
First when you repot dends you need to make sure that you have 3 pseudos grouped to repot, as well as repotting along the side of the pot so new pseudos will grow toward the middle of the pot.
The first 2
s are they pseudos only, with or without a rooting system? If a pseudo only these should have placed in a 2 inch pot with mostly sphag to keep moist and place in a plastic air filled baggie for approx 1-2 months. If it does have a rooting system than it can be free with the other orchids in your collection, but the pot needs to come down a size or two.
The 2nd set of
s, I would leave well enough alone, looks fine in what it is in and looks extremely happy.
The 3rd set of
s, if you are planning on repotting, this is where the "rule of thumb" comes in at that no less than 3 pseudos in a split for Repotting. Dendrobiums like to be somewhat root bound. Allow a very limited space for new growth. Use a coarse Fir Bark mixture that allows perfect drainage, easy on the water for 6-8 weeks.
Dendrobium Pot Size
Linear Mode
