Lettuce is a fickle summer crop, usually refusing to grow into a decent sized plant before turning bitter and sending up a seed stalk. Seed catalogs always list a few lettuce varieties they describe as being 'heat resistant.' I always think, "yeah, 'heat-resistant' in northern Maine, but Southern California's heat is probably a different critter."
To satisfy my curiosity, I started five different types of lettuce offered by Pine Tree Seeds (of Maine) for a trial. Three of the five are in this photo, Red Sails, Red Fire and Bughatti. The other two, Summertime and Jericho haven't been transplanted like these three into one per cell six packs. We sowed each lettuce, initially five per cell, which should net us 30 seedlings. Summertime's germination was so lousy, we won't even get five. Jericho's germination was sufficient, but slower than these three.
Bughatti is the very (very) dark lettuce in the upper left, with Red Sails the smallest lettuce in the upper right. The bottom two six packs are filled with the vigorous Red Fire.
But the main criteria will be that they perform well enough to grow an edible head that is not bitter even in Los Angeles heat.
We'll have further updates as they mature.