Rouge Grenobloise is a Batavian (crisphead) type of lettuce from France. I will be comparing this lettuce to Red Sails, one of my favorites.
Mar 10, 2016 = Day 0. Plants started from seed (Botanical Interests, Bountiful Gardens). Seeds sowed in 1.5-inch rockwool cube in 2-inch net-pot. Moistened with dilute fertilizer solution: 1.2 mL Dyna-Gro GROW 7-9-5, 0.8 mL pH Down per gallon of tap water. N-P-K (in ppm): 22-12-13. pH = 6.0.
Mar 12 = Day 2. Plant germinated, placed directly under a fluorescent light (2 ft. T8 bulb, 17W, 6500k) for 16 hours per day.
Mar 22 = Day 12. Installed plants into 3.5-gallon bucket. Hydroponic solution composed of 3.5 gal (13.2 L) tap water, 7 g MasterBlend 4-18-38, 7 g calcium nitrate, 3.5 g magnesium sulfate, 0.7 mL Dyna-Gro Pro-TeKt, 3.5 mL pH Down. N-P-K (in ppm): 103-41-168. pH = 6.0. Plants moved to indoor grow room, receiving 9 hours LED grow light per day, plus 3 hours sunlight per day.
Apr 26 = Day 47. Started harvesting lower leaves. Plants appear identical.
May 19 = Day 70. Both plants were quite large and were falling over. Harvested all leaves.
At the end of this comparison between Rouge Grenobloise and Red Sails, it is clear that there is no noticeable difference in yield, color, quality, or taste.