If they are left on the tree for a while after they turn orange, they will become sweeter with time. Once an orange or a clementine is picked, however, it will not ripen further. It may become softer as it rots, but the sugars will not develop and quality of the fruit will not improve.

How do you make tangerines sweeter?

Use potash and Epsom salts to grow sweeter citrus fruit. Sprinkle approximately 6 handfuls of sulphate of potash around the base of each citrus tree. Dissolve 2 tsp. of Epsom salts into 2 1/2 gallons of water.

Does citrus sweeten after picking?

Citrus trees (Citrus spp.) grow throughout U.S. Department of Agriculture plant hardiness zones 9 through 11. Unlike some other fruits, citrus fruits do not continue to ripen or get sweeter after you have harvested them off the tree. So, it’s best to leave the fruit on the tree until it is fully ripe.