I have a cutting under a plastic bottle. How long do I keep it there?
The bottle acts like a miniature greenhouse. If you cut the bottom of the plastic bottle off to make this little greenhouse, then you will be able to take the cap off periodically to help regulate the moisture buildup inside. So leaving the bottle in place for the first 5 to 6 weeks is important to get the rooting process going. Once that is going well you will start to see dome new growth. Once new growth is seen wait at least a week or two before taking the mini greenhouse off. Even then only take it off for an hour at most the first time and put it back on. All changes in its environment should be slow and methodical. Rapid changes can spell death for the new little rose. Here is a link to an article I wrote on this topic for you: https://www.gardeningknowhow.com/ornamental/flowers/roses/roses-from-cuttings.htm