Tine weeding, also called blind harrowing, is a favorite technique among organic grain farmers—45' wide tine weeders are not an uncommon sight on organic fields in the Midwest and Canada.
Now, thanks to Two Bad Cats, this technology is available for those operating on a smaller scale. Two offset rows of flexible tines, spaced 1½" apart, span 18" across and will go around your established plants (and your drip tape!) without disturbing them, but will wreak havoc on barely germinated weeds. Handle is 56½" long with adjustable angle.
Like so many farm and garden activities, this tool requires well-timed use to be truly effective.