Trigger Crisphead Lettuce Seed - Certified Organic Iceberg Type
Trigger Crisphead Lettuce Seed is open pollinated. (75 days) This superb Calmar-type iceberg lettuce is right on target. It looked good in three consecutive Colrain, MA, trials, making nice firm big heads while showing real reluctance to succumb to BOR even when left overcrowded under difficult conditions of excessive rainfall.
Has shown high tolerance to cold as well as moderate ability to withstand heat. Its very crinkly toothed leaves fold into tight, tight hard 7–10" medium-green heads without give. “Vigorous and crunchy, sweet and juicy,” extol my trial notes. Attractive, marketable and never bitter.
About 300+ seed per pack. 92% germination.
Lettuce Culture: May be started indoors in March and at regular intervals thereafter, or sowed outdoors as soon as ground can be worked. Many varieties won't germinate in soil temperatures above 75° and most shut down above 80°. Where available, we present data here from a California germination experiment at 84°.
Hardy. All lettuces except icebergs tolerate heavy frost. They grow best in cool weather with medium moisture. Use shade cloth to keep summer lettuce tender and sweet longer.
Sow every 2 weeks for continuous supply. Lettuce will not head unless thinned frequently and ruthlessly to final distance of 1'. Heavy nitrogen feeders.
Minimum germination soil temperature 35°, optimal range 40-80°, optimal temperatures 70-75°. Emergence takes 3 days at 68°soil temperature.
Days to maturity are from direct seeding.