Parris Island Cos

Lettuce

65d to harvest

Crisp as fresh-cut glass, Parris Island Cos forms tall, elegant heads with a tender, sweet bite and a clean, leafy snap. The leaves are deep, cool green with a softly ribbed texture, building into a sturdy romaine silhouette that holds its shape through the season’s swings. Ideal for fresh salads and vibrant platters, Parris Island Cos also shines when you want a romaine-forward base for dressings, wraps, and quick tosses—its heirloom flavor stays bright and never turns bitter too soon.

Crop Dates

Milestone	Date
Start Indoors	Apr 27th
Last Frost	May 25th
Transplant / Sow Outdoors	May 25th
Harvest Begins	Jul 29th
Harvest Ends	Aug 29th

Crop Details

Trait	Value
Days to Maturity	65
Sun Requirements	Full Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	40
Min Night Temp (°F)	35
Harden Off (days)	7

Frequently Asked Questions

How do I prevent and treat downy mildew and lettuce drop in Lactuca sativa (Parris Island Cos)?

Keep lettuce beds well spaced and avoid wetting leaves when watering, because Lactuca sativa is prone to downy mildew and related “lettuce drop” under cool, damp conditions. If you see yellow patches or fuzzy growth on leaf undersides, remove infected plants immediately and improve airflow (thin/space to about 8–12 in between plants). Avoid replanting lettuce in the same spot for at least one season and keep weeds down to reduce humidity around the plants.

How often should I water Parris Island Cos during the main growing phase?

Water deeply so the top 1–2 inches of soil stays consistently moist, especially from the time seedlings establish through head/leaf filling (typically weeks 3–8). In full sun, plan on roughly 1 inch of water per week total (adjust for heat/rain), and water at the soil line in the morning to prevent leaf diseases that develop when foliage stays wet.

When is Parris Island Cos ready to harvest, and what signs should I look for?

Harvest at about 65 days when the plants have formed a firm, well-filled head (or tight rosette for leaf types) with crisp, fully developed outer leaves. Use the “feel test”: gently squeeze the head—if it feels springy and solid rather than loose, it’s ready. Harvest in the morning for best crunch, and cut the head at the base with a clean knife.