There are a number of possible reasons:
Is the tree growing in the shade or indoors? Light is essential for fruit production. Foliage growth can occur in the shade, but leaves will tend to be larger than normal and shoots longer than normal. At least six hours of full sun a day is required. Provide 8 or more hours of sun per day for optimal fruit production.
If your tree grows at a rapid rate and has for years, it's possible that a rootstock sucker has taken over. Our citrus trees graft line can be seen as a diagonal scar between 4 and 8 inches above the soil line. Remove all shoot growth below the graft. These so-called "suckers" take vitality from the top of the tree (the fruiting wood). Especially on young trees, they are very vigorous. Remove suckers as soon as they are observed.
Have there been blooms on the tree that haven't set fruit, or small fruit that haven't developed to maturity? If fruit or bloom drop is excessive, proper watering is often the solution. Extremely hot, dry, windy weather will trigger fruit drop. Be sure trees are well watered in these situations. Excessive fruit drop accompanied by splitting fruit is the result of too much water uptake. Lack of proper fertilizer will also cause fruit drop. An undernourished tree cannot support fruit development.
Blooming and fruiting is dependent on sufficient light and heat. Citrus trees in a dark or shaded space may produce foliage but not flower. If you do not have a bright (preferably South facing) window, skylight or greenhouse, you may need to supplement with grow lights. For best results indoors, simulate California weather by providing a minimum of 8 hours of direct light each day. Grow lights can be used to supplement sunlight and may be left on to extend day length.
By far, the Meyer Lemon is the most popular. It is slightly sweeter than the classic commercial varieties (Eureka and Lisbon). Its thin skin and distinctive, mystical flavor combines lemon with a hint of tangerine. It is easy to grow, prolific and does not need a lot of heat to ripen the fruit. Bearss Seedless Lime is great for beverages and cooking. Kieffer Lime Leaves are used extensively for Thai cooking. Calamondin (Kalamansi/”miniature orange”), with its small tart orange-colored fruit and fragrant blooms is also very popular. Trovita Orange has sweet fruit in the spring.
Usually, once the trees are about three years old, they are mature enough to handle fruit production. Younger trees are capable of bearing, but doing so does slow branch and foliage growth, which are important for the tree's long-term development. See our Citrus Variety Information Chart for specific information by variety.
Since our trees are grafted, the scion (fruiting wood) is capable of flowering at a young age. Most citrus bloom in the spring, but the ripening times can vary greatly. See our variety chart for specifics about ripening. If fruit develops the first year, we often pinch the fruit off to encourage leaf and stem development. Generally a citrus tree will bloom in the spring if given adequate light, water and fertilizer. Each year as the tree grows; it will have more fruit producing capacity.
Some fruit drop is normal, especially in hot summer months. If fruit or bloom drop is excessive, proper watering is often the solution. Extremely hot, dry, windy weather will trigger fruit drop. Be sure trees are well watered in these situations. If you observe excessive fruit and leaf drop a few days after a heavy watering, the tree became too dry before it was watered. In the future, be consistent in your watering schedule. Protect from excessive wind exposure.
Yellowing leaves usually indicate either a lack of fertilizer or overwatering. Continued overwatering will cause root tips to rot, rendering the tree unable to take up nutrients. Total defoliation can result if the problem is not corrected.
Cut back on watering to the recommended rates and be sure to fertilize appropriately.
Citrus are heavy feeders and require a constant steady source of Nitrogen, especially to look good and be productive. Make sure you fertilize regularly according to label directions with a quality citrus/avocado fertilizer. Make sure the ratio of any fertilizer you use has a higher amount of Nitrogen, relative to the other two elements. A 2:1:1 (N:P:K) fertilizer, plus trace elements is ideal.
For lemon trees in particular, some yellowing and drop of interior leaves is normal. Lemon trees can grow very vigorously, and benefit from some judicious pruning to keep them bushy. New branches will form where you cut.
Leaf drop and twig dieback can be caused by lack of light or too much water. Outside, hot windy conditions can cause foliage stress.
Leaf drop and twig dieback can be caused by lack of light. Citrus trees need a minimum of 6 hours of full sun to grow. If growing indoors, it's possible that your trees will do better with a grow light for the winter. A sudden change in lighting or humidity can cause problems, so be sure to move your tree gradually from one spot to another, or from inside to out.
If your tree receives adequate light, and experiences leaf drop, improper watering is probably the culprit. A lack of water can cause the tree to dry out and lose leaves, while excessive watering can cause the roots to rot, so that they lose the ability to take water and nutrients up to the leaves. If you modify watering to provide even moisture, often the tree will recover, albeit slowly. A moisture meter is useful to be certain that watering is necessary, and can help you develop an appropriate watering schedule.
Should your tree lose all its leaves, don't despair. You can prune it back lightly to help push new growth; then, with improved growing conditions (adequate light, correct watering) it should recover. Remember also to feed regularly with a good citrus fertilizer (2:1:1 ratio or similar).
Check your tree regularly for pests. Severe infestations of scale insects, or mites can cause defoliation. Regular monitoring will help you to take action in time, before severe stress (defoliation) occurs.
This depends on where they are planted, and the care received. In general if you plant a semi-dwarf citrus tree in a container, over the years with good care it will top out in height at around 8-10 feet, depending upon variety. Pruning is always an option for keeping them shorter. Our Semi-Dwarf Citrus trees can grow up to 10’-15’ when planted in the ground, but are easily kept smaller if grown in a container or with judicious pruning
Here are some general guidelines:
In the ground, water deeply once a week.In outdoor containers, water deeply once or twice a week.Indoors, water enough to saturate the container (~ 1/4 - 1/2 gallon) approximately every 5-7 days, or less often, as determined by a moisture meter reading of 50% dry in the roots.
Vary watering as conditions change! A simple moisture meter, available at garden supply stores, will read moisture at the root level. This inexpensive tool can take the guess-work out of watering. See our complete watering guidelines for more details.
Keep in mind that all citrus fruits only ripen on the tree. In temperate areas, the best way to determine ripeness for oranges is to watch for the color to change, then check for a slight softening of the fruit. Lemons are ready when yellow, and generally hold on the tree for months. Because fruit coloration is triggered by cooling nighttime temperatures in fall, trees in tropical zones may not color up when ripe. The development of a waxy opaque sheen on the rind is another indicator of ripening. It may be necessary to taste fruit to be certain of ripeness. See our Citrus Variety Information Chart for specific information by variety.
For lemons and limes, the time from bloom to edible fruit is generally 6-9 months. For winter oranges and other citrus, it is generally 12 months. Keep in mind that all citrus fruits only ripen on the tree. One of the best ways to determine ripeness is to pick a fruit and sample it, since rind color can be an unreliable indicator. See our Citrus Variety Information Chart for specific information by variety.