sactown wrote:

What time of year is the best to prune my grapefruit tree? It is well
established and producing a lot of fruit. I am in the central valey of
California.

Prune in the spring and early summer, when frost is not expected.
Pruning encourages new growth, which is easily damaged by frost.

Also, prune only as needed. Citrus does not need pruning to
produce fruit. Thus, the purpose should be to remove deadwood,
branches that rub each other, etc. In a home garden, you may also
prune to enhance the aesthetics of the tree. Finally, for dwarf
citrus in containers, prune to keep the foliage from exceeding the
ability of restricted roots to supply water.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 19 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a)
Gardening pages at http://www.rossde.com/garden/