Martin Lowe Jr., age 10, of Nogales, Ariz., for his question:
HOW ARE LEMONS HARVESTED?
Lemon is a citrus fruit that is native to southeastern Asia, but it is now grown commercially in the countries around the Mediterranean area and in Southern California and Arizona. Lemons must be picked by hand when they are harvested.
Pickers use a metal ring to determine the size of the fruit. They pass each fruit through the metal ring. They pick only those that are two and a quarter inches or more in diameter. Smaller fruits are left on the tree until they grow larger.
Lemons differ from all other citrus fruits in that they become more edible after they are picked. Workers pick the fruit when they are still green. The lemons ripen in special curing rooms where the temperature is kept at 56 to 60 degrees Fahrenheit, and the humidity is at 85 to 90 percent.
Botanists call the lemon fruit a hesperidium, which is a special kind of many celled berry, typical of the citrus family. It is covered with a yellow skin dotted with tiny glands that look like pores. These glands contain oils.
A thick, spongy membrane lines the skin. It encloses six to eight segments that contain the pulp, juice and seeds. Lemons have only a few small seeds and often none at all.
Lemon juice is rich in Vitamin A, B and C and in mineral salts. The juice is usually quite tart but some kinds of lemons have sweet juice.
Lemon trees bloom and produce fruit almost continuously in the right climate and with proper care. They bear most fruit during winter and early summer.
The leading lemon growing country in the world is Italy, followed closely by the United States. Argentina rates third followed by Turkey, Greece, Spain, Lebanon and Chile.
Growers plant the trees in good, well drained soil. They do not need much water. Lemon trees that get too much water grow quickly but produce less fruit. Over irrigation may also kill the trees.
Growers raise lemon trees by grafting buds to seedling root stocks of other kinds of citrus fruits. The sweet orange rootstock is used most commonly in Southern California.
Some growers use the grapefruit or the rough lemon, a relative of the lemon, as a rootstock. The fruit of the rough lemon has no value, but the rootstock is hardy.
Almost all California lemon growers heat their orchards with fans because the trees do not resist frost well. Sudden heat and wind also affect both trees and fruit, and many growers protect the trees with windbreaks.
Today many lemons are made into frozen concentrates. One important lemon byproduct is citric acid, a white crystalline powder. It is used as a base for carbonated beverages, as a laxative in medicines and as a flavoring in baked goods. Lemons are also extensively used for cooking, candies and toilet preparations. The oil is used for flavoring and for making perfumes.