- A popular variety for salads with narrow, upright heads.
65-70 days. Dark Green COS Romaine Lettuce Seeds. Lactuca sativa. Non-GMO. Open Pollinated. Its dark green leaves are long, narrow, and very crisp. The leaves are dark green in color and are popularly used in Caesar salads for their sweet and mild flavor. Like most lettuce varieties, Dark Green Cos grows well in containers. Maintain a regular watering schedule. As a cool-season plant, lettuce is best sown in the spring and fall months. ~25,000 seeds per oz.