Hello. I live in Southern California and recently purchased a house that has 2 mandarin orange trees. Last year, the trees did great and produced lots of fruit. Although it was a bit tangy. However, this year one of the trees' leaves started to turn yellow and didn't produce as much fruit. The fruit that it did produce was orange in color with green spots. At first I thought the fruit wasn't ready, but after 2 months and the other tree produced yummy juicy fruit the orange with green spot color remained. I picked one and had a hard time peeling the skin. It stuck to the fuit. The 2 trees are right next to each other and get the same amount of water per day along with fertilizer for citrus trees (from Home Depot, don't quite remember what it was called) every 4-5 months. I hope someone can help me heal my mandarin tree and hopefully even some suggestions as to how to sweeten the fruit. Thanks in advance for any information/suggestions. Ali
Mature citrus trees need fertilizer 3-4 times a yr applied between Feb and Sept. Fertilizer should have trace minerals or they need to be applied separately. For inground citrus a balanced fertilizer will work, but they use fertilizer at a NPK ratio of 5-1-3 and a mature tree needs about a pound of N per yr spread over the 3-4 applications. Climate and timing has most to do with the factors you mentioned. Citrus fruits gain tartness (flavor) during the summer and then begin developing sweetness during cool weather in the fall. The ratio of solids (sugar) to acid (tartness) is often used to determine ripeness and a ratio of 10 is considered good. Peel tightness also changes with time and tends to get looser with time. Skeet
Thanks for the info. I'll try and fertilize a bit more for that tree next month to see if it'll start to turn green again. I just hope it's not some sort of disease because the tree next to it is in great green lush shape. Thanks again. Ali
You might also try giving it some bone meal. I used commercial citrus food for my Meyers lemon which still did just so-so and would get yellowing despite being given iron too; Greek friends whose family do a lot of farming said to give it bone meal, which I have done since with wonderful results. Maybe your Mandarin would be helped also.