Citrus trees are evergreen plants with bright green foliage and fragrant flowers. Valuable as ornamentals or orchard trees, citrus is also an excellent source of Vitamin C. Citrus trees are not difficult to grow, but do have certain requirements that need to be met. 

Temperature

Citrus are affected by cold and accumulated heat. Taking advantage of microclimates around your house may aid you in growing these cold-sensitive fruits.

Most tender to most hardy:

• Lime
• Lemon
• Grapefruit
• Bearss Lime
• Sweet Orange
• Mandarins
• Meyer Lemon
• Satsuma Mandarin
• Kumquat

The most tender foliage can be damaged at temperatures of 32°F, while the most hardy citrus can stand temperatures down to 18°F, but most fruit will be damaged at 26–28°F. If damaged by a frost, most citrus will still produce fruit the following year. 

Citrus also needs a certain level of accumulated heat in order to ripen. Since lemons are eaten for their acidic taste, they don’t need the accumulated heat in order to sweeten up. Therefore lemons are suited for cool, coastal climates. Grapefruit and oranges need a high-accumulated heat and only reach peak quality in hot inland and desert areas.  

Acclimating Your New Tree

Your new citrus tree must be slowly acclimated to its new home. After unpacking your tree, place it in a location that gets indirect light or no more than 2 hours of direct sunlight (morning sun is best).

In a week you can move your tree to the permanent location. Citrus will drop some of their leaves when stressed. Do not worry, this is common and it will recover. If during the acclimation period the temperatures are going to be below 40°F, bring your tree inside.

Planting Instructions

Fruit trees are a lifetime investment and caring for them properly, right from the start, will insure years of enjoyment and productivity. The greater the investment in early care, the less maintenance that will be required as the tree matures. 

It is best to plant your tree early in the morning. Dig a hole twice the width of the root ball. Place the tree in the hole so the root crown, where the roots meet the trunk, is high.

Add the fill soil (mixed with high quality soil conditioner or organic matter) back in and water thoroughly. Citrus must have well-drained soil, as they are sensitive to waterlogged soils.

If you have poor drainage, try planting it in a raised bed or container. They do need adequate moisture, so if planting in containers, use a pot that is at least 18 inches in diameter. 

Check out Smart Pots; soft sided, fabric containers that have the rigidity to hold its shape and even support large trees. Smart Pots have the unique ability to air-prune and enhance a plant's root structure.

A soil analysis is also recommended to determine any soil deficiencies, but this can be delayed until the tree has begun to establish itself. A gradual application of proper soil amendments will suffice if proper sunlight and drainage are available from the start.

Watering

Citrus like soil that is moist but never soggy. If growing in the ground water deeply and less frequently. Apply a thick layer of mulch (2-3”) to help conserve water and make sure to keep mulch away from the base of the tree to prevent rot. For potted citrus, it is fine to allow the top of the soil to dry, but make sure the pot can drain and the tree is not getting waterlogged. 

Fertility

For mineral soils that are well-balanced, a yearly application of compost and an organic fertilizer high in nitrogen is ideal. Citrus Mix is designed to nourish both citrus trees in home orchards and containers. Fertilizer should be applied in early spring, mixed into the the top 6” of the soil in a broad ring underneath the drip line of the tree. 

In the long-term, calcium, magnesium, phosphorus, and potassium, along with sufficient nitrogen, will significantly enhance tree health and fruit quality. 

Citrus also benefit from application of micronutrients such as zinc, iron, manganese and magnesium, if these are at low-levels in your soils.

Container grown citrus might need more frequent applications of nitrogen since watering may leach nitrogen. Periodic soil testing will show whether pH and nutrient needs are being met.

Frost Protection

To avoid damage by frost, protect trees with row covers or frost blankets. If trees are planted in containers, move them inside or to a greenhouse during cold weather. 

Pruning

Citrus need little pruning, only its dead or broken branches. You may need to remove suckers from younger trees. Lemon trees need the most pruning of their vigorous branches. 

Harvesting

New young trees will begin to fruit in their third or fourth year. In general, the hotter your climate, the earlier you can harvest. Fruit grown on the coast ripen last. Color is not a good indicator of ripeness. Citrus fruit ripens on the tree and the best way to tell when to harvest your fruit is by taste.