Start checking on the plants two weeks prior to the maturity date, when there is a five-day window of opportunity to harvest. Depending on the variety, the maturity time will be 75 to 125 days. Examine the plant for bright green pods -- resembling the color of a pea pod -- that are full-size and about 2 1/2 inches long. Check to see if the pods are plump, indicating that they are about 80 to 90 percent full and at peak flavor and nutrient quality.
Pull the plant out of the ground, or cut the plant at the base with a sharp knife, harvesting all of the pods at once, since they developed at the same rate. Grasp the stem of an individual pod and pull it gently to remove the pod from the plant, being careful to avoid squeezing the pod.
Discard of any underdeveloped pods. Chill the pods for three to 10 hours, and market or cook them as soon as possible.