Grow citrus where they'll get plenty of sun and in acidic, well-drained soil that's enriched with organic matter. Many experts say that growing the plants in soils rich in organic matter and using balanced organic fertilizers produces better-tasting fruit. Most citrus do not tolerate temperatures below 40 F. In areas where citrus are marginally hardy, plant them in raised beds (where the soil warms more readily) or on the south or west side of a wall or building so that extra heat radiates onto the tree.
Gardeners who live in the North need to grow citrus indoors. Site plants where they get lots of light (direct sun is fine in most areas) and away from drafts that come from windows, doors, or heat registers. The plants prefer winter temperatures of about 65 F during the day and a few degrees cooler at night. Grow citrus in large containers that have drainage holes at the bottom. Use an acidic potting mix, such as a peat-based mix.
In areas that have alkaline water, it will be necessary to periodically use an acidifier to keep the potting-mix pH from getting too high. Water citrus enough to keep the soil moist but not wet. If you water too much, the plant roots will die and rot. Most citrus don't need to be trained as rigorously as temperate trees such as apples, pears, and cherries. With citrus, keep these things in mind.
Maintain an open growth habit by removing overlapping or excess shoots. Remove older, bearing wood to continually stimulate new growth, because most old wood becomes unfruitful after a while. Cut off shoots or limbs at the point where they join to another limb. Cutting back the ends of shoots instead of removing old branches can cause lots of small, brushy growth that blocks sun from the interior and encourages disease.