Miracle grow is only okay for cannabis plants but be sure to flush the plants at least 7-10 days before harvest to clean them as I have heard some horror stories about people getting sick after smoking plants that have been poisoned with miracle grow. There is a reason you never see miracle...
As long as it's not too tight and the stem has plenty of room to grow you should be fine. I use a big match stick with very fine sowing thread lightly tied to it to fully support it but not counteract her growth.
This happened to me on a grow in the middle of nowhere, 15 purple power plants around 4-5 cm tall each all dug up by something or someone. Very devastating.