There's an honorary day, week or month for everything, including grapefruit! February is National Grapefruit Month, so let's discuss grapefruit from the gardener's perspective.
(Editor's Note: This article was originally published on February 6, 2009. Your comments ar welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Citrus x paradisi, the forbidden fruit, shaddock, pamplemousse ... my, doesn't that sound rare and exotic, or really weird? But all those terms refer to the common grapefruit now sold in most grocery stores year round. National Grapefruit Month was probably established to promote consuming the fruit. However, since you are reading in Dave's Garden, this will be a brief introduction to home cultivation of Citrus x paradisi. Then you can decide whether (or not) to grow a grapefruit to supply your family with fruit, to decorate your deck, or just as a fun seed-growing experiment.
Grapefruit for the home garden
To have your own grapefruit orchard, or even a single tree in the ground, you'll need to live in a subtropical or tropical area. Unlike cherries or apples, grapefruit trees can only withstand the briefest and rarest of frosts. In the United States, that pretty much means you must live in Arizona, Texas, California or Florida to grow a grapefruit, and not all parts of those states are good grapefruit zones. Further, cooler parts of those areas will produce more acidic, slower ripening fruit. Grapefruit just doesn't like cold weather. One grapefruit tree should give enough fruit for a family, and usually does not need a partner for pollination.
Grapefruit can grow successfully on a variety of soil types, as long as drainage is good, and likes a nearly neutral soil pH. A grapefruit tree is a small to medium tree with glossy green oval leaves and some thorns. The flowers are white and fragrant and the fruit grows in clusters; that clustering is what put the "grape" in the name grapefruit. For delicious fruit, buy a grafted plant from a reputable grower. (Like many citrus, grapefruit won't grow true from seed.) Expect regular annual harvests within a few years of planting. Fruits will be mature somewehere from 7 to 13 months after flowering. Once ripe, the fruit can be left on the tree and harvested over a period of months without losing quality. Refer to the links in "Resources" below for more details on growing grapefruits.
Grapefruit as a large potted plant
Gardeners whose properties experience yearly frost might grow grapefruit as a large potted plant. Rodale's Encyclopedia of Organic Gardening says it can be done. Understand, however, that this tree needs warmth and sunshine to create huge tasty fruits, and a far-northern indoor gardener may be hard pressed to provide enough of either. For tasty fruit, you must buy a grafted tree. Rodale's suggests 'Oroblanco' as a good variety for pot culture, but a reputable nursery can guide you in your selection and may offer other cultivars as well. Use a good potting mix and fertilizer with micronutrients. Pot the tree up (into larger pots) as it grows and move it to a sheltered, sunny outside spot in warm weather for maximum growth. You'll have to limit the pot size, of course, to what you can physically move inside during cold weather and outside in balmy months. The nursery-grown plant may take a couple of years to be mature enough for flowers and fruit.
Grapefruit as a novel houseplant
If you enjoy houseplants and are willing to forego fruit, you can grow grapefruit trees from grocery store fruit seeds. Some grapefruit are seedless, but most have seeds, and they can number in the dozens per fruit. Plant several seeds in a small pot of moist potting soil. In about three weeks, you'll probably see a few green sprouts emerge. Three to five plants will be happy together and provide a bushier houseplant. Baby grapefruit trees have pretty, shiny green leaves and stems. Use a good soil and fertilizer, replant the grapefruits when they seem too big for their current container, and keep them in a bright location. The plant may show you its white, very fragrant flowers after several years, along with some thorns.
How will you celebrate National Grapefruit Month- with a trowel or a teaspoon in hand? Plant or just eat grapefruit; the informative links in the Resources section below can help you decide.
Shaddock is an old name for grapefruit. Some sources say grapefruit originated in a natural cross-pollination between two other citrus, on the island of Barbados. (Hmm, perhaps Dave can send me there to do some more in-depth research.)
The pomelo or Chinese grapefruit is one of the parents of modern grapefruit. Pomelo is much larger than grapefruit, with a thick rind, but is said to be sweeter than grapefruit.
The United States produced 1,580,000 tonnes, (that's about 1,738,000 tons,) of grapefruit in 2007. The U.S. exported more grapefruit than any other country in 2004, to the tune of $227 million. In that same year, Japan spent about that much money importing grapefruit.(FAOSTAT)
Red grapefruit is the state fruit of Texas.
Mature fruit can be left on the tree for several months without spoiling. Pick the biggest of the fruits. Determining when to harvest will be a challenge, as the fruit color is completely unreliable in telling you when the flesh is juicy and sweet.
Ripe grapefruit stays fresh and juicy for 2-3 weeks in the homerefrigerator.
Substances in grapefruit juice can affect how certain medications work. Here's a link for more information on that issue, and a list of affected medicines.
Morton, J. 1987. Grapefruit. p. 152-158. In: Fruits of warm climates. Julia F. Morton, Miami, FL - Provided by NewCROPTM the New Crop Resource Online Program "The Web site of the Center for New Crops & Plant Products, at Purdue University. NewCROP provides windows to new and specialty crop profiles."
I grew up playing in the Maryland woods, and would still do it often if life allowed! Graduate of University of Maryland, my degree is in Agriculture. Gardens and natural areas give me endless opportunity for learning and wonder. Naturally (pun intended) my garden style leans towards the casual, and my cultural methods towards organic. I like to try new plants, and have "some of everything" in my indoor and outdoor gardens. Thanks go to my parents for passing along their love of gardening and nature, and my husband and kids for being patient when I get lost in the garden.