Like other citrus fruits, lemons are technically berries that have a thick rind and a very juicy interior divided into segments by septa (“dividers”) called the “hesperidium”.1 (Seen here in the “whiter” middle part of the cross section of a lemon –
Lemons are yellow most of the time although they can be green or greenish-yellow depending on the variety. They are citrus fruits that are shaped like footballs and are mostly used for their sour, tangy juice although they can also be consumed raw. They are occasionally used as garnishes for drinks and can be used in cooking to add zest to a dish.
Lemons and other fruits of citrus trees are considered “Hesperidia”. Hesperidia are a type of modified berry with a leathery rind. ³¹
The Peel/Rind (outside layer)
Epidermis – thin outer layer of cells
Exocarp/Flavedo – layer of essential oil-containing sacs
Mesocarp/Albedo – white pith, bitter. This extends into the middle of the fruit, segmenting the sections of pulp within.
Pulp – segments of juice sacs which contain the desired “fruit” part of the fruit and the seeds
Columnella – apparently the middle column that centrally separates the pulp sections³²
Lemons and all other citrus trees are related to a common wild ancestor from around 8 million years ago. This papeda-like fruit is an ancient wild variety of citrus fruit. This great grandfather of the lemon is sour, bitter, unpalateable, and uncultivated. As the years went on, other species of citrus branched off from the papeda into other citrus varieties, first naturally and then through human intervention. It is believed that the lemon was crossbred between a natural citrus fruit called the “citron” and a semidomesticated variety of bitter orange.²⁰Bitter oranges seem to be a hybrid of the Chinese mandarin and are first recorded in Islamic Spain around 1000AD.
Lemon trees, like many other citrus trees, are native to north-western India although they are now grown in many temperate and sub-arid regions throughout the world. Lemons were introduced to southern Italy around 200 AD and have been harvested in Egypt and Iran since 700 AD. But it widespread popularity in the Mediterranean seems to occur after 1000AD. Likely pushed by Arab traders.They were initially used as an ornamental plant until about the 10th century and came into full culinary use in 15th century Europe.9
As their forebears, the citron and bitter orange, are both edible it’s probably safe to say lemons were eaten even in their ornamental phase.
Christopher Columbus brought lemon seeds to the New World in 1492 where he planted them in Hipaniola in 1493. From there, Spaniard explorers planted lemons in Florida and California.2 In the 1890s when Florida was undergoing a freeze and the lemon production there was halted, California became the leading lemon industry, and hasn’t looked back since.
In the 1890s, Florida was the lead citrus-producing region with around 3 million trees in cultivation. Then in December of 1894 a bad freeze hit the state, destroying that year’s crop and damaging trees. The following February of 1895 another even worse freeze hit the region, destroying many of the already weakened trees. This Great Freeze of 1894-95 turned all of Florida’s lemons into sherbert, and set their citrus industry back 10 years.
In the meantime, California also had a decent lemon industry with 62,000 trees in cultivation. While Florida was recovering, California stepped into the gap and made up the shortage, rapidly expanding its lemon groves to 800,000 trees by 1901. From there, California continued to grow its acreage and maintain its dominant lemon production positon.²²’²³
The name “lemon” can be traced back to the Persian word “limun”. It was first donned “lemon” in the late 14th to 15th centuries.9
The word lemon was possibly initially inspired by a Malaysian word “limaw” meaning a lime, lemon, or tart citrus fruit. Southeast Asia is a natural environment for citruses, suggesting lemons or similar fruits were familiar to its inhabitants. Persians picked it up via India, calling it “limun”. Arab traders called in “laimun” which was picked up by romance language speakers as “limon”.²⁴
Lemons are full of vitamin C. When traveling on ships for countless days and nights, sailors and pirates would contract scurvy – a vitamin C deficiency – due to not eating many fruits and vegetables during their time at sea. Therefore, many ship captains and pirates would stock their ships with lemons and other citrus fruits such as oranges and grapefruits to make sure they didn’t contract scurvy while sailing.2 In addition to having a significant amount of vitamin C, lemons are also a good source of dietary fiber.3
Lemons also have an appreciable amount of potassium. Gram for gram, lemon juice has a third of the potassium that bananas have. (Lemon: 103mg/100g – Banana: 358mg/100g)¹⁷’¹⁸
Lemons are most commonly consumed raw by peeling, separating into quarters, and eating. Lemons can also be put into water, tea, or other beverages to add some sour flavor to the drink. In addition, the juice from lemons can be used a lot in cooking, baking, and other preparation of dishes. The peels can be shaved to add a zesty flavor to a savory meat dish. Traditionally, lemons have been used in soups and stews to add a bit of twang to the soup broth, mostly in chicken or mutton (lamb) dishes.
Limoncello is also a popular way to consume lemons. Believed to have originated in Siciliy around 1900, limoncello is a sweet liquor infused with lemon peels to make a citrusy digestif. If you’re juicing lemons for something, limoncello is a wonderful way to utilize the zest of the peel.
In addition to being consumed as fruit, lemons are also commonly processed into other foods or consumer goods. There is a large commercial industry in both California and Argentina dedicated to processing lemons into juice and essential oil.
Lemons contain an aromatic oil that, when pressed from the peel of the fruit, results in a concentrated flavor and fragrance ingredient. Lemon essential oil is used heavily in the beverage industry as a flavor component in some of the market’s most popular sodas. It’s also the basis of many candy, sherbert, and confectionery flavorings.
Lemon essential oil is also used commonly in fragrances, to give perfumes a fresh, citrusy character. Processed lemon oil also functions as an excellent surface cleaner and degreaser for cleaning products.
Lemons that have had their essential oils extracted go on to be pressed for their juice, which is used in lemonade concentrates and the bottles of lemon juice available in grocery stores.
California is a significant global producer of lemon essential oil along with Argentina and Italy. The oil produced there is prized for its sweet, juicy, almost candy-like aroma.
Lemons can also be used to clean ovens. Squeeze lemons into an oven-safe bowl of water. Place in oven and heat. Once boiling turn off heat and let the steam work. After steam settles, wipe off grime from inside oven.
There are countless varieties of lemons grown throughout the world. In California, the most common lemon tree is the Eureka lemon tree. These lemons are what you would see in the produce section of your local grocery store. Other types of lemon trees grown in California are the Lisbon lemon tree, the Meyer lemon tree, and the Verna lemon tree – although the Verna lemon is more of an ornamental variety of lemon tree, although it can be used in culinary and in medications.
The Eureka lemons have a more sour, tangy flavor while the Meyer lemons are more fragrant and slightly sweeter. Visually, Meyer lemons are a brighter yellow color and a little smoother than Eureka lemons.
The most common variety of lemons grown in California are Eurekas and Lisbons.²⁶
In other parts of the world, Greek Citron lemons, Bush lemons, Volkamer lemons, and Babboon lemons are grown. Each of these varieties either have a different flavor or sweetness to them or they are seedless variants.
Most of the lemons that are imported into the United States come from Argentina, Mexico and Chile. However, India still remains the largest producer of lemons in the world, with approximately 17% of the world’s lemons coming from India.4
In California, since the early 19th century, the yield per acre of lemons has grown substantially from 100 boxes of lemons per acre to 400 boxes per acre.5 In the 2019-2020 growing season, total US citrus acreage was 668,100 acres while 57,300 of those acres were lemon trees. 50,000 of those acres were grown in California alone with the other 7,300 being grown in Arizona.8 Approximately 20-25% of California’s citrus fruits (including lemons) are exported with Canada being the number one market.10
In 2020, California grew 93% of the US’s lemons.²⁸ In 2020, California grew 53% of the US’s citrus. Florida is the other major citrus grower with Texas and Arizona as distant seconds.²⁷
Lemons grow best in hardiness zones 9-11 (Florida, Arizona, southern California). These areas do not drop below 25 degrees Fahrenheit and do not rise above 100 degrees Fahrenheit during much of the growing season. In addition, hardiness zones 9-11 are known for their sandy soils which allows for more proper infiltration of water through the soil to keep the lemon trees from retaining too much moisture in their root system.
Close to 90% of California’s citrus acreage is located in the five Southern California counties: Fresno, Kern, Tulare, Ventura, and Riverside. Orange County, which once was a vibrant citrus producing county in California, reported only 71 acres of citrus fruit production in 2013.5
The major lemon acreage in California is in the Coastal Region, Desert Region, and Central Valley.²⁶
Because lemons need proper drainage so the roots cannot get overly wet, quick draining sandy soils are the best soil type for producing lemons.
Fertilizer is one of the primary expenses and inputs for a lemon farmer. Compared to other citrus trees, lemons need double the amount of fertilizer to grow effectively.11 Lemon trees need a slightly nitrogen-rich blend of fertilizer to produce an abundant crop. Fertilizing every 4 to 6 weeks from February to August will assist in producing a large lemon crop.
It is important to water lemon trees once weekly or bi-weekly depending on the climate of the region that they are planted in. They typically need an inch or two of water applied once or twice weekly12 and approximately 60 inches of water per year.13 The easiest way to know if it is time to water a lemon tree is to check the top 2 inches of soil; if the soil is dry, it is time to water. But it is important not to give these trees too much water as the tree root zone can become too wet and not produce efficient fruit. Having proper irrigation setup will limit the amount of water waste. It takes approximately 77 gallons of water to produce 1 pound of lemons.6
Citrus fruit orchards in California require 4.23 acre-feet or water on average, or 1,378,349 gallons per acre. A slightly high figure, more than vineyards and other fruit trees but less than pastureland and alfalfa.²⁵
Temperature & Sun
For best production, lemon trees need 6-8 hours of direct sunlight each day.
Lemon trees prefer a temperature range of 70-100 degrees Fahrenheit, so the changing climate can have an effect on when to plant these trees and how well they will produce fruit from year to year.
The initial season of harvest for lemons is late winter, early spring but this depends on when you plant the tree. If you plant your lemon tree in late February, the lemon tree will produce fruit earlier than if you plant in early March. However, it is important to consider that you do not want to plant lemon trees when it is 25 degrees Farenheit or less outside, so when lemon trees are planted will depend on the hardiness zone of the area they are being planted in.
After the initial harvest season, many varieties of lemon trees (including California’s Eureka and Lisbon varieties) produce fruit year-round with winter being the primary season of growth for the citrus fruit. Many lemon trees grow 6-12 inches each year, reaching 20+ feet over time depending on the variety of lemon tree planted. It could take a lemon tree up to 25 years to reach it’s full height. It could take a year for lemon fruits to start showing up and then another 6 to 9 months for the lemons to be fully ripe and ready for consumption.16
Lemon trees usually produce fruit about 1 to 3 years after planting, depending on variety, and most varieties can grow year-round. Once fruit is producing, it can take up to 6 months for a lemon to ripen and mature on the tree. Lemon trees are able to produce fruit for about 50 years after they start to fruit. The farmer says a lemon tree does not produce a full crop until 5 years old.²⁶
The cycle for an individual lemon tree during the year is to bloom, set fruit, then be harvested.²⁶ Flowering of trees generally occurs during the spring. Fruit develops over the summer, but can take anywhere from 4-12 months to become ripe. Because of this extended ripening there can be ripe fruits and flowers on the tree at the same time. Though lemon trees are deciduous, they do not regularly ose their leaves. Leaf fall can happen if there is a cold shock.²⁹
Plant lemon tree sprigs in late February to early March to avoid harsh winter or harsh summer temperatures. If you are starting a farm with the most common lemon tree, the Eureka, you need to plant each tree approximately 15-20 feet apart. The larger the distance between trees, the larger the fruit on the tree will grow. Sprigs are grafted from the branches of other lemon trees.
Pruning of lemon trees is important to maintain efficient fruit production. You want the lemon tree to maintain it’s shape. Do not allow branches to outgrow the rest of the tree and do not allow branches to turn back and grow toward the trunk of the tree. You may have to prune daily to assure that the tree stays within it’s shape.
All lemon trees are grafted at the nursery. The scion, or fruit-producing part, is grafted onto a root stock that is planted in the ground. The scion is selected for the fruit it produces. The rootstock is selected for hardiness.²⁶ The rootstock comes from a different lemon cultivar that is hardy. Nurseries seem to grow the rootstock from seedlings but can also propagate them via cuttings from an existing tree. Scions are grafted onto the rootstocks at the nurseries and farmers get the seedlings from those nurseries.³⁰
During the year, orchards are maintained by: pruning, irrigating, pest control, fungicide applications, growth regulator applications, and weed control.²⁶
Lemons can be harvested all year long but the winter and early spring are the most common seasons. After the winter/early spring season, some varieties of lemons can produce fruit year round. They are best picked by hand so that the harvester can get a feel for how ripe they may be. The color of the lemon should be yellow or yellow-green on the outside when ripe. Ripe lemons should be heavy for their size, give slightly when squeezed, and have a nice fragrance. Avoid moldy lemons or lemons that are too soft.14
Lemon trees can be prickly and cut into your skin so it is best to hold the branch back with one hand and then pull the lemon off the branch with the other hand, making sure you don’t pull too much of the lemon tree branch off with the fruit.
Lemons are harvested, sometimes while still unripe, and sent directly to the grocery store for purchase. But lemons prefer to ripen on the tree so it is best to pick them when they are at peak ripeness rather than earlier.
Lemons are harvested at different times depending on where they are grown in California. In teh Coastal Region D2 they are picked year-round. In the Desert Region D3 they are picked from August/September through January. In the Central Valley Region D1 they are picked from October through June.²⁶
Lemon fruits can be stored in a basement or cellar just as apples and oranges are stored but they are best stored in a refrigerator where they can retain their moisture. Here, they can be kept for a few months rather than a few weeks. If you are harvesting lemons for their juice, you can squeeze the lemon to harvest the juice into containers and then freeze the juice to keep for quite a few months.
Although lemon trees have some pests and disease that can threaten the production of the fruit, many organic, natural solutions work well and produce a more sustainable crop. A mixture of hydrogen peroxide, baking soda, olive-oil based soap, and water can keep pests away from lemon trees while a baking soda, canola oil, and water mixture can prevent fungal infections on the foliage of the tree.15
When riddled by disease, simply remove the infected area from the tree, whether it is the bark, leaves, or fruit and make sure all trace of the disease is gone. In time, the lemon tree will begin to produce more efficiently.
Lemons, Oranges, Limes, and other citrus trees have also been subject to an emerging threat from invasive insects. The Asian Citrus Psyllid is an invasive species that carries a bacterium that causes citrus greening disease. Citrus greening disease destroys a tree’s fruit and eventually kills it. The best practice is do avoid infection by not moving citrus trees or foliage.¹⁹
Citrus greening is a big problem for the citrus industry, but California has been widely spared so far. Still, CA citrus growers monitor it closely.²⁶
Because lemons are some of the earliest fruits established in the New World, lemons farmers have come a very long way in establishing a sustainable lemon crop. There is no significant damage to the air, water, land, soil, etc when growing a lemons. As mentioned previously, lemons do need fertilizer to grow effectively but the fertilizer can come in the form of chicken or cattle manures, compost, or grass/leaf clippings.
Since lemons do not have many pest or disease threats, it is simple to treat them by removing the areas of disease or spraying an organic mixture mentioned above to keep the lemons organic, without any chemical pesticides or fertilizers necessary.
The Future of Lemon Farming
Researchers at the University of Florida Institute of Food and Agricultural Sciences are developing a smart tree-crop sprayer. This sprayer will allow farmers to target trees and reduce chemical usage by 30% by automatically detecting citrus trees and calculating their height, leaf density, and fruit count allowing only the appropriate amount of chemicals to be sprayed on the trees.7
Lemons are used in a variety of ways and are one of the more sustainable fruits grown in the state of California. With California being far and away the largest producer of lemons in the United States, it is simple to find a local farmer to provide your next batch of lemons!
- Berry (Botany)
- Lemon Fact Sheet
- Health Benefits of Lemon
- Why are lemon prices so high in India, the largest producer of lemons in the world?
- Citrus Production in California
- Lemon Benefits and Side Effects
- UF developing smart technology to help citrus farmers
- Citrus Fruits 2020 Summary
- Lemon History
- Lemon’s grow California’s export market.
- Fertilizing Lemon Trees
- Water requirement for a lemon tree.
- Irrigating Citrus Trees
- All about lemons
- Homemade lemon tree fungal & pest spray
- Lemon tree timeline: How long does it take lemons to grow?
- USDA Lemon Facts
- USDA Banana Facts
- USDA Citrus Psyllids
- Citrus Genetics
- Two Historical Recipes for Preserved Lemons
- Citrus in California
- The Great Florida Citrus Freeze
- Etymology Online Lemon
- Press Democrat Article on Water Usage
- Lemon Farmer Interview
- USDA Citrus figures
- Farm Together Citrus Figures
- Homeguides Lemon Guide
- Citrus Nursery Production Guide
- Hesperidium Wikipedia Page
- Hesperidium Paper Abstracts