Britain is known for introducing us the best of the best — think Princess Diana, Harry Potter and fish and chips. Now we can thank the UK for bringing us a fantastic sun safety idea: the 3-hour-gardening rule. The concept is simple: don’t go out in the sun to tend to your plants during its strongest rays, which generally occurs between 11 AM and 2 PM. After British gardener Shannen Goodwin explained that the 3-hour gardening rule can offer powerful protection from sun-related health problems, the internet took note and the idea went viral. Really, though, the 3-hour rule is…