Bolt-resistant lettuce can help extend harvest season

By Reeser Manley,
Posted June 11, 2010, at 10:04 p.m.

I come out of winter craving fresh green leaves. Like our two dogs, Dixie and Reilly, who stop every few feet along our early morning walks to graze on the first green blades of grass growing in the roadside ditch, I relish the leaves of lettuce picked in early morning, still covered with dew and full of sugar.

Something missing from our diets through the long winter has returned, and we cannot get enough.

By early June, just-picked lettuce has become daily fare. Bent over the garden bed in early morning with the sun just rising over the tree line along the distant riverbank, I harvest a few leaves from every plant. Sweet, succulent leaves of Winter Density, a green romaine-type just starting to form tight heads, and frilly red leaves from open heads of New Red Fire. Pick it now, before the sun hits it and the sweetness is lost.

Grow lettuce now, before the weather turns hot and the lettuce heads bolt, leaves acquiring a bitter taste as the plants switch gears from foliage to flowers. Last summer was a good lettuce summer, cool and wet, and successive sowings of slow-bolting varieties kept us in fresh lettuce longer than in most years.

I read with interest a report on research done at Colorado State University on the bolt resistance of 50 different cultivars of six types of lettuce. Combining the results of this study with recommendations in Johnny’s Selected Seeds catalog, the following varieties stand out as the best choices for Maine gardeners trying to extend the lettuce harvest with successive sowings.

Johnny’s rates Tropicana and Green Star as the best of the green leaf lettuces, while the Colorado study rated Concept and Envy as green leaf types that remained edible through the hot High Plains summer. Both Tropicana and Green Star also have excellent resistance to tip burn, a lettuce disease caused by calcium deficiency and often related to rapid growth of lettuce in warm weather.

Among the red leaf lettuces, New Red Fire and Red Salad Bowl led the pack in the Colorado study. Johnny’s recommends Red Sails as the slowest-bolting red leaf variety with excellent tip-burn resistance.

I am particularly fond of the succulence and sweetness of romaine lettuces. Among this group, Green Forest and Rouge D’Hiver stood out as the most bolt resistant green and red varieties, respectively, in Colorado trials. Johnny’s recommends Winter Density as a bibb-romaine lettuce can grow year-round and tolerate frost, as well.

In general, the Batavian lettuce varieties (also called summer crisp and French crisp varieties) proved most bolt-resistant in the Colorado trials and come highly recommended for hot weather by Johnny’s. Like the romaine lettuces, the leaves are succulent, crisp, and sweet. Young plants are open, like loose-leaf varieties, maturing to heavy, compact heads. Nevada is a recommended green-leaf variety, while Cherokee is a red-leaf form that is very slow bolting.

I seem to want my cake and to eat it, too — a tomato summer with never-ending lettuce. The best combination I can come up with is the Siberian tomato variety mentioned in last week’s column, Black Prince, and a succession of lettuce sowings with the varieties mentioned above.

While on the subject of greens, I’d like to share the following letter from Lurleen Webb of Prospect:

“I read your column every weekend and I wish to comment on your article of Sat-Sun, May 8-9.

You wrote about dandelions and you didn’t mention eating them. In early Spring we dig them, boil them, sometimes with a piece of salt pork, or butter — yum, yum!”

Thank you, Lurleen. I’ve heard that earliness is important with dandelion greens. Like lettuce, when dandelions start to flower, the leaves become bitter.

http://bangordailynews.com/2010/06/11/living/boltresistant-lettuce-can-help-extend-harvest-season/ printed on August 1, 2014