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Romaine Cos — Lettuce | DarkGrow Seed Bank

Name: Romaine Cos
Brand: DarkGrow Seed Bank

70-85days to harvest

7-10days to germinate

Z2–11USDA zones

Moderatedifficulty

HeirloomContainer friendly

Sowing

Direct sow 1/4 inch deep in early spring or start indoors. Thin seedlings to proper spacing when 2 inches tall.

Cultivation

Sun: Full sun to partial shade (4-6+ hours)
Water: 1-1.5 inches per week, deep watering preferred
Soil: Well-drained, fertile soil with good organic matter
Soil pH: 6.0-7.0
Spacing: 8-12 inches
Height: 6-12 inches
Season: Cool season

Appearance & flavour

Colour: Dark green with prominent white ribs
Size: 10-12 inches tall, 6-8 inches wide
Shape: Upright, elongated heads with thick, sturdy leaves
Flavour: Crisp, slightly bitter, robust with mineral undertones

In the kitchen

Caesar salad, grilling, wraps, Mediterranean dishes. Essential for authentic Caesar preparations.

Pests, disease & resistance

Pests: Aphids, leafminers, cutworms, flea beetles
Diseases: Downy mildew, bottom rot, tipburn, bacterial leaf spot
Resistance: Moderate resistance to tipburn, susceptible to bottom rot in wet conditions

Planting calendar by USDA zone

Zone	Start indoors	Transplant	Direct sow	Harvest
1	—	—	June – July	August – September
2	—	—	May – July	August – September
3	—	—	May – June	July – October
4	—	—	April – June	July – October
5	—	—	April – May	July – November
6	—	—	April – May	June – November
7	—	—	March – May	June – November
8	—	—	March – April	May – December
9	—	—	February – March	April – December
10	—	—	January – March	April – December
11	—	—	January – February	March – December
12	—	—	January – February	March – December
13	—	—	January – February	March – December

Companion planting

9 beneficial pairings indexed for this variety, 3 to avoid.

ChivesRepels aphids and improves lettuce flavor while providing natural pest deterrent

CarrotsDeep roots don't compete with shallow lettuce roots, maximizes garden space efficiently

RadishesQuick-growing companion that loosens soil and deters flea beetles

MarigoldsRepels aphids, whiteflies, and other pests that commonly attack lettuce

DillAttracts beneficial insects like ladybugs and lacewings that control aphids

GarlicNatural fungicide properties help prevent lettuce diseases and repel pests

NasturtiumsActs as trap crop for aphids and cucumber beetles, protecting lettuce

SpinachSimilar growing requirements and harvesting times, efficient space utilization

ParsleyAttracts beneficial insects and provides ground cover without competing for nutrients

Avoid

BroccoliHeavy feeder that competes for nutrients and may shade lettuce excessively

FennelReleases allelopathic compounds that inhibit growth of lettuce and most vegetables

SunflowersAllelopathic effects suppress lettuce growth and tall plants create excessive shade

Nutrition (per 100 g)

Calories (per 100 g): 17
Protein (g): 1.23
Fat (g): 0.3
Carbohydrate (g): 3.29
Fibre (g): 2.1
Sugars (g): 1.19
Vitamin A (µg): 436
Vitamin C (mg): 4
Vitamin E (mg): 0.13
Vitamin K (µg): 102
Vitamin B6 (mg): 0.074
Folate (µg): 136
Calcium (mg): 33
Iron (mg): 0.97
Magnesium (mg): 14
Phosphorus (mg): 30
Potassium (mg): 247
Zinc (mg): 0.23
Selenium (µg): 0.4

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Where to buy seed and equipment

Some links are affiliate links. If you buy through them we may earn a commission at no extra cost to you.

Growing it? There is a full cultivation guide at the lettuce growing guide.

Cultivar facts compiled from public horticultural references including USDA GRIN and NC State Extension. Descriptions are original to this catalogue.

Romaine Cos

Sowing

Cultivation

Appearance & flavour

In the kitchen

Pests, disease & resistance

Planting calendar by USDA zone

Companion planting

Avoid

Nutrition (per 100 g)

Where to buy seed and equipment

Grown Romaine Cos?

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