Lettuce - Introduction S/N - Lectuca sativa L. Family - Asteraceae Temperate annual plant Mostly use as leaf vegetables Lettuce – Health benefits Low in Saturated Fat & Na Very low in Cholesterol Good source of Vit B 6 , Ca & Mg Very good source of Fiber, Vit A, Vit C, Fe, K & Mn Reduces risk of cancer, and heart disease Source: Nutrient data provided by USDA SR-21 1. Butterhead- . Buttercrunch 2. Loose leaf- eg . Salad Bowl 3. Cos or Romaine- eg . Red Rosie 4. Crisphead - eg . Great Lakes 5. Stem or asparagus lettuce- eg . Celtuce Lettuce - Cultivars Lettuce - Production Soil - Loamy sands/sandy loams & well drained Temperature - In summer average 87 o F, In winter average 55 oF Fertilization - N: 60 to 100 lbs, P 2O 5 : 80 to 120 lbs, & K 2 O: 60 to 170 lbs per acre. Generalized rate (lbs/A): 70-80-120. Irrigation - 38 to 50 inches of water per acre Lettuce - Production Temperature: Seed Germination – Optimum 70 to 75 oF Growth & Development – Optimum 55 to 60 oF pH: to Amount of seed/acre - 16 to 20 oz. Lettuce - Production Planting depth of seed - 1/4 to 3/8 ? Row width - 60 ? In-row spacing - 12 ? in double rows Days required to grow - 40 to 60 days Plants/acre - 20,000 to 46,000 plants Lettuce – Insects Management Aphids Armyworms Cutworm Management - Crop rotation, destruction of crops residues, & IPM Loopers Leaf miners Lettuce – Diseases Management Bottom rot Mildews Lettuce mosaic Grey mold Damping-off Leaf drop Management: -Use resistant varieties & well drained soil Lettuce - Harvest Hand Harvest - 40 to 60 DAP Containers - Field cartons 18 - 30 heads each Grades - Graded based on defects & head firmness Average yields - 22,500 lbs/A (400 to 500 24- head cartons) Packaging/Handling - 40 - 45 lb fiberboard boxes; immediate cooling (preferably vacuum type) Storage temp & RH – 32 o F & 95% (2-3 wks) Transit temp & RH – 32 o F & 98% Lettuce - Post harvest
