Grapefruit trees provide a touch of shade, color and a harvest of fresh fruit to a garden. At one point in time, they were called the "forbidden fruit" and are thought to be from the Caribbean originally, according to Texas A&M University Extension. They grow best in subtropical climates and can reach over 30 feet tall. There are important things to keep in mind when caring for a grapefruit tree to ensure that you harvest plenty of the juicy, delicious fruit.
Adjust your watering schedule when the temperatures warm up. Water deeply from April to July , as this is the time where the weather is usually the hottest in most regions, and when the tree needs extra watering to fruit. Winter watering schedules should be adjusted to about half the amount/frequency of summer schedules.
For citrus trees such as grapefruit, good weed control is key for the maturity and healthy growth of the tree. Get rid of all the lawn grass and weeds within 4 feet of the trunk of the tree. Once your grapefruit tree is full grown, you may want to extend this area much further outwards from the trunk. You can eliminate weeds manually by hand or with a hoe; or you can use mulch, keeping at least 1 foot of bare ground between the mulch and the trunk to prevent root rot (which is especially a danger to young grapefruit trees). Use herbicides if desired for excellent control, either a post or pre-emergent herbicide.
Protecting The Trees
Grapefruit trees commonly grow in areas where they are susceptible to freezing, since they have the least cold-tolerance of any citrus tree. Constant exposure to cold weather or very low temperatures will kill a grapefruit tree or prevent it from growing any more. In cold temperatures, remove the mulch before-hand, then deeply water the tree for several days before a hard freeze is expected. This is because the ground will absorb more heat this way and than release it at night during colder times. Cover the top of the grapefruit tree with plastic sheeting or a large blanket to insulate the tree. If desired, provide additional heat with a small electric heater or lamp.