Miami Beach Botanical Garden

Best part about Miami Beach Botanical Garden is the fact it is free. It's only open Tuesday - Sunday from 9 am - 5 pm and would be nicer if open later, but still a great garden and a very serene and relaxing place in the middle of busy Miami. They also have great free events and seminars here. Wednesdays they have Yoga in the park for $10 at 12:30.

I'd recommend going Wednesdays for the farmer's market. It runs from 11 am - 4 pm every Wednesday and has so many tasty offerings. Also on Wednesday is the Orchid exchange where you can return your non blooming plant for one in bloom. It runs from 11-5 pm.