Many kinds of lettuce will blot quickly in warm/hot weather. You can construct a sunshade from old window screens to extend the life of your spring lettuce and you can plant more heat tolerant varieties. The list below is from Suite 101.
Many garden stores and the garden section of the big box stores still have lettuce seeds and seedlings. For the cost of one little flat of seedlings (around $3 - $4) you can get a packet of seeds. We like to get a variety and make our own blend. This year, Red Sails, Butter Crunch, Black Seeded Simpson and Oak Leaf.
Heirloom lettuces which can take a bit more heat than their near cousins are listed below.
- Buttercrunch is a bibb-type lettuce with a tight center rosette and dark green leaves.
- Brown Mignonette is a butterhead lettuce which produces small, flavorful, compact heads early in the season. Edges of leaves have a dark green to red-brown coloring. This is a good variety for those with small gardens.
- Merveille de Quatre Saisons is a bibb-type lettuce with a compact green heart and reddish-purple tipped leaves.
- New York Head is an iceberg-type heading lettuce which grows very large possibly reaching four pounds. It is very sweet and tolerates heat and cold equally well.
- Oak Leaf lettuce is a loose-leaf variety with both green and red leaves. Growing this variety will add color plenty of to spring and summer salads. This is a dependable ‘cut-and-come-again’ plant.
- Red Romaine lettuce or cos is a leafy lettuce with a crisp texture which grows on stalks rather than close to the ground like other leaf lettuce. Like its name suggests, red romaine has red leaves.
- Rouge De Grenoblouse is an extremely bolt-resistant crisphead lettuce. It has a very sweet flavor even when grown in hot climates.
- Rouge De Hiver or Rouge d’Hiver is a romaine lettuce with sweet, buttery flavor. It has very large leaves and is dependable in the heat.
- Simpson Black Seeded lettuce is a loose-leaf variety with light green curly leaves. This is the old time favorite most gardeners have heard of. It matures early and is also a good ‘cut-and-come-again’ lettuce.
- White Boston is a butterhead lettuce which produces light green heads with a creamy-yellow heart. Heads are firm, round and approximately twelve inches. It is extremely heat-tolerant and recommended for Florida gardens.