Inside or outside doesn't matter, IMO.
I've never tried rooting directly into soil. Keep 'em well watered and hope for the best.
Even if they never root, a cutting will usually stay looking healthy for several weeks.
I actually have cloned directly to outdoor soil (by accident of course).
See I did a heavy trim and threw all the tops and a couple days later I noticed the tops had turned up just laying there on top of the soil. I figured 'what the hell, why not' so I stuck them in the ground about an inch without any rooting hormone. This was about two months ago in march. Since then I have been watching them slowly die off, except a couple werent withering away as fast.... hmmm, did it work?
As of right now the ones seemingly wasting away slower haven't gotten worse over the past two weeks.
"Okay? Let's test them." I thought to myself
Low and behold if I tugged upward on them with the lightset pressure they wouldn't budge. Success!!!
Short story.... true story
Now this doesn't answer your question about the root length and time but what I can tell you is even against all odds there are still some that can make it (about 20% and 4 weeks in my case). However... I estimate the roots to be at least 5 iniches in length and would feel 100% confidant about uprooting for a container or hydro grow.
If you are cloning in a container already with normal backyard soil then you should wait till you can pull the mass out and physically see roots "circling" the container. Once you have reached this point then I suggest you go a size bigger and use a potting mix.
If you are in the ground and don't want to go through the hassle of transplanting them and they are healthy just leave 'em there.
I grew it last year also but it was really small cause it was being abused so I rescued her and brought her home. She was little but loved the taste so found one in a store this year so I got my hands on one lol
Stay away from water in the soil, spraying with water is ok a couple times a day depending on conditions??? No nute's and no hot soil!!! 75 to 85 degrees is sweet. I use a gel and powder i cut at a 45 angle and put at least 2 nodes in gel and split the bottom slightly peel back the calcium layer put it in soil wet soil and in a week wala clones, never lost one yet. But there is always a first. Also no intense halides i use floro gro-lux. Just sayin.
Well it's outside in a green house with no heater so it dose not stay close to that in there but the plant I took it from was also used to current outdoor weather. I'm hoping for the best. I didn't use any rooting gels or powders, just left it in water for a day then put it in my potting soil.