Grapefruit

Citrus x paradisi · Citrus family (Rutaceae)

At a glance
Hardiness zones	9 to 11
Sun	full sun
Water	moderate
Life cycle	perennial
Frost	Tender: killed by frost
Soil pH	5.0–6.0

About Grapefruit

Grapefruit is a big evergreen citrus tree with fragrant white flowers and large yellow fruit that hold on the tree for months. It was first reported in Barbados around 1750 and reached Florida in 1823 (UF/IFAS); home types range from white 'Marsh' and 'Duncan' to deep red 'Rio Red' and 'Star Ruby'. It is less cold-hardy than oranges and grows too big for most pots, so it is best in the ground in the warmest parts of the country.

NC State lists zones 9-11. Well-hardened mature trees may get through the mid-20s F, but fruit freezes after 3 to 5 hours at 27 F (Texas A&M); in colder zones it needs a big pot and winter shelter.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

In zones 9-11 plant in full sun on the south or southeast side of the house, at least 12 feet from buildings, drives and walks, with the bud union above the soil and no basin around the trunk (Texas A&M). Budded trees should bear in the third season; pick off any fruit in the first two years (Texas A&M).

Soil

Deep, well-drained loam; heavy clay and wet soil shorten its life, and it is sensitive to salty soil (Texas A&M; NC State).

Plant in deep, well-drained soil; in good soil don't add topsoil, compost or peat to the planting hole (Texas A&M).

Feeding

First year, once growth starts: Nitrogen fertilizer such as ammonium sulfate (21-0-0). About 1 cup for the year, split into 3 or 4 feedings scattered around the tree and watered in (Texas A&M).
Second and third years: Nitrogen fertilizer such as 21-0-0. About 2 cups in year two and 3 cups in year three, split into several feedings (Texas A&M).
Bearing trees: February, May and September: Nitrogen fertilizer such as 21-0-0. About 1 cup per year of tree age, split across the three feedings; adjust the amount for fertilizers with a different nitrogen content (Texas A&M).
Potted trees: several times during the growing season: Slow-release citrus fertilizer such as 12-6-6 or 12-4-6 with iron, manganese and zinc. Follow the label for timing; citrus in pots often runs short of these micronutrients (Mississippi State).

Don't mulch against the trunk or dig a basin around a young tree; both raise the risk of foot rot, which has no cure (Texas A&M).

Harvest

Taste tells ripeness better than color: Texas fruit is legally mature by mid to late October while the peel is still green, and it gets bigger and sweeter the longer it hangs (Texas A&M). Pick as needed from late fall through May; red flesh fades over the season in 'Ruby Red' but stays red in 'Rio Red' (Texas A&M).

One crop a year, but it stores on the tree: pick as needed from late fall through May, and the fruit gets sweeter the longer it hangs (Texas A&M).

Varieties (14)

Extension sources document 14 grapefruit and grapefruit-hybrid varieties grown in U.S. home yards.

Variety	Type	Notes
Melogold	Grapefruit x pummelo hybrid	Mild, pummelo-like flavor. Sibling of Oroblanco; about a quarter larger, with a thinner peel.
Oroblanco	Grapefruit x pummelo hybrid	Sweeter and less acidic than Marsh. Always seedless; slightly larger and flatter than white grapefruit, with a thick, greenish-yellow rind; big, spreading tree.
Foster	Pink	First pink-fleshed grapefruit on record; very seedy, with a pink blush on the peel.
Thompson	Pink	Like Marsh. Also called Pink Marsh. First seedless pink grapefruit (1924); pink color fades late in the season.
Burgundy	Red	Seedless, with deep, even red flesh that holds its color late.
Flame	Red	Good sweet-acid balance; tender and juicy. Deep red flesh almost as dark as Star Ruby; smooth yellow peel with a pink blush; vigorous, large tree.
Henderson	Red	A limb sport of Ruby Red, nearly the same as Ray; redder flesh that starts fading in late February or March.
Ray Ruby	Red	Found in a Texas grove of Redblush; redder flesh and more peel blush that hold color later in the season.
Rio Red	Red	Good sweet-acid balance. Intense red flesh that does not fade; large, vigorous, productive tree. Sold as Rio Star.
Ruby Red	Red	Excellent quality. Also called Redblush. Red-pink flesh that fades after New Year's; 0 to 6 seeds; red blush on yellow peel.
Star Ruby	Red	Very sweet; the darkest red flesh. Thin, smooth peel; few or no seeds; smaller, compact tree that bears erratically and is prone to foot rot, frost and herbicide damage.
Duncan	White	Rich, balanced, high in both sugar and acid. Pale yellow flesh with 30 to 60 seeds; big, spreading tree that is hardier than Marsh. Florida's oldest grapefruit.
Garner Seedless	White	White grapefruit found near Laredo, Texas; seems hardier because it grows on its own roots.
Marsh	White	Sweet with some acid; tender and juicy, can turn bland late in the season. Light yellow flesh with few seeds; the most widely planted grapefruit worldwide. Less frost tolerant than Duncan.

Pests to watch for

Asian citrus psyllid, Citrus leafminer

Diseases and problems

Phytophthora foot rot and root rot, Citrus canker, Tristeza virus, Psorosis

In the kitchen

Mostly eaten fresh or juiced; also made into jams, jellies and baked goods, and the peel is candied (Texas A&M; NC State).

Keeping it: Grapefruit keeps best on the tree, so pick as you need it (Texas A&M). Fresh juice keeps chilled for up to a couple of weeks.

Safety: Grapefruit and its juice can change how some medicines work, raising or lowering the amount in your blood: examples include some statins, blood pressure drugs, transplant drugs, anti-anxiety drugs, heart-rhythm drugs and fexofenadine (FDA). If you take any prescription medicine, ask your doctor or pharmacist before eating grapefruit; pomelos, Seville oranges and tangelos can act the same way (FDA). The peel oils can cause skin irritation in some people (NC State).

Pets: Toxic to dogs, cats and horses (ASPCA): the fruit is edible, but the peel and plant contain essential oils and psoralens that can cause vomiting, diarrhea, depression and skin irritation.

Sources

Photo: Photo: Syrio / Wikimedia Commons, CC BY-SA 4.0 (CC BY-SA 4.0). Photo resized for the web.

Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.