Grow sweet strawberry in a vertical PVC tube is great solution for small garden or yard. Vertical planter will save you a lot of space, at the same time keep plants out of reach from garden insect pests AND enable you to switch to hydroponics.
Igelhaus bauen - build a nest for hedgehogs in your garden
Kitchen Scraps You Can Regrow - may need dirt.not just water. But it would be kinda cool to grow green onions and fennel on the window sill.