Will Grapefruit Freeze on the Tree?
- Grapefruit trees are most widely grown where the winters get no colder than 25 degrees Fahrenheit, which correlates to U.S. Department of Agriculture plant hardiness zones 9b and warmer. Some gardeners choose to grow grapefruits even in zone 9a, where winters get as cold as 20 F. In such regions, it's a game of chance and luck to hopefully grow the trees during a span of years with warmer than average winters. If the tree is small in size, you can temporarily throw a blanket or frost cloth over the leafy canopy to shield it from cold.
Effects of Freeze
- If the subfreezing temperatures drop below 25 F or endure for a long time, even the fruits held well above the ground can freeze. Typically, the coldest air settles at the ground. The grapefruit tree's evergreen leaves help insulate fruits and their elevation above the ground keeps them a bit warmer. The rind of the fruit can buffer some cold, but the juicy flesh readily freezes once cold penetrates through the rind. After the freeze event, one to two days later, any partially frozen fruits will feel unusually soft when squeezed. Fruits not harmed are smooth and firm and can remain on the tree to further sweeten.
- According to the University of Florida, freeze damage on citrus fruits begins from the stem end of the fruit and progresses downward. The subfreezing temperatures cause the water-based fluids in the rind or flesh to rupture and then tissues fully dry. Besides feeling soft to the touch, the rind may blemish and turn tan days later. Eventually, the freeze-damaged grapefruit rots around the stem and the softened fruit plummets to the ground.
What to Do With Frozen Grapefruits
- Frozen grapefruits develop softness and other telltale signs within 24 to 48 hours. There is nothing that can be done to reverse the damage or make the tree heal and retain the harmed fruits. The best option is to harvest frozen fruits and squeeze them for juice. Depending on the extent of grapefruit ripeness, the juice may be quite sour if the fruits were immature when frozen.