Pictures of classic Italian gardens almost always show a row of container-planted lemon trees. To duplicate that look - or add a single lemon or other citrus tree to a small patio or balcony, start with the right size pot - a container taller than it is wide and one size larger than the nursery pot the tree came in. A 50-50 mix of quality potting soil and an azalea or other acid-plant soil mix will help the tree thrive. Pick a healthy tree - one with healthy leaves and new growth, plant it in the container, and water thoroughly. Water regularly thereafter when the top one or two inches of soil is dry