Valley Flora Farm (Langlois) and High Prairie Farm (Brookings) each grow a variety of leeks, which are harvested generally in the spring and again in the fall. Both farms grow using organic practices.
Leeks should be stored in the crisper and not rinsed until just before you use them. To use:
1) Cut the greens off the whites, leaving about an inch of green attached to the white; 2) Cut off the root, exactly where it joins the white; 3) Trim off the outermost green leaves left attached to the white; 4) Cut the whites in half lengthwise (if you want to leave the white whole, leave about 1/2 inch of the root end); 5) Hold the leek whites under cold running water with the cut side up. Rub each layer between thumb and forefinger to detach any grit.