CITRUS

Grow your own lemons, limes, oranges and kumquats! Citrus are known for their evergreen foliage, fragrant blooms, and, of course, distinctive tangy fruits. They are members of the genus Rutaceae, the rue family, and are native to Australia and the tropics of Asia. Once citrus entered cultivation, the plants spread quickly as travel and trade expanded, flooding the Middle East and Roman empire, then onward throughout Europe. The arrival of citrus inspired the French to build special Orangeries (an “orange house”), in order to cultivate the fruits in their cooler climate. Today, there are thousands of cultivated varieties, as citrus are extremely easy to cross with other citrus. It actually leads to confusion in the taxonomic community on how to classify them, due to how intertwined citrus genetics are.

Citrus can be excellent plants for container gardening, as long as their specific conditions are met. In cold climates, they should be kept indoors in the late fall and winter months, then allowed to spend their summers outside in the sun.

LIGHT

Citrus are high light plants. When grown indoors, they need to be in south or southwest facing windows where they can receive 6+ hours of direct light. Citrus also benefit from supplementary grow lights in addition to direct light from a window. While citrus foliage can adapt to tolerate indirect light, the plant will not set flower or fruit if not provided enough consistent light, and overall the growth will stretch and slow immensely.

In the warmer months, it is recommended that citrus be grown outside. Although citrus do want to grow in full sun, they need a little bit of time to acclimate when going from indoors to outdoors, in order to prevent leaf burn. It is recommended they are put outside into full shade for about a week or so, then moved into partial shade for another week, then transitioned into full sun for the growing season.

WATERING & SOIL

Citrus are sensitive to overwatering, especially indoors. Allow your plant to dry between waterings, then fully saturate the root ball. Citrus do best in well draining soil, with lots of sand, pumice, and perlite. Oftentimes they are potted in the same substrate as cactus and succulents, which is porous and dries more quickly than other potting mediums. 

A citrus plant’s watering needs will change significantly throughout the seasons, particularly if they are put outside in the summer. For example, a plant that needs water every two weeks inside during the winter may need it every other day outside in the summer. 

TEMPERATURE 

Citrus plants do best from 55-85° F, and typically set flower when nighttime temperatures are roughly 10° F lower than daytime temperatures. They can survive short durations of lower temperatures, down to just above freezing (i.e., if you forget to bring it inside and the temp drops overnight, the plant should be able to recover if promptly brought in). Citrus can also tolerate higher temperatures, but it is important to keep up on the watering when it is in high heat. It is recommended the plant be watered deeply in the morning to help it get through any particularly hot days. In the event of consistent temperatures over 100° F, the plant can be temporarily moved to partial shade.

FERTILIZER 

Citrus tend to be heavier feeders, and prefer a slightly more acidic environment. With that in mind, they grow best when fed with balanced or slightly nitrogen rich fertilizer, supplemented occasionally with an acidic fertilizer to balance the soil. Citrus appreciate frequent fertilization from the time they bloom until their fruit is set (fruit set is the process of the flower transitioning into a berry, that will develop into a matured fruit). They do not go dormant in the colder months like many other plants, so citrus should be fed throughout the year. They will need to be fertilized often in the warmer months, possibly as often as every other week. In the winter months, when they are growing more slowly, monthly is fine. 

SPECIAL NOTES

When citrus plants are young it is recommended to prune off any fruits that the plant is producing, until it reaches about 5 years old. If the fruits are left on when the plant is too young, the plant typically begins to grow slowly, may drop leaves, and will often produce low quality fruits (until the plant is more mature). Allowing the plant to focus on root and foliar growth when young helps to ensure stronger harvests down the line, as they will have the resources to support their fruit until it matures. 

It takes anywhere from four months to a year for a typical citrus fruit to ripen. Citrus fruits do not continue to ripen when removed from the tree, so should not be removed early.