Dendrobium Nobile seedling Winter care?

[Diane56Victor]

I have some Nobile seedlings, none are over 5 or 6 inches tall.
I know that mature Nobile should stop getting fertilizer and get limited water over the Winter period, also have a cooler time to make the plant bloom.
This wouldn't apply to seedlings would it?
I've listed some relevant facts about my seedlings.
These seedlings are doing all kinds of things, some have new growths, others have leaves going yellow, some even have both things going on.
Root growth on all is excellent.
Some are in bark and some in some commercial sponge type material.
They were purchased from a warmer area of Australia and as we were heading towards Autumn when I bought them I decided to keep them indoors, possibly repot in the Spring as they are in extremely tiny pots.
They are in a West facing window and the temperature in the room (no heating) at 7am this morning was 15C (59f)
We are currently in the middle of Autumn here in South Australia.
We CAN get lowest outside night time Winter temps of 5C (41f) and daytime high of 10C(50f) although generally it is a bit warmer. With the strange weather pattern this past year, who knows what this Winter could be.