Beautiful and functional, lemon trees (Citrus limon) add fragrant white flowers and edible fruits to the home landscape. They are the least cold-hardy citrus, and most do best in U.S. Department of Agriculture plant hardiness zones 9 through 11. Meyer lemons (Citrus limon 'Meyer Improved') may survive with protection in USDA zone 8, and possibly zone 7b. Other lemons hardy in USDA zones 9 through 11 include 'Eureka' lemon (Citrus limon 'Eureka'), which has fewer thorns than other cultivars, and 'Lisbon' lemon (Citrus limon 'Lisbon'), which is slightly more tolerant of cold than Eureka. They all have similar growing requirements.
A good landscape location for lemons has enough room to place trees at least 15 to 25 feet away from structures like homes and power lines. The site should be protected from north winds in the warmest part of your landscape. Lemons need full sun to produce the best fruit crops.
Lemons thrive in most well-drained soils. A soil pH between 5.5 and 6.5 is ideal. Lemon trees do not grow well in clay soils. To correct heavy clayey soil enough for lemons to thrive, you'd have to remove the existing soil and mix it with sand at a ratio of 1 part soil to 3 parts sand, then replace it in the planting location. When planting in sandy or other well-draining soil, adding compost or other organic amendments is not necessary.
Step 1: Prepare the Location
If you're planting in locations where there is a shallow rockbed under the soil, you'll have to break-up the rock when planting so the soil can drain. In other locations with poor drainage, such as a depression in the landscape where rainwater collects, create a mound of soil 3 to 4 feet tall and 4 to 10 feet wide, then plant the tree in the mound.
Step 2: Dig a Hole
For full-size lemons like 'Eureka' and 'Lisbon,' space trees 15 feet apart. Plant smaller varieties, like the 'Improved Meyer' lemon, 8 feet apart. When you're ready to plant, dig a hole 3 to 4 times wider than the container the lemon came in. Make the hole 3 times as deep as the container to loosen the soil.
Step 3: Plant the Lemon
Replace enough of the soil you dug out of the hole so the lemon is planted sitting at the same depth it was growing in the container. Fill in around the lemon's rootball, and tamp the soil down lightly.
Step 4: Water Immediately
Water the newly planted lemon slowly to thoroughly soak the soil. Continue watering every other day for the first week, then water one to two times a week for the next two months.
For the first two years, water lemon trees when there has been no rainfall for five or more days. Mature lemon trees only need water during severe droughts. Always water lemons deeply and slowly so the water has time to soak down through the root ball. Take care not to splash the leaves, flowers or fruit.
Like most other plants, lemons need nitrogen (N), phosphorus (P) and potassium (K) to thrive. As citrus trees, lemons also require micronutrients like magnesium, manganese and copper. For this reason, it is best to use a special citrus fertilizer formula to make sure you're meeting all their nutrients needs.
Use a slow-release granular form of fertilizer to avoid burning the roots with too much nitrogen all at once. Application rates vary depending on the product and the size of the tree. For a citrus food with an N-P-K ratio of 13-7-13, a tree 2 to 3 feet tall needs three applications a year with 3/4 pounds of fertilizer each time, while a tree 6 to 8 feet tall needs two applications of 2 1/2 pounds of fertilizer each time. Make the first application in late winter, then space the next applications three months apart.