All lettuce is open-pollinated.
1 gram packet sows 25 ft; 2 grams, 50 ft; 1 oz, 500–700 ft. Varieties average 875 seeds/1g pkt, or 1,750 seeds/2g packet.
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 save icebergs tolerate heavy frost. Grow best in cool weather with ample moisture, many kinds suffer bottom rot and tipburn in heat; select summer varieties carefully. 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.
The snowflake symbol after a cultivar description indicates that a variety is hardy through at least a part of our Maine winter.
Minimum germination soil temperature 35°, optimal range 40–80°, optimal temperatures 70–75°. Emergence takes 15 days at 41°, 7 days at 50°, 3 days at 68°, 99% normal seedlings at 77° but only 12% normal at 86°.
Days to maturity are from direct seeding.
- BOR: Bottom Rot
- DM: Downy Mildew
- PM: Powdery Mildew
- SC: Sclerotinia
- TB: Tipburn
- X: Xanthemonas
Pest: Aster Leafhopper (vector for Aster Yellows disease)
Cultural controls: control perennial broadleaf weeds near lettuce plantings, plow lettuce fields immediately after harvest.
Cultural controls: avoid mulch or nearby grassy areas.
Disease: Bottom RotDiseases:
Cultural controls: rotate with grass-family green manures, plant in well-drained soil or on raised beds, more upright varieties escape infection.
Downy Mildew, Grey Mold, White Mold
Cultural controls: rotation, reduce duration of leaf wetness, plant parallel to prevailing winds, use wide spacing, control weeds, use well-drained fields in spring and fall.
|1 gram||=||.035 oz|
|2 grams||=||.070 oz|
|4 grams||=||.141 oz|
|14 grams||=||.494 oz|
|28 grams||=||.987 oz|
|112 grams||=||3.95 oz or .247 lb|
|448 grams||=||15.79 oz or .987 lb|
|1⁄16 oz||=||1.77 g|
|⅛ oz||=||3.55 g|
|¼ oz||=||7.09 g|
|½ oz||=||14.2 g|
|1 oz||=||28.4 g|
“I wish my work to be shared, not monopolized.”
–Lettuce breeder extraordinaire Frank Morton
Genetic engineering is not the only ethical issue in seed production. A new and disturbing trend in lettuce is the prevalence of trait- and utility-patented varieties in seed catalogs. One of our competitors listed more than one third of its lettuce varieties and 10 of 14 of its new offerings last year as utility- or trait-patented. Utility patents stand the traditional rationale for variety protection on its head. The original reason advanced in its support was to offer breeders an economic incentive to develop new varieties for agricultural improvement. Utility patents, by extending ownership beyond individual varieties to their traits (such as heat tolerance and leaf color) that are found in nature, stultify any possible future breeding improvements by monopolizing those traits and uses that rightfully belong to the commons, cutting off any further opportunity for any other breeder to work with them. Once traits are tied up in private hands, varietal improvement comes to a halt. You will not find any trait- or utility-patented varieties at Fedco because such patents are against our ethics. Free the seed! Use seeds in the public domain and shun utility-patented varieties. Click here for more information. Morton also has great essays in more depth on these topics in his recent seed catalogs.