I received answers from you people, the oranges are not getting enough heat. They get sun all afternoon every day. I never allow the little growths at the bottom of trunk. I cut them as soon as I see them. Is there anything on the market that I can feed the tree with to sweeten the oranges? I always leave them on the tree until they start falling on the ground, but same problem, sour oranges.
Oranges on Tree When Ripe, Very Sour
Certified GKH Gardening Expert
You have certainly listed many of the reason why the oranges could be sour;
They need lots of warm sunshine, plenty of time on the tree and attention to the root stock.
It very well could be that you have a sour fruit variety. These oranges can be used for jellies.
Also keep in mind that fruit generally improves in sweetness as the tree matures. A 10 year old tree may produce sweeter oranges and in 20 years even better.
I have also heard that some growers say to actually cut back slightly on watering. While citrus need plenty of consistent watering, to much water can cause the fruit to have less flavor.