Q.Gardenias in Southwest Florida
We live in Naples and the weather here is very warm and humid except for our winters, which get down to the mid 40’s for a few days then back up to mid 60’s. March temps are back into the 70’s and 80’s. Our gardenia tree/plant is located outside in our lanai. I added used coffee grounds to the soil about 2 months ago and it’s been doing very well, producing 8 to 10 flowers. Questions: When, for this area we live in, is this gardenia plant to be fertilized? And, how often does it require feeding? What type of plant food does it require for this area?

How wonderful your gardenia is blooming!
You should fertilize your gardenia in the spring and summer.
Here is an excellent article that will help you establish a fertilizing schedule for your plant.