The Random House Historical Dictionary of American Slang 1994 Vol 1.
green n. 1. GREENHORN 1. Mil & Naut a raw recruit
1825 in OEDS:It appears that George Charteris....had been "doing" the green, and taking in the "deep one," quite in the gull-catching style.
1888 in OED The master sweater gets hold of a new hand, a greener, as he is termed, and pays him a shilling a day.