We moved in too late to start a garden this year, so on a whim I decided to grow two varieties of lettuce in pots on an inside windowsill. In each pot I used the same potting soil and fertilizer, and same amount of seeds in each. They are lined up on the same windowsill.

What a difference the amount of sun that each pot gets throughout the day makes on growth. Starting with the upper left, the most to least sun-exposed lettuce, going clockwise. The two on the left are the same variety, and the two on the right are the other variety.