How to grow lettuce

Hardiness

Lettuce withstands light frosts. Hardiness note on their sheet — not a freeze-proof claim.

Temperature

Lettuce is a cool-season crop; their sheet lists temperatures of 55 to 65°F. Temperature range on their sheet — not a BioArva climate zone.

Spacing

Plant leaf lettuce in rows 1 to 2 feet apart with seed one-quarter inch deep and 6 to 10 inches apart in the row; they say it is usually necessary to plant thicker and thin. Spacing on their sheet — not a BioArva average.

Thinning

Leaf lettuce should be thinned when the plants are 1 to 2 inches tall. Thinning stage on their sheet — not a BioArva instruction set.

Germination

Their sheet lists soil temperature for seed germination of 60 to 80°F, and says raw lettuce seed will not germinate at a soil temperature above 95°F. Germination range on their sheet — not a BioArva climate zone.

Spacing

Leaf lettuce can also be planted in 12-inch-wide beds with the seed broadcast over the bed. Spacing on their sheet — not a BioArva average.

Spacing

Head lettuce should be planted in rows 3 feet apart with 12 inches between plants in the row. Spacing on their sheet — not a BioArva average.

Seed

Their seed-starting note distinguishes potting soil from garden soil for covering lettuce seed. Source-specific seed-covering note—not a BioArva mix recipe or product SKU.

Start

They list growing head lettuce from transplants. Source-specific start method — not a ranking of sources and not a BioArva instruction set.

Types

Butterhead or Bibb lettuce is a loose-heading type with dark green leaves that are somewhat thicker than those of iceberg lettuce. Type note on their sheet — not a ranking.

Limit

South Carolina HGIC 1312 only. Spacing is not averaged with Maryland.

Hardiness

Lettuce is a semi-hardy annual; it can withstand light frosts but needs protection against heavy frosts or freezing. Hardiness on their sheet — not a freeze-proof claim.

Sun

Lettuce tolerates partial shade (4–6 hours of direct light per day); their sheet also lists full sun in spring and fall. Light note on their sheet — not a ranking of sites.

Timing

Sow leaf or butterhead types as soon as soil can be worked in the spring, or in late summer; crisphead and cos (romaine) types may be transplanted in early spring and fall. Timing on their sheet — not a national calendar.

Spacing

Leaf, cos, or butterhead 4–10 inches in-row by 12–24 inches between rows; crisphead 12–15 inches in-row by 20–30 inches between rows. Spacing depends on harvest stage on their sheet — not a BioArva average.

Start

Their sheet lists 3 to 4 week old transplants. Timing note on their sheet — not a yield promise.

Container

Their sheet lists lettuce in containers. Container note on their sheet — not a ranking of pots vs ground and not a BioArva pot size.

Shade

Plant long-season lettuces so that crops such as sweet corn, staked tomatoes, pole beans, or deciduous trees will shade the lettuce during the hottest part of the day. Shade timing on their sheet — not a companion ranking.

Sun

Baby leaf lettuce can be grown entirely in indirect light in summer. Light note on their sheet — not a ranking of sites.

Timing

Leaf lettuce on their sheet can be grown from March to December with a break in July and August. Geographic calendar on their sheet — not a national plant date.

Spacing

Sow 10 to 20 seeds per foot of row; thin individual plants 4- to 8-inches apart, depending on variety. Spacing on their sheet — not a BioArva average.

Mulch

Organic mulches are helpful in conserving soil moisture and maintaining even soil temperatures. Cultural note on their sheet — not a BioArva mulch program.

Maturity

Days to maturity 40–80, depending on the type. Timing on their sheet — not a yield promise.

Culture

Cultivate carefully, as lettuce is shallow-rooted. Cultural note on their sheet — not a BioArva instruction set.

Water

Their sheet lists frequent, light watering; for overhead watering, it specifies morning so plants have time to dry during the day. Water note on their sheet—not a BioArva irrigation schedule.

Harvest

Their Cut and Come Again harvesting note describes sowing a raised bed thickly and cutting plants right above ground level with sharp scissors. Harvest method on their sheet — not a BioArva yield promise and not a title claim.

Shade

Their spring succession note describes using tall crops and trellises to shade late-spring lettuce plantings. Source-specific planning note—not a companion ranking or a BioArva calendar.

Limit

Maryland lettuce sheet only. Spacing and calendar are not averaged with Clemson.