Marianne's Response

Rate for feeding a potted Calamondin tree

Marianne –

I have a dwarf orange tree (Calamondin: x Citrofortunella microcarpa) that’s over 35 years old. I recently pruned its roots and repotted it in a 9 gal. planter. I also bought Osmocote Plus because the fertilizer I had been using for the tree is no longer produced. According to the Osmocote directions I should use “1 capful per 2 gal. pot” which in my case would be a little over ¾ cup. However, below those directions it also says, “½ outdoor rate for indoors.” The potted tree is outside from late spring to early fall, then indoors for the winter. Should I use the outdoor rate or the indoor rate for feeding the tree? Or is it both, depending upon where it is?

Thanks for your help.

Posted by Jeff Ross on August 12, 2019

Marianne's Response

Hi Jeff, your tree is lucky to have you give it such excellent care. No wonder it is over 35 years young. I recommend you use the indoor rate on your orange tree as it will be dormant when indoors this winter and is better to have a little less plant food rather than a bit too much when it comes to potted indoor plants. The good news about using Osmocote is that the fertilizer will not be released until the plant needs it. A combination of moisture and warm soil is what causes the nutrients to be released so you do not risk fertilizer burn when using Osmocote as recommended.  Repotting and root pruning were both good ideas and after a bit of a rest this winter your potted tree will have some great growth the following summer. Keep growing, Marianne Binetti