Black Seeded Simpson

Lettuce

45d to harvest

Sink your senses into Black Seeded Simpson’s tender, buttery leaves—cool, crisp, and delicately sweet with a clean, garden-fresh snap. Forming a compact, romaine-leaning head, it delivers a velvety texture that stays crisp in the bowl and shines in fresh salads. Ideal for early-season harvests at about 45 days, this classic lettuce rewards home gardeners with dependable, uniform heads and a beautifully mild flavor.

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	May 15th
Transplant / Sow Outdoors	May 8th
Harvest Begins	Jun 22nd
Harvest Ends	Aug 25th

Crop Details

Trait	Value
Days to Maturity	45
Sun Requirements	Part Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Surface
Germination Temp (°F)	70
Min Soil Temp (°F)	40
Min Night Temp (°F)	35
Harden Off (days)	5

Frequently Asked Questions

How do I prevent and treat lettuce downy mildew (and similar fungal issues) on Black Seeded Simpson?

Watch for yellow-green patches on leaf tops and a grayish-purple fuzzy growth on the undersides—especially after cool, humid, damp mornings. Remove and discard the worst leaves, improve airflow by spacing plants a bit more, and water at the base in the morning so foliage stays dry. If it keeps spreading, use a labeled fungicide that targets downy mildew on edible leafy greens and follow the label’s reapplication interval.

How often should I water Black Seeded Simpson during the main growing phase (after germination)?

Keep the soil evenly moist but not soggy from transplanting/germination through leaf formation, typically watering about 1–2 times per week depending on heat and soil. Aim for topsoil that feels lightly moist 1 inch down—drying all the way out causes bitter, bolting-prone lettuce, while constant wetness invites fungal problems. In warm spells, you may need brief, more frequent waterings to maintain that “damp, not wet” condition.

How can I tell when Black Seeded Simpson is ready to harvest at about 45 days?

Harvest when the outer leaves are full-sized and reach your desired size (often around 4–6 inches) and before the center begins to elongate or bolt. You can do “cut-and-come-again” by snipping outer leaves for multiple harvests, or take the whole head/rosette when it’s evenly filled. If leaves taste increasingly bitter or you see a tall flower stalk starting, harvest immediately.