No Southern California garden should be without a lemon by the back door, even if it is only in a container. What other fruit does a cook require as often and what other fruit is always there, waiting patiently on the tree until it is needed?
Lemons, like most other citrus, do not ripen their fruit all at once, nor do they drop it all at once. Fruit can hang on the tree for as long as six months without deteriorating, getting sweeter all the time.
Convinced? Then you are in luck, because this is the perfect weekend to plant any citrus in Southern California, when the soil is warm enough, but before it gets too hot. If you already have a lemon, consider any of the other citrus--grapefruit if you live in a hot interior climate, limes if you drink a lot of iced tea, tangerines if you want fruit in the fall or the dead of winter, oranges for juice (Valencia and other varieties) or peeling (Washington, Robertson or other navel varieties), or tangelos for those who like their fruit easy to peel.
Don't Stop Reading Yet
If you have all the citrus you need, don't go back to reading the rest of the paper quite yet. This weekend is also the time to fertilize citrus of all kinds--but more on that later.
Of all the citrus, lemons are the most adaptable. I know of plants that grow in shade and bear fruit (even one that grows in the shade of a live oak!) and plants that have lived in a container for 10 or more years, bearing fruit the whole time.
The ideal, of course, (and essential for other citrus), is a sunny, warm spot in the garden, though lemons need the least heat of any citrus.
If you are going to try them in a container, get a large one, at least 18 inches across. Cover the drainage holes in the bottom with squares of window screen (to keep out slugs, keep in soil) and use any good commercial potting soil. Be sure to buy plants that have been grown in a container. Don't buy field grown plants that have a heavy natural soil around their roots (although these are seldom available anymore).
Look for dwarf varieties. These are grafted on a dwarfing rootstock and will only grow about half as large as their standard counterparts--oranges, grapefruits and lemons grow to about 8 feet; tangerines and tangelos to about 6 feet. In a container, they will stay even smaller.
Lemons to Look for:
Lemon varieties to look for are the market lemon, named Eureka, which bears year-round; Improved Meyer, which is not as acid, round, thin-skinned and a natural dwarf; and Lisbon, which is thorny with fruit that comes mostly in the fall.
If you seek the unusual, there is also the King Kong of lemons, named Ponderosa, with fruit that can weigh two pounds, though most of that is the weight of its thick skin.
And there is a new variegated lemon, with leaves (and occasional fruit) striped cream and green. It is very ornamental and like most citrus, can be a handsome landscape plant as well as a fruit tree if you preserve the lower branches.
In the garden, lemons and other citrus should be planted in a generous hole, even if it comes in one of those tall, skinny containers. Add some amendment to the backfill and always add some fertilizer and some extra iron in the form of iron sulfate or iron chelate (both available at nurseries). Citrus often get yellow leaves (though the veins remain green), caused by a lack of iron.
Watering will be the most important part of citrus culture--and where many go wrong. Too much water (or fertilizer) can cause fruit drop and splitting, although so can the weather. After planting, for the first few months of summer, citrus should be thoroughly watered once or twice a week. Mound up a watering basin wider than the tree and be sure to fill it with at least three inches of water.
How Often to Water
For the remainder of the tree's first year, it should be watered every week to 10 days. Water every two weeks during the following two years. Mature trees should be irrigated every two to six weeks depending on season and soil. In a container, water every few days.
Citrus should be fertilized three times a year. Once now (but only if the tree has been in the ground for at least a few months), once in August and once in March. Use a fertilizer that is mostly nitrogen (the first number in the formula found on the back of a package, the 20 in 20-5-5). Scatter it evenly under the canopy of the tree and water it in with a sprinkler. Use about half the amount suggested on the package.
And, if you live in a hot area, be sure to protect trunks that are baking in the sun with a wrap of paper or a coat of white latex paint. Otherwise they will sunburn like a lifeguard's nose.