Muir
Lactuca sativa
The slowest to bolt in our summer trials. Technically a Batavian type, the light green extra-wavy leaves form dense heads at a small size and can be harvested as a mini or left to bulk up into large, heavy, full-size heads. The leaves are crisp and have excellent flavor. Suitable for hydroponic systems. Utility Patent granted. MT0-30. Also available with NOP-compliant pelleting.
Harvest
50d
Days to harvest
Sun
Full sun to partial shade
Zones
2–11
USDA hardiness
Height
6-12 inches
Planting Timeline
Showing dates for Muir in USDA Zone 7
All Zone 7 lettuce →Zone Map
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Muir · Zones 2–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | — | — | May – June | July – October |
| Zone 4 | — | — | April – June | July – October |
| Zone 5 | — | — | April – May | June – November |
| Zone 6 | — | — | April – May | June – November |
| Zone 7 | — | — | March – May | May – November |
| Zone 8 | — | — | March – April | May – December |
| Zone 9 | — | — | February – March | April – December |
| Zone 10 | — | — | January – March | March – December |
| Zone 1 | — | — | June – July | July – September |
| Zone 2 | — | — | May – July | July – September |
| Zone 11 | — | — | January – February | February – December |
| Zone 12 | — | — | January – February | February – December |
| Zone 13 | — | — | January – February | February – December |
Succession Planting
Direct sow Muir every 14 days starting around March 1 in zone 7, and keep going through mid-April. At 50 days to harvest, that spacing gives you a fresh cutting roughly every two weeks from May into early June. Stop sowing once daytime highs are consistently hitting 80°F — germination rates drop above that threshold and plants that do establish will bolt before they're worth cutting.
Pick back up with another round of sowings in late August (around August 20–September 1 in zone 7), when soil temps start dropping back below 75°F. Fall lettuce often outperforms spring — fewer pest and disease problems, slower bolting, and the heads tend to be crisper. Push that fall succession into early October if you have row cover ready for any frost below 28°F.
Complete Growing Guide
The slowest to bolt in our summer trials. Technically a Batavian type, the light green extra-wavy leaves form dense heads at a small size and can be harvested as a mini or left to bulk up into large, heavy, full-size heads. The leaves are crisp and have excellent flavor. Suitable for hydroponic systems. Utility Patent granted. MT0-30. Also available with NOP-compliant pelleting. According to Johnny's Selected Seeds, Muir is 50 days to maturity, annual, open pollinated. Disease resistance includes Downy Mildew, Lettuce Leaf Aphid Nasonovia ribisnigri, Tomato Bushy Stunt Virus, Lettuce Mosaic Virus.
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: High Organic Matter. Soil pH: Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 0 ft. 6 in. - 1 ft. 0 in. Spread: 0 ft. 6 in. - 1 ft. 0 in. Spacing: Less than 12 inches. Growth rate: Rapid. Maintenance: Medium. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.
Harvesting
Muir reaches harvest at 50 days from sowing per Johnny's Selected Seeds. As an annual, harvest continues until frost ends the season.
Tiny seeds with a dandelion-like tuft (pappus) to aid in wind dispersal.
Color: Brown/Copper. Type: Achene. Length: < 1 inch. Width: < 1 inch.
Harvest time: Summer
Edibility: Leaves can be used raw or cooked in salads, sandwiches, and other dishes. Head lettuce can be stored for 2-3 weeks while leaf and butterhead store for 1-2 weeks.
Storage & Preservation
Store freshly harvested Muir lettuce immediately in the refrigerator crisper drawer at 32-35°F with high humidity. Wrap loose heads in damp paper towels, then place in perforated plastic bags to maintain moisture while allowing air circulation. Properly stored heads maintain quality for 7-10 days, significantly longer than most butterhead varieties.
For best texture, avoid washing until ready to use, as excess moisture accelerates decay. If leaves begin wilting, revive them by soaking in ice water for 10-15 minutes before serving.
While lettuce doesn't preserve well through traditional methods, you can freeze Muir for cooked applications like soups or stir-fries by blanching whole leaves for 30 seconds, shocking in ice water, and freezing in portions. The tender leaves also work well in green smoothies when frozen. Dehydrating isn't recommended due to the high water content and delicate leaf structure.
History & Origin
Muir is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.
Origin: Mediterranean to Siberia
Advantages
- +Exceptionally slow to bolt, extending harvest window during hot summers
- +Versatile sizing allows mini harvests or full-size head production
- +Crisp leaves with sweet, buttery flavor and delicate texture
- +Works well in hydroponic systems for controlled environment farming
- +Patented variety with organic certification and pelleting options available
Considerations
- -Moderate difficulty requires attention to growing conditions and timing
- -Susceptible to multiple pests including aphids, thrips, and leafminers
- -Vulnerable to downy mildew and lettuce drop fungal diseases
- -Prone to tip burn when calcium uptake or humidity management is poor
Companion Plants
Radishes and carrots are probably the most practical companions for Muir. Radishes germinate in 5–7 days and mark the row while the lettuce is still getting established — pull them at 25–30 days and you've loosened the top few inches of soil right next to your lettuce roots without disturbing anything. Carrots don't compete hard for water at the same depth, so the 1–1.5 inches per week you're already giving the lettuce suits them both. Chives and garlic planted along the bed edges produce sulfur compounds that aphids and thrips find off-putting, which matters because both pests hit lettuce regularly once populations build.
Fennel is the one to put somewhere else entirely — its roots release allelopathic compounds that genuinely suppress nearby plants, and lettuce is sensitive to them. Broccoli pulls nitrogen aggressively from the same soil zone as lettuce roots, and its canopy throws more shade than you'd expect once it sizes up — a 12-inch broccoli head can cut light to an 8-inch lettuce plant faster than you'd think. Keep those two at least a full bed away.
Plant Together
Basil
Repels aphids and whiteflies, may improve lettuce flavor
Chives
Repels aphids and other pests while taking up minimal space
Carrots
Helps loosen soil for lettuce roots and doesn't compete for nutrients
Radishes
Quick-growing companion that helps break up soil and deters pests
Marigolds
Natural pest deterrent, repels aphids and nematodes
Spinach
Similar growing requirements and can be succession planted together
Garlic
Natural fungicide properties and aphid deterrent
Nasturtiums
Acts as trap crop for aphids and adds beneficial insects
Parsley
Attracts beneficial insects and doesn't compete aggressively
Keep Apart
Broccoli
Large leaves create excessive shade and compete for nutrients
Fennel
Allelopathic properties inhibit growth of lettuce and most vegetables
Sunflowers
Allelopathic compounds in roots can stunt lettuce growth
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #2346388)
Pests & Disease Resistance
Resistance
Downy Mildew (EU) races 16-26, 28, 32 (High); Downy Mildew (US) races 5-9 (High); Lettuce Leaf Aphid Nasonovia ribisnigri (High); Lettuce Mosaic Virus (Intermediate); Tomato Bushy Stunt Virus (High)
Common Pests
Aphids, thrips, leafminers, slugs
Diseases
Downy mildew, lettuce drop, tip burn
Troubleshooting Muir
What you'll see, why it happens, and what to do about it.
Seedlings collapsing at the soil line within the first 7–10 days after planting — stems look pinched or water-soaked at the base
Likely Causes
- Damping off — a complex of soil-borne fungi (Pythium spp., Rhizoctonia solani) that thrive in cool, wet, poorly drained soil
- Replanting in the same bed where lettuce has grown for 2+ consecutive years, which allows pathogens to build up
What to Do
- 1.Use fresh, sterile seed-starting medium every time — reused mix carries the fungi that cause this
- 2.Let the soil surface dry slightly between waterings once seeds are in; consistently saturated conditions are exactly what Pythium needs to spread
- 3.If you've lost seedlings in the same bed multiple years running, rotate that bed out of lettuce for at least one full season and improve drainage before replanting
Gray-purple fuzzy coating on the undersides of leaves, with yellow patches on the upper surface — usually appears in cool, wet weather
Likely Causes
- Downy mildew (Bremia lactucae) — spreads rapidly when nights are cool (below 65°F) and humidity is high
- Crowded spacing that traps moisture between plants
What to Do
- 1.Space Muir at least 8 inches apart — 10–12 inches is better — so air can move through the canopy
- 2.Water at the base, not overhead, and water in the morning so foliage dries before nightfall
- 3.Remove and bag (don't compost) any heavily infected leaves; if the whole planting is gone, pull it and wait for drier conditions before resowing
Brown, papery edges on the innermost or youngest leaves — outer leaves look fine
Likely Causes
- Tip burn — a calcium distribution problem triggered by rapid growth during warm spells, not a soil calcium deficiency
- Uneven watering that interrupts the transpiration stream carrying calcium to the leaf margins
What to Do
- 1.Keep soil moisture steady at 1–1.5 inches per week; the swings between dry and saturated are what cause tip burn more than anything else
- 2.Harvest promptly at 50 days — heads left to bulk up in warm weather are more prone to tip burn than those cut on schedule
- 3.If tip burn keeps coming back in a particular bed, check that soil pH sits between 6.2 and 6.8; calcium uptake slows down outside that range
Ragged holes in leaves with slime trails visible in the morning — damage worst at the base of the plant and on lower leaves
Likely Causes
- Slugs (Deroceras reticulatum and related species) — active at night and in wet weather, hiding under mulch and debris during the day
- Overly thick mulch pushed right up against the stems, which gives slugs a cool, damp refuge a few inches from your plants
What to Do
- 1.Pull mulch back 2–3 inches from the base of each plant to cut off the main hiding spots
- 2.Set out shallow traps — a tuna can sunk to soil level and filled with beer — check and empty every morning
- 3.Iron phosphate bait (Sluggo and similar products) is effective and safe around edibles; scatter it in the evening when slugs are moving
Frequently Asked Questions
How long does Muir lettuce take to grow from seed?▼
Can you grow Muir lettuce in summer heat?▼
Is Muir lettuce good for container growing?▼
What does Muir lettuce taste like compared to other varieties?▼
When should I plant Muir lettuce for summer harvest?▼
Why is my Muir lettuce developing tip burn?▼
Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
- USDAUSDA FoodData Central
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.