Question: We have a question about our 5- to 6-year-old navel orange tree. For the past two to three years, we left the fruit on the tree until the weatherman said freezing temperatures were coming. But with just cold nights, the fruit seems to dry out. Can we pick the fruit early and let the oranges ripen in the house?
Navel oranges are tricky in Southern Nevada. They have to be planted in just the right microclimate or they will freeze. I forwarded this question to my counterpart in Phoenix, Terry Mikel, for a response.
Navel oranges tend to be a bit persnickety, especially when they are young, no matter the cold, heat or whatever. If you are seeing lots of leaves and small branch damage, then frost will be an issue.
Freezing nights will dry out any citrus fruit. The juice inside freezes, crystals rupture the cell walls, and the juice simply drains out. The problem with citrus: If the fruits aren't ripe on the tree, they won't ripen any more off the tree.
There is another possibility. I am hoping the damage is due more to the tree being juvenile and not as much due to freezing damage. If the leaves aren't hurt by the freeze, then the fruit won't be, either. As the plant matures, there will be more "metabolism" going on and thus better fruit.
Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at firstname.lastname@example.org. Visit his blog at xtremehorticulture.blogspot.com.