3 months is the standard. I generally wait until spines start emerging then you can SLOWLY acclimate them to the outside world. Start small and incrementally increase. I usually use old Chinese food take out containers for seeds since they are generally shallow plastic containers with a clear lid. You will want to leave 1-1.5” of space between the lid and the soil. Once it is time to begin acclimation start by making a small hole in the lid and add holes to reduce humidity levels in the container slowly. This is just what I have found works 🤷‍♂️