Japanese Mandarin tree
My Asian neighbour has a Japanese Mandarin tree that had lovely sweet fruit its first year but, ever since, the fruit is very bitter. Last year I suggested he leave the fruit on till it had fully ripened to develop the sugar, thinking he was picking it too early but it was still bitter. Please, any advice would be appreciated.
Certified GKH Gardening Expert
It would actually help to put down some potassium and phosphorus fertilizer, and some iron sulfate. This will help sweeten the fruit, as this can happen when the soil is lacking some trace minerals. Applying these will help the tree produce sweeter fruit, as it will replenish what is lacking in the soil.