Introduced in 1984, the Rio Red grapefruit variety is a relative newcomer to the citrus scene. Derived from the Ruby Red grapefruit, Rio Red typically grows well in hot inland regions and is winter hardy in zones 10 to 12. The seedless fruit has blushed skin, attractive light-burgundy flesh and an excellent sweet-tart flavor.
Rio Red fruit is small in size, with a slightly pebbled surface. The rind frequently develops a reddish blush, especially where two fruits grow against each other. The flesh is juicy and well-pigmented, with the darkest color next to the segment membranes. Rio Red fruits mature mid to late-season. The trees grow vigorously and are relatively large in size.
Generally speaking however, late autumn is when grapefruits are ready to pick. Mature fruit may be left on the tree and, in fact, will sweeten throughout the winter. This method enables you to “store” the fruit for a longer period of time than if you picked it all at once. The downside is that storing on the tree reduces the yield the succeeding year. So, late fall into the winter or early spring is when to harvest grapefruit.
AKA Texas Red Grapefruit