This genus includes oranges, lemons, limes, tangerines, grapefruits, etc. Commercial citrus cultivation usually involves grafted trees. The desired fruiting cultivars are on their rootstocks, which were carefully selected for disease resistance and hardiness.
Citrus fruits' color only develops in climates with a cool winter. In tropical regions, they remain green until maturity, hence the tropical "green oranges". It's important to note that the terms "ripe" and "mature" are usually used synonymously, but they actually mean different things. A fruit cannot ripen until it reaches maturity. A mature fruit is one that has completed its growth and ripening phase, reaching optimal quality for consumption. Ripening is the term used to describe the changes that occur within the fruit from the time it reaches maturity to the beginning of decay. Citrus fruits don't go through a ripening process in the sense that they become "tree ripe." Some fruits, like cherries, physically mature and continue to ripen on the tree. Other fruits, like pears, are picked when mature but before they ripen, they continue to ripen off the tree. Citrus fruits pass from immaturity to maturity to over-maturity while still on the tree. Once they're separated from the tree, they won't increase in sweetness or continue to ripen. The only change that happens after picking is eventual decay.
With oranges, color cannot be used as an indicator of ripeness. Sometimes the rinds turn orange long before the oranges are ready to eat. Tasting them is the only way to know whether they're ripe.
- Shelf Life: Water plants thoroughly, letting excess water drain through the bottom of the pot. Transplant into larger 12" containers separately.
- Plant Preparation : Cut away any yellow or brown leaves or broken stems that may have occurred. Branching out will rapidly follow any pruning.
- Potted Plants : Re-pot the plants into larger 12" pots separately. You can gradually transplant one pot size per year up to 20" in diameter.
- Soil: Use bagged potting mixes for houseplants that will drain well. Most garden centers carry various brand names with perlite, vermiculite, soil, and sand.
- Garden Preparation : If you live in a climate where temperatures rarely dip below freezing, citrus trees can be planted directly into the garden slightly above the soil line by 1 – 2". If your soil is clay-like, amend it with a standard garden soil for adequate drainage.
- Plant Spacing: If planting into the garden, space trees 5' apart. If planting into a container, allow for adequate air ventilation on the deck or patio.
- Plant Height & Width: These grafted dwarf varieties grow 1' per year, up to 5' tall and 4' wide.
- Watering: Water plants thoroughly, letting the excess water drain through the bottom of the pot. Be sure to keep excess water out of any tray underneath the pot. Keep moist during the spring and summer, repeating twice a week through the summer. Water less in winter, allowing the soil to dry a little.
- Fertilizer: To promote more flowers and fruit, use a well-balanced fertilizer twice a month, April – October.
- Lighting: Full sun is best outside in summer. Otherwise, half a day of sun is sufficient. In the winter inside the home, bright light is sufficient.
- Blooming: Fragrance galore! In some cases, they will bloom the first season in late fall and early winter. After that bloom, they'll repeatedly blossom all year round.
- Fruiting: In some cases, the trees will produce fruit in the winter of the first season. Fruit will definitely appear in the second season. Ripening occurs in the winter months while inside the home.
- Temperature Zone: Zones 9 – 11. In pots, these are hardy down to about 40°F without damaging the plant. If you live in a climate where temperatures rarely dip below freezing, they may remain outside year round.
- Winter Season: This is when the fruit begins to ripen! Place in a brightly lit room or sunny window area and reduce watering to once a week.
- Pruning: The best time to prune is early summer during its active growth period. Pruning need not occur, but does encourage branching. New growth will flower and then fruit.
- Grooming: Cut away any yellow or brown leaves and broken stems that naturally occur. Monthly misting with a solution of soapy water will ensure glossy pest-free leaves. Mix a half teaspoon of standard liquid dish soap in a one-quart spray bottle of water. Then, shake and mist the plant profusely.
Frequently Asked Questions
Q: When will citrus trees fruit?
A: In some cases, you may get fruit the first season. Fruit will definitely appear in the second season. Ripening occurs in winter months through early summer.
Q: What pot size is sufficient?
A: Citrus trees need a 10" – 20" diameter pot to grow to full maturity. You can increase the pot size as the plant starts to grow.
Q: Can they grow inside year-round?
A: Not year-round. The only time to have them in the home is in the winter months, when the trees are fruiting. If you live in a climate where temperatures go below about 40°F, bring them inside and place them by a window. They may drop a few old leaves in the home as new ones appear. In the spring, take them back outside.
Q: Is pruning necessary?
A: No. The best time to prune is early summer during its active growth period. Pruning need not occur, but does encourage branching. New growth will flower and then fruit. Just prune above fruit or flower zone.
Q: How do I prevent drooping leaves in the summer?
A: Citrus trees need plenty of water in the summer. In pots on the deck in the hot sun, water them every day. A morning and late-afternoon watering and morning watering are often needed. This is the season when fruit is forming, so keep it adequately hydrated.
Q: Is fertilizing necessary?
A: Yes. Citrus trees respond to regular weekly feeding or bi-weekly feeding.