Can I grow anything in the area under my outdoor stairs where very little light reaches?
You should test the light there because, of course, any growing thing needs light to survive. On a sunny day, hold your hand several inches above the ground. If your hand makes any shadow at all, there’s hope! Some good bets for this kind of densely shaded area are wild violets or Lamium, Bishop’s Weed, and Sweet Woodruff. The violets and Sweet Woodruff will produce flowers, if that’s what you’re hoping for, while the others will give you some nice variegated leaves. Now, a second challenge will be to make sure you get enough water to those plants. Regular watering under your stairs would be essential! Good luck!