A planter needs to try to use every inch to good effect in a small garden. Every element of hardscape represents several feet of space that can't be used to grow plants. Every large specimen tree represents several smaller plants that can't be grown. Know your priorities before you plant your small garden, so that you can grow the plants you really want.
Bamboo Privacy Plantings
Use bamboo to create a privacy screen. Plant clumping bamboo in an elevated planter to quickly create a small screen between a particular window and your garden. For a broader garden screen, block out a narrow rectangular section to create a living bamboo fence. Block off an area about 6 inches wide and as long as you want it with metal or plastic edging going half a foot below the ground. Plant running bamboo every 2 to 3 feet within this area and keep the soil moist. Within a season or two, the bamboo will spread and create an entire living privacy wall.
Tailor your planting to your small garden space by using small plants. Air plants or tillandsia are small plants with unusual blooms that do not need soil and can grow almost anywhere. Grow them in the cracks in garden walls or from the sides of sculptures to create unexpected splashes of color. Add miniature cacti and succulents for sunny areas of your small garden. Grow small wildflowers, low ornamental grasses, thyme, basil and other small herbs and other compact plants in racks or vertical columns of hanging planters around your garden. The miniature plants will let you grow more and make your garden look bigger than it is.
Most vegetables require 6 inches or more between plants. Purdue Yard and Garden recommends interplanting fast- and slow-growing crops to get twice the density. For example, grow radishes and carrots in intersecting grids sharing the same space. Harvest the radishes when they are ready in four weeks and remove the radish plants. The slow-growing carrots will just be beginning to mature, and will have plenty of room to continue growing.