Lillies - When to plant in garden?
 

I am absolutely new to gardening and am trying to make the most of my small front garden. Approximately 4 weeks ago, I planted 2 lilly bulbs in a small plant pot and placed them on the porch window (nice and warm). These have also been watered regularly. The bulbs have grown and the stems from the bulbs are approx 10-15cm in height.

I'm just wondering when I should transfer these bulbs from the plant pots into the ground in the front garden? Also, how many flowers do you get from one lilly bulb? I am assuming you get more than one flower.

Sorry if my questions sound idiotic but as I said, I'm new to gardening.

BTW, I live in the North West if that helps