Lactuca sativa 'Black Seeded Simpson'
vegetableBlack Seeded Simpson is the most popular heirloom loose-leaf lettuce in the United States, dating to the 1850s. Plants form a loose rosette of crinkled, lime-green ruffled leaves with a mild, sweet, fresh flavor and a tender crunch. Named for the dark seed color that distinguished it from earlier white-seeded Simpson selections, it remains one of the fastest, most reliable, and most heat-tolerant loose-leaf lettuces.
Sun
full sun
Water
Every 2 days
Harvest
~45 days
Difficulty
easy
Lifecycle
annual
One season, then done
Spacing
4-6 in. apart
Planting Depth
Surface-sow or 1/8 in. deep
Soil pH
6.0-6.5
Soil Type
Rich, moist, well-draining
Hardiness Zones
Zones 3 – 10
Grown as an annual. This range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
At sowing and when plants are 2-3 in. tall
Fertilizer
Balanced 10-10-10 or 5-10-5 light feed
Direct sow 2 to 3 weeks before the last spring frost and again in late summer for a fall crop, pressing the seed onto the surface or barely covering it - light helps germination. Thin seedlings to 4 to 6 inches apart in rows 12 inches apart. Lettuce prefers cool weather between 50 and 70F; in warm zones, provide afternoon shade in late spring. Keep the soil consistently moist and side-dress with nitrogen once plants are 2 to 3 inches tall to push leafy growth. Succession-sow every two weeks for a continuous supply.
spring planting
Start seeds indoors
Feb 25
Transplant outdoors
Apr 1
Projected first harvest
May 16
fall planting
Direct sow
Aug 25
Projected first harvest
Oct 9
Good neighbors that attract beneficial insects or deter pests
Proactive ways to stop trouble before it starts. Tap a name with an arrow for its full guide
Hose off colonies, plant alyssum nearby for hoverflies, and inspect inner leaves where aphids hide
Use grit barriers, beer traps, or hand-pick at night in the damp cool conditions lettuce likes
Provide afternoon shade once temperatures hit the 70s and keep soil evenly moist - drought and heat trigger bolting
Begin harvesting in about 28 days for baby leaves or 45 days for full size. Cut outer leaves and leave the center crown to keep producing, or shear the whole plant 1 inch above the crown for a single cut-and-come-again harvest. Pick in the cool of the morning when leaves are crisp and store unwashed in a sealed container with a paper towel for up to a week.
Loose-leaf lettuces like Black Seeded Simpson are very low in calories (around 15 per 100 g) and supply vitamin A as beta-carotene, vitamin K, folate, and vitamin C, plus a useful amount of potassium and dietary fiber. Darker outer leaves carry more of these nutrients than the inner pale leaves, so do not strip the outer leaves at harvest if you plan to eat them.
For educational and informational purposes only. HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.
spring planting
fall planting