Contain Yourself: Perfect Plants for Small Spaces
Garden designer P. Allen Smith shares his formula for container gardens--it's as simple as 1, 2, 3.
Using premium container-soil mix, fill your container about two-thirds full. Premium mixes contain water-retaining polymers and fertilizers; if the product you buy doesn't have these extras, add them yourself. I add water-saving gel crystals, which swell up when wet then slowly release water.