Pak Choi, White Stem 

45 Days
Often called Bok Choy in grocery stores, it's very popular for Oriental cooking, especially for stir-fry. Crispy, celery-like white stalks and rounded, glossy green leaves are delicious. Good raw, too. Grows very quickly, producing upright clusters of 6 to 12 stalks. Loves cool weather, so plant as early as you can work up the garden. Make successive small plantings one week apart for 3 weeks, then quit planting to avoid maturity when the weather is too hot. Plant again in the fall when temperatures are moderate.