Lemons

 By Kim Willis These articles are copyrighted and may not be copied or used without the permission of the author.

If you enjoy lemons it is possible for homeowners in the southern reaches of the US to grow this lovely tree in the yard.  And for everyone else, the lemon makes a wonderful potted plant and can even bloom and produce lemons for you indoors.  I have had a lemon tree for many years and for the last few years I have got a few small lemons each winter from it.

History of Lemons

 No one knows where the first lemon tree grew, somewhere warm, possibly northwest India. They were known to be cultivated in southern Italy, the Mideast and China in ancient times.  Sailors and other travelers frequently carried lemons with them to prevent scurvy.  Columbus carried lemons with him when he landed in the New World in 1492.

Lemons were grown as a crop in California as early as 1751 and in Florida in the early 1800’s.  While lemons are still grown as a crop in those states and in Arizona, the biggest growers of lemons are the Mediterranean areas of Italy, Spain, Greece, Cyprus and Turkey.  Southern Mexico and other Latin American countries also produce lemons.

How Lemons Grow

The true wild lemons are small trees rarely more than 20 feet high.  The branches and leaves are alternate on the tree. Lemon trees have sharp thorns, particularly when young.  Some thorn-less or nearly thorn-less varieties have been bred however. Lemon leaves are thick, shaped like a long oval with fine serrations on the edge and small “wings” on the leaf stems.  They emerge reddish in tint and turn dark green on top and lighter green below.  The tree is evergreen, retaining its leaves year-round.  

Lemons flower sporadically throughout the year, although commercial varieties are bred to have larger crops at various times of the year.  The lemon flowers are small and white; they have a pleasant fragrance like orange blossoms, although not as strong.  The lemon fruit varies by variety but is generally some shade of yellow, although some lemons have green or white stripes.   The fruit is oval with a characteristic nipple on one end and numerous oil glands on the thick skin.

Lemon fruit may be left to ripen on the tree and will remain edible on the tree for several weeks.  Commercial growers pick lemons before they are ripe and “cure” them before they are sold.

Growing Lemons at Home

Lemons are very susceptible to frost and will survive outdoor planting only in areas that do not drop below 30 degrees. They can be covered for a few nights if temperatures get low but won’t survive a long cold period.  Zones 9 and above are probably the limit of hardiness for outdoor planting but some people have had success with the hardiest varieties in Zone 8 with some protection.

Many lemons that are sold are grafted on to rootstock from oranges or other citrus.  The varieties that grow best in your area will differ considerably from what will grow in other areas.  If you are in a citrus growing county consult with your county Extension office as to what variety of lemon will grow best in your area.

The lemons that are most often planted in yards are probably the Meyer Lemon and Ponderosa Lemon.  Both are not true lemons but are hybrids between lemons and mandarin oranges.  The fruits taste and look like lemons although they are not as acidic as true lemons.  These are the plants sold most often for growing as potted plants too.

Outside lemons prefer full sun, well-drained soil, and protection from strong winds.  They do well in courtyards and against the south wall of homes.  Lemons like fertile soil with plenty of organic matter, preferring a slightly acidic to neutral ph. 

Plant your lemon tree at the same level it was growing in the pot or nursery.  After planting, sprinkle slow release fertilizer, about a cup per tree, on the top of the soil around the tree and water well.  Do not put the fertilizer in the hole as you plant.  In areas where citrus is grown special citrus fertilizers are generally sold in garden stores. Feed lemons about three times a year, evenly spaced between March 1 and November 1.

Water your lemon tree if it gets very dry, although lemons tolerate some drought.  Deep watering several times a month is preferable to many small amounts of water, as a tree might get in an irrigated lawn.  Frequent watering where water gets on the trunk makes the lemon tree susceptible to rot diseases.  Also keep mulch from touching the trunk of the tree.

Lemon trees produce a lot of water sprouts, tiny shoots that grow on the trunk. These should be removed as soon as they appear.  You can prune the tree to keep it smaller or to shape it but avoid pruning during the winter months.  If your tree has thorns, you can clip the points off without doing any harm.  Remember when you prune you may be removing flower buds.

Growing Lemons in Pots

The Meyer and Ponderosa lemon are often sold as house and patio plants and specialty catalogs may carry some other cultivars suitable for indoor growing. Buying a plant is preferable to starting a lemon from seed from a grocery store lemon because those lemons may not be suitable for pot culture or your growing zone. 

In the south where the cold period is short, simply move the pot inside by a sunny window for a few weeks.  In the north, where cold periods are much longer, you will probably need to provide supplemental light from a grow light for several hours a day (or all day).

I think potted lemons do best if they can be moved outside for the summer.  That’s when they are most likely to bloom. Don’t put them in full sun immediately, put the potted lemon in a partly shaded spot and move it into full sun after 2 weeks so that it adjusts without burning the foliage. Lemon trees should be moved inside before temperatures fall below 40 degrees.  They prefer an indoor temperature of 65-75 degrees. 

The pot for your lemon must drain well.  Outside on the patio it should be elevated a few inches, so water drains out quickly.  Use a light, all-purpose potting soil in the pots.  Do not start the plant in too large a pot. A 6-8-inch pot is good for a seedling tree.  As the tree grows move the pot size up by a few inches a year.  

Yellowing or pale green leaves generally mean the plant needs fertilization. If you can find citrus fertilizer, use that at half the strength recommended for outside plants. Most citrus fertilizers are acidic, an acidic fertilizer for blueberries can be used. Or you can just use a houseplant fertilizer for blooming plants. Water the tree when the soil feels dry.  Do not over water potted lemons, but they should never get to the point of wilting.

Indoors lemons are susceptible to scale and spider mites.  Spider mites can be treated by raising humidity around the plant and frequently misting.  Putting the whole plant in a warm shower is also helpful. Once the tree moves outside spider mites usually disappear.  Don’t use pesticides for spider mite treatment unless the label specifies spider mites as an insect it controls.

Scale looks like brown bumps on leaves, stems and trunks.  There may be a sticky “honeydew” on leaves and near by objects.  If the tree is small enough you can go over every branch and stem and simply scrape off the scales with your fingernail or a wet cloth.  Larger trees and extreme cases of scale will need to be treated with a systemic pesticide, which means you will not be able to eat any fruit within the time frame listed on the label.

Keep your potted lemon pruned so that it remains manageable.  Even small plants can bear fruit in pots.  The lemon is self-pollinating and doesn’t need another lemon to bear fruit.  Even if the lemon doesn’t give you fruit it makes an attractive houseplant.

Harvesting

Harvest a lemon for use whenever it feels plump and looks yellow.  They will hold for a long time on the tree if you don’t need them all at once. Lemons can be canned or juiced and the juice frozen.  Refrigerate ripe fruits for longer fresh storage.

Don’t expect a large harvest from plants kept indoors, a few lemons a year are average.  Those lemon fruits are usually smaller than lemons grown outside.