This is what I gleened from the Arenanet forums while they were up...(I forget the name of the original poster, sorry)...
Lettuce farm in Queensdale, south of Beetletun in the topmost farm area.
Potato farm 1 is directly south of the Loreclaw Waypoint in the Plains of Ashford.
Potato farm 2 is in Wayfarer Foothills scattered around The Osenfold Shear.
Strawberry patch 1 is in Kessex Hills, at Isgarren’s View. Carefully go down the cliff edges to farm all 8 nodes.
Strawberry patch 2 is in the southeast corner of Snowden Drifts, at the bottom of a cliff near Griffonfall.
Hidden cave with a strawberry patch maintained by one a charr girl that involves some exploring and jumping.
Spinach farm in northern Gendarran Fields west of Povemic crypt.
Spinach patch a bit outside of Lion’s Reach to the West, up on a tier, but there might be a jumping puzzle to reach it.
I don't see how knowing the location of these farms spoils the fun of gathering and cooking at all, especially since they regrow in the same place 23 hours later.
Edited by AmusingMoniker, 17 June 2012 - 08:59 PM.