Plant a new lemon tree with its bud union above the soil. The soil around the tree should be level or higher than the rest of the nearby garden. Don't create a basin around the tree to hold the water for irrigation, as this practice encourages root rot. Instead, build a ring around the tree trunk using soil taken from another area of the garden. Make the walls of the ring about 2 inches high and thick and about 2 feet across.
Fill the irrigation ring with water immediately after planting. Do this gradually, and replace any soil that washes away after settling during the first watering.
Water the tree about every three days during the first two weeks after planting by gradually filling the irrigation ring with water.
Remove any weeds or grass growing within the circle of the irrigation ring.
Decrease the watering intervals over the next two months until irrigation occurs once every seven to 10 days. During this time the irrigation ring will gradually dissolve. Don't rebuild it; the tree will be considered established once the ring has disappeared.
Avoid fertilizing the lemon tree during its first year. According to Julian W. Sauls, Professor & Extension Horticulturist, one capful of ammonium sulfate (21-0-0) divided in three to four applications during the year is sufficient fertilization.
Protect young trees from severe cold by covering the tree with a tarp or burlap.
Bury the bud union in soil if frost is expected. This is considered a short-term strategy to protect the tree from frost. Uncover the bud union when the danger of frost is over.