As the tiny house trend grows or as empty nesters downsize to a condo, vertical gardening as a space-saving tactic will gain popularity. Some great ways to exercise your green thumb without a lot of room include mounted plants like the staghorn fern, wall planters for succulents, "living" walls, hanging baskets or retro macramé plant hangers for houseplants, window boxes or boxes that fit over a patio railing, and DIY pallet gardens that can lean or hang on fences or walls.