Now's a Good Time to Have Some Manure!

It's time to fertilize all of your citrus plants. This includes everything from kumquats and loquats to lemons and limes. Citrus tress should be fertilized three times a year: before and after blooming then once more in the fall to maintain the nutrients they need to give you the fruit you love.

Citrus tress prefer low levels of phosphorus, so you need to check the packaging before you go dumping some chemical fertilizers on the roots. Fertilizer labels are always in order of Nitrogen, Phosphorus, and then Potassium in the product information. So look for something with a 5-2-6 or similar formula.

from lowes.com

This bag is "7-1-2". So it's high in Nitrogen, but low in Phosphorus and Potassium. If you use this, you may want to beef up the Potassium with a second fertilizer. 

from sarasotafruitandnutsociety.org

Loquats!

from wikimedia.org

Lemon!