Start seeds 4 to 5 weeks before last spring frost. Sow 1 inch apart in seed starting mix, cover 1/4 inch deep and keep evenly moist. Provide a strong light source until seedlings are ready to plant out. When several inches tall, transplant seedlings 10 inches apart into rich soil in full sun, after gradually acclimating to outdoor conditions.
Baby Napa cabbage needs full sun and rich, well-drained soil to produce firm, sweet heads. To avoid stunting growth, don’t let seedlings get crowded before thinning or transplanting. Keep weeded and evenly watered. Feed monthly with fish emulsion or an all-purpose fertilizer; strongly growing, healthy plants resist pests much more successfully. Use non-toxic B.T. (Bacillus thuringiensis) for caterpillar pests. Floating row covers provide a good barrier method to exclude pests. Remove covers when heads begin to form.
HARVEST AND USE
Cut the 8 to10 inch tall vase-shaped heads when they are very solid and well-formed and about 4 to 6 inches wide.