Correction...I didn't mean to write "SOIL" in the title...I meant to write "potting mix."

My question is...when should I transplant these into potting medium? Do I need to wait for a full root system to develop? What about the cutting with a full leaf...does that need nutrients in potting mix or will the Perlite/water do for now?

If they were mine i generally like to keep things simple and would just leave them be until many more roots develop before transplanting.
At that stage i dont give them nutrients or water or very little water at all.
Best Health
Martin

I prefer to wait until the root system is well developed. They can stay in cup quite a long time. Go to Figs4fun and read the propagation section and search both forums for related topics to your question. Tim

It's often a judgment call, but basically I would suggest that you pot-up or repot at the point when the soil in the root mass remains intact when you lift the plant from the container. Which brings up another point - try to use containers for propagating that will facilitate removing the growing cutting when required.

By judgment (above), I meant that you shouldn't be lifting the plant every few days to see if the soil comes out intact, because the practice of lifting the plant to inspect the roots sets the plant back.

Several studies have shown that allowing a plant to grow beyond this point ensures that the plant cannot grow to its genetic potential, within the limitations of other cultural influences. IOW, tight roots inhibit growth. (Dr. C. Whitcomb, et al)

Once root density has grown beyond this point, growth is permanently inhibited, at least as long as the condition is not corrected by judicious pruning of the roots at appropriate intervals. There is no significant advantage in potting up or repotting before this point, either.

Al

If it was spring or summer I would say you can remove them and placing in a pot with a slow release fertilizer with good potting mix. However having the plant indoors it will not promote much growth for you now. You probably can keep it alive until the days are a bit longer and temperatures are a little warmer.

Thanks everyone for the very helpful information...this place is great.

I am not questioning what Al mentioned above but if I am rooting a cutting (with average experience), the mere survival of the rooted plant is my biggest desire and a big mass of roots in a cup gives me that opportunity. Let the plant be bonsaid for a little while below its genetic potentials which can be taken care of later when the plant has well established roots and shoots by root prunning, root spreading etc.