The Karaites start their year by observing "Abib", that is, when the barley crop is in a particular state of growth. Many Torah keepers have adopted this practice too.
Rich Lobert wrote this article, Choose Your Barley - The Barley/Equinox Question, Part I and Choose Your Barley - The Barley/Equinox Question, Part II.
People who start the New Year by the barley harvest are often quick to say that using the vernal equinox to determine the start of the year is "pagan astrology". If it is, then so is sighting the new moon. But keeping the new moon feast is commanded by YHWH.
Rich Lobert writes that there are many varieties of barley. Even in Israel, the domestic barley matures at a different rate than the wild barley. Would YHWH command us to use a method of time keeping that forced us to travel to Israel every year? Some varieties of barley would force us to have a 14 month year.
Although I side with the Karaites, Rich Lobert raised some important issues which urgently need answers. I encourage you all to read his article linked above.