Red Leaf Lettuce
Lactuca sativa var. crispa
Family: Asteraceae
Red leaf lettuce features loose, frilly leaves with beautiful burgundy and bronze coloring. The tender leaves have a mild, slightly sweet flavor with just a hint of bitterness. Fast-growing and productive, it adds color and nutrition to any salad.
Days to Harvest
45-55 days
Sun Needs
Full Sun to Partial Shade (4-6 hours)
moderate
Germination Temp
65°F optimal
Start Indoors
4 weeks before last frost
Germination
2-10 days
Seed Depth
1/8 inch
Light to Germinate
Yes
💡 Tip: Seeds need light to germinate. Press into soil surface and barely cover. Develops best red color with some sun exposure.
Soil Type
Rich, well-draining soil with good organic matter
pH Range
6 - 7
Spacing
6-8 inches between plants, 12 inches between rows
⚠️ Avoid planting near:
History
Loose-leaf lettuces have been cultivated since ancient times, with colored varieties developed through selective breeding over centuries. Red-pigmented lettuces became popular in European gardens by the 1600s and are now standard in mesclun mixes worldwide.
Nutritional Benefits
- ✓High in Vitamin K
- ✓Good source of Vitamin A
- ✓Contains anthocyanins (red pigments with antioxidant properties)
Optimal Growing Temp
60°F - 70°F
Red leaf lettuce thrives in cool temperatures between 60-70°F. The red coloring develops best with moderate temperatures and adequate sunlight. Heat above 75°F can cause bolting and reduce pigment development.
Survival Range
35°F - 80°F
Can survive these temperatures
Frost Note: Red leaf lettuce tolerates light frost (28-32°F) and can handle brief exposure to temperatures in the mid-20s with protection. Cold temperatures actually intensify the red coloring.
Best USDA Zones
Humidity
40-60%
Moderate humidity is best. High humidity promotes fungal diseases like downy mildew which can spread quickly through red leaf varieties.
Height
8-12 inches
Spread
8-10 inches
Growth Habit
upright
Germination
2-10 days
Seeds germinate quickly, needing light. Green cotyledons emerge first, red color develops later.
Seedling Stage
Duration: 2-3 weeks
True leaves: First true leaves appear with slight red tinge. Color intensifies with growth and sun exposure.
Transplant ready: Ready when 2-3 inches tall with 3-4 true leaves showing red coloration.
Vegetative Growth
Duration: 3-4 weeks
Rapid leaf production with deepening red coloration. Harvest outer leaves as needed.
Harvest Maturity
Timing: 45-55 days from seed
- Full head development with characteristic red coloring
- Harvest before any sign of bolting
Per Plant
4-8 oz of leaves per plant
Per Square Foot
6-8 oz when planted at 6-inch spacing
Harvest Frequency
Cut-and-come-again every 5-7 days, or harvest whole head at maturity
Factors Affecting Yield
- •Sunlight exposure for red color
- •Temperature consistency
- •Harvest timing
- •Succession planting
Seedling Stage
Daily light watering to keep surface moist
Established Plants
Every 2-3 days, or when top inch of soil dries
Preferred Method
Water at soil level using drip irrigation or soaker hose. Avoid wetting leaves to prevent disease.
⚠️ Critical Watering Periods
- • During germination for establishment
- • Hot weather to prevent bolting
Pro Tips
- Consistent moisture is key for tender leaves and good color
- Morning watering is best to allow leaves to dry before evening
- Mulch to retain soil moisture and keep roots cool
- Water stress causes bitterness and poor color development
Feeding Schedule
Organic Options
Top-dress with thin layer of compost or apply diluted liquid feed every 3-4 weeks if needed
Minimum Size
6 inch pot minimum
Recommended Size
8-10 inch pot or window box
Depth Required
6-8 inches minimum
Best Varieties for Containers
Container Tips
- Red leaf lettuce is excellent for containers and window boxes
- Use light-colored containers to keep roots cool
- Position for morning sun, afternoon shade in warm weather
- Ensure adequate drainage to prevent root rot
- Group containers together to retain moisture
Why Prune
When
Harvest outer leaves when 4-6 inches long
How Often
Every 5-7 days for cut-and-come-again harvest
Technique
Cut or snap outer leaves at base, leaving center growing point intact for continued production
Remove
- ✗ Outer mature leaves
- ✗ Yellowing or damaged leaves
- ✗ Any leaves touching soil
Keep
- ✓ Center growing point
- ✓ Inner developing leaves
- ✓ At least 4-5 inner leaves
Plant Every
2-3 weeks
Sowings/Season
4-6 sowings per growing season
Duration
Spring through early summer, then resume late summer through fall
Tips
- Start succession planting 4-6 weeks before last frost
- Take a break during hottest summer months
- Resume planting 8-10 weeks before first fall frost
- Overlap plantings so new plants mature as older ones bolt
