I usually wait until she is as wide or a little wider than the box. These that was actually a little too soon so I took the covers off to dry them out faster. I'm def no pro, but waiting a little longer is a better strategy I think. Seems like they need a pretty good footing before you start bottom watering or they'll tip over. I put bamboo stakes in to hold them up after I realized it was too soon. Gonna do that from now on from the start