Castor Oil Plant

My Castor Oil seedlings are coming on nicely, but they are completely green.  They are from the same batch of seed that I grew last year, which was the dark red variety (collected when I was in Corfu a few years ago).  Do the seedlings take a while to turn dark red? I seem to recall last year that the seedlings were dark red from the minute they germinated, but perhaps they took longer to turn colour than I remember.