My seedlings are growing upwards!

The fact that the seedlings are growing upwards is a good indicator of a lack of light, the seedlings are therefore stretching to seek light. If your seedlings are placed near a window, this must surely be due to the filter created by the glass and especially to the length of the day, days etiolate the plants. You can carefully remove your seedlings using a stylus or a pencil and transplant them into another deep clod of potting soil to cover all the etiolated part. If it is not freezing in your garden, you can place them in a very bright frame to take advantage of maximum light and the full length of the day.