What is an earth tone? Well, Wikipedia has one simple definition which I'll paraphrase for the sake of brevity: " the earth-tone color scheme draws from the browns, tans, warm greys and greens of nature in an attempt to emulate the muted colors of dirt, moss, trees and rocks".
While many of the colors and styles we see on the runways cannot be easily translated into everydaywear, the earthy color palette certainly can. It might seem basic, but it's also fasionable and functional, creating a fresh, natural and understatedly look that varies depending on the fabric.
Nonetheless, your outfit does not have to consist of earth tones exclusively. Yes, you can give your outfit a bit of snap, crackle and pop by including jewel tones or blue tones. And, that's because the most vibrant colors look spectacular next to flat, muddy, dirty hues. I am not sure why, but it is a look I really like. On the other hand, almost all dirt color seem to go with other earth colors....so if you stay in the same range you can play with more hues. And that means you can wear a lot of these clothes with unexpected color you already own.