How to Grow a Lemon Tree
Lemon Tree Components
A lemon tree consists of two main parts:
- The Rootstock: Includes the lower trunk and the root system beneath the soil surface.
- The Scion: Comprises the main trunk, branches, leaves, and fruits.
The choice of rootstock depends on its economic value and the grower’s preference. Roots typically grow from seeds, but they can also develop through tissue culture or grafting methods, such as scion grafting or budding grafting. These methods help achieve desirable traits in a single tree, such as improved fruit quality and size, adaptability to unfavorable soil conditions or cold weather, and resistance to diseases and pests.
Citrus trees, including lemon trees, generally have poor productivity when grown on their own root systems. Thus, grafting is commonly used to enhance their adaptation to soil and surrounding conditions. The T-budding method is the most popular grafting technique, where the trunk is grafted a few centimeters above the seedling rootstock.
Seeds from citrus fruits can also be planted to grow trees, but they usually take several years to produce fruit. Moreover, fruits produced from most citrus varieties used as rootstocks are generally inedible and are only used for propagation purposes.
Planting Lemon Seeds
Lemon seeds can be planted using either purchased seeds or seeds extracted from ripe citrus fruits. The fruit should be rinsed thoroughly before extracting the seeds using a 20% diluted sodium hypochlorite solution. To remove the fruit tissue from the seeds, the seeds can be briefly treated with diluted potassium hydroxide or soaked overnight in an enzyme pectinase solution. The seeds must then be sterilized and washed with water to prevent exposure to potential pathogens.
The seeds should be spread on aluminum foil or non-stick paper to dry away from direct sunlight. They can then be stored in polyethylene bags at a temperature between 4–10°C. Fungicides can be used to protect seeds stored for extended periods. Seeds can also be planted without drying, but this may negatively affect the success of the plant’s growth.
Seeds are sown in sterile containers at a depth of 6.5–13 mm (0.25–0.5 inches). Seedlings typically appear within 2–3 weeks under ideal growth conditions, such as warm soil, sunlight, and adequate moisture. To enhance germination, the seed coat can be removed or the seeds can be soaked in carbonated water for 8 hours before planting. The plant will develop a single root, and branches should not appear on the tree’s trunk within 15–20 cm (6–8 inches) above the soil surface.
Grafting a Bud Onto the Tree
Budding and scion grafting are the most important propagation methods for fruit trees. These methods are used when layering (enclosing part of a branch in soil to develop roots while keeping it attached to the parent plant) or cuttings are not feasible.
Grafting involves the union of two plants with distinct genetic characteristics to grow as a single plant, resulting in improved traits compared to the original tree. Budding is typically done when the rootstock is actively growing, allowing the bark to slip easily from the wood. This usually occurs from April to November, depending on the plant’s location. The seedling’s trunk diameter should be about 6–10 mm (0.25–0.4 inches).
Before grafting, the rootstock should be fertilized and watered adequately, and the grafting area should be pruned to remove thorns. The bud to be transferred should be located 12.5–20 cm (5–8 inches) above the base of the trunk.
The grafted parts are joined and secured tightly using rubber or tape, depending on the grafting technique:
- Whip graft: The bud is grafted onto a rootstock piece of equal diameter.
- Cleft graft: The bud is inserted into a rootstock piece with a diameter of 7.5–10 cm (3–4 inches).
- Bark graft: Used for plants that are difficult to graft, typically in spring when the bark peels easily.
Grafting wax is often applied to prevent the graft area from drying out before it heals.
Transplanting Lemon Trees from Pots to Soil
Lemon tree seedlings are often sold in pots and can be planted at any time of the year. However, planting them from fall to late winter is preferred, as this helps the tree adapt to heat and drought by spring and summer.
Most citrus trees can grow in pots without soil, relying instead on a suitable amount of peat moss. However, extended growth in this medium can weaken the tree. To address this, about 3 cm (1.2 inches) of the medium around the root ball should be washed off before planting the tree in soil. This ensures that the roots are in contact with the soil for optimal growth.
Preparing the Planting Hole
The depth of the soil plays a crucial role in the growth and survival of citrus trees. While the root is resistant to rot, the trunk is more susceptible, especially if the graft union is close to the soil surface. This can lead to tree death from rot.
The hole should be cleaned of grass within a diameter of 1–1.5 meters (3.3–5 feet). The depth of the hole should match the root ball’s depth in barren areas or be about 3 cm (1.2 inches) shallower than the root ball’s depth in grassy areas.
Place the tree in the hole without mixing the backfilled soil with compost, surface soil, or other materials, especially if the soil is acidic and suitable for citrus trees. Fill the hole halfway with soil, water to settle the soil around the roots, and then continue backfilling. Ensure the root ball is covered by 1.25–2.5 cm (0.5–1 inch) of soil to protect it from rapid drying and exposure to air.
Caring for Newly Planted Lemon Trees
- Watering: Water newly planted lemon trees 2–3 times per week during the first week. Afterward, water 1–2 times per week, depending on the season, soil type, and rainfall. The soil should be watered when it feels dry to a depth of about 3 cm (1.2 inches).
- Weed Control: Keep the area around young trees free of weeds, as they compete for nutrients. Avoid using organic mulch near the tree, as it can cause rot. If necessary, keep mulch at least 30 cm (12 inches) away from the tree.
- Pruning: Lemon trees usually don’t require pruning, as they are sold pre-pruned. However, remove any sprouts that appear on the trunk or rootstock.
- Cold Protection: Young trees can be protected from cold by mounding soil around the trunk during the first 2–4 winters. This soil should be removed in early spring.
- Frost Protection: Avoid planting lemon trees in low areas where frost is more likely. Keep the soil beneath the tree clean and moist to reduce frost damage.
- Fertilization: Apply fertilizers three times during the growing season using suitable options such as ammonium sulfate, ammonium nitrate, or urea. Spread the fertilizer 15–90 cm (6–35 inches) away from the trunk and water thoroughly afterward.
Overview of the Lemon Tree
Lemon trees, both green and yellow varieties, are among the most acidic citrus fruits. Despite their similar appearance to other fruits, their acidity level is unmatched. Lemon trees belong to the order Sapindales and the family Rutaceae, which includes over 2,070 species in 160 genera. These plants thrive in warm tropical and subtropical regions, often found in semi-arid forests.
- Lime Tree (Green Lemon): A small evergreen tree that can grow up to 5 meters (16 feet). It produces greenish-yellow, oval-shaped fruits.
- Yellow Lemon Tree: Grows to a height of 3–6 meters (10–20 feet). The tree has fragrant flowers, and its fruit is oval-shaped with a slightly pointed end, measuring 7–12 cm (2.8–4.7 inches) in length.
