What is the weather like where you are? Here its mild and damp and I would plant straight out. The garage will be dark. Is there a reason why you don't want to plant out. If its mild and damp near you and you don't want to plant out straight away, they might be better stood out in the garden than in the garage
Give them a good soaking in a bucket for two days, outside during the day and inside at night, then plant them but cover them at night with frost protection and straw round the base.