I love gardening but I'm a total novice, so any help/advice would be greatly appreciated.
Last spring I sowed Aquilegia vulgaris 'William Guiness' in a seed tray in my windowsill. It took quite a long time before anything started to grow and when it did it stayed the same tiny size for literally months. A few weeks ago suddenly they shot into action, I planted them out in separate little containers, and they seem very happy, the biggest ones more than 12 cms in height (see picture).
Now what do I do with them? Can I still plant these outside now, or is that too late? Is it better to keep them until spring on my windowsill, or do I put them outside in a little greenhouse on my gardentable?