How to grow Grapefruit Tree

Where to plant

Plant grapefruit in full sun. Citrus tolerate light shade but crop best in full sun, and the trees grow large, so keep them at least 15 feet from other trees and well clear of buildings, septic tanks and drain fields.

Frost is the main limit. Where freezes come every few years, choose hardier citrus such as satsuma or kumquat instead. Texas A&M AgriLife notes that the length of a freeze matters more than the lowest temperature, so a few hours at 26°F does more harm than a brief dip to 24°F.

• Central and South Florida: the classic grapefruit country. Plant container trees at any time of year.
• Southern and Northern California and the Desert Southwest: plant in spring once frost has passed, in the warmest spot you have. Grapefruit needs a lot of summer heat to sweeten.
• Hawaii: grows well at low elevations.
• North Florida, the Gulf South and Texas outside the Rio Grande Valley: freezes are too frequent for grapefruit, which is why this page does not recommend it there. Grow cold-hardy citrus instead.

Choosing a variety

UF/IFAS notes that grapefruit varieties are prone to scab, greasy spot and melanose, mostly blemishes on the fruit skin. Buy a grafted tree from a licensed nursery that sells certified, disease-free citrus.

How to plant

1. Buy a certified, container-grown tree from a licensed local nursery. In quarantine areas, citrus plants must not be brought in from outside.
2. Plant at the same soil level as the tree grew in its pot. Remove some of the potting mix from the outside of the root ball so the outer roots grow out into the surrounding soil.
3. Build a ring of soil around the tree to make a watering basin that holds 5 to 10 gallons.
4. Fill the basin twice a week for the first month, then water whenever new growth wilts in the afternoon.
5. Keep grass, weeds and mulch away from the trunk. UF/IFAS advises keeping any mulch at least a foot from the trunk to prevent foot rot.

Watering and feeding

Water young trees deeply and often while they establish. Established trees in southern Texas need about 1 to 2 inches of water a week in the growing season, applied over a wide area rather than in one deep puddle, as most feeder roots are in the top foot or two of soil. Never keep the soil saturated.

Start feeding three weeks after planting. UF/IFAS suggests a balanced citrus fertilizer with micronutrients, such as one with 8 percent each of nitrogen, phosphate and potash, about every six weeks from February to October in the first year, then fewer, larger feeds as the tree grows. Spread it under the canopy and beyond, never against the trunk.

Pruning and care through the year

• Remove shoots that grow from below the graft, as they come from the rootstock.
• Mature trees need little pruning. Remove dead wood and water sprouts, and prune only to keep the tree clear of paths and buildings, as heavy pruning cuts the crop.
• Before a hard freeze, water the ground well a few days ahead, pull mulch back so the soil can store heat, and cover young trees to the ground with frost cloth or blankets.
• Check new shoots regularly for Asian citrus psyllid and report suspected citrus greening to your state department of agriculture or extension office.

Harvesting

Grapefruit ripens slowly and holds well on the tree, so you can pick over many months, roughly from November to May in Florida depending on the variety. Taste one to check: color alone is not a reliable guide. Clip or twist the fruit off with its button.

Picked fruit keeps for a few weeks in the refrigerator.

Using it

Grapefruit and grapefruit juice can change how some prescription and over-the-counter medicines work, including some statins and blood pressure drugs. The FDA advises checking the label and asking your pharmacist if you take regular medicine.