Lactuca sativa var. longifolia
vegetableRomaine, or cos lettuce, forms a tall, upright head of sturdy, elongated leaves with crisp ribs and a sweet, robust flavor, the classic lettuce for Caesar salads. More heat- and bolt-tolerant than tender butterheads, it matures in about 70 to 85 days and holds its quality well in the garden and the refrigerator.
Sun
full sun
Water
Every 2 days
Harvest
~70 days
Difficulty
easy
Lifecycle
annual
One season, then done
Spacing
8-12 in. apart
Planting Depth
1/4 in.
Soil pH
6.0-7.0
Soil Type
Rich, moist
Hardiness Zones
Zones 3 – 9
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
About 3 weeks after transplant
Fertilizer
Nitrogen-rich (21-0-0)
Direct sow or transplant in cool weather, spacing plants 12 to 16 inches apart in fertile, evenly moist soil in full sun, and sow successively for a continuous supply. Keep moisture steady for crisp, sweet leaves, and grow the crop to mature before summer heat, which pushes romaine to bolt and turn bitter; afternoon shade helps in warm climates.
spring planting
Start seeds indoors
Mar 18
Transplant outdoors
Apr 1
Projected first harvest
Jun 10
fall planting
Direct sow
Jul 28
Projected first harvest
Oct 6
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
Interplant alyssum and herbs to draw hoverflies; inspect leaf undersides
Water in the morning so beds dry by night; trap and hand-pick after dark
Use row cover over seedlings
Pick outer leaves as needed, or cut the whole upright head at the base once it is full and firm, harvesting in the cool morning. Romaine can be cut an inch above the crown to regrow for a second cutting, and it holds longer after harvest than softer lettuces.
Romaine is low in calories and an excellent source of vitamins A and K, with folate, vitamin C, and more nutrients and fiber than paler lettuces, plus a satisfying crunch.
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