Muir

Lettuce

60d to harvest

Silken, cool-toned leaves unfurl in a graceful Batavian rosette, offering a crisp snap and a refreshingly mild, sweet-green flavor that feels as clean as garden air. Muir’s sturdy heads hold their shape through the season, with a satisfying crunch from tender ribs to ruffled edges—ideal for fresh, leafy salads and vibrant garnishes. Grow Muir for dependable, 60-day harvests and a lush, market-ready presence in the bed.

Crop Dates

Growing note: In frost-free Zone 12a, grow this cool-season crop during the cooler dry season (October–February).

Milestone	Date
Start Indoors	—
Climate	Frost-Free Climate
Transplant / Sow Outdoors	Oct 1st
Harvest Begins	Nov 30th
Harvest Ends	Feb 28th

Crop Details

Trait	Value
Days to Maturity	60
Sun Requirements	Part 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)	5

Frequently Asked Questions

What’s the most common problem on Lactuca sativa (Muir) and how do I stop it?

A frequent issue on lettuce is downy mildew (often appearing as yellow patches on leaves with fuzzy growth on the underside). Improve airflow and avoid wetting the foliage, then remove and discard affected leaves early to slow spread. If it keeps recurring, use an appropriate labeled fungicide for lettuce/downy mildew and stick to a preventive schedule during cool, damp weather.

How often should I water Muir lettuce during active growth, and what soil moisture level should I maintain?

During the main growing phase, keep the bed consistently evenly moist—aim for soil that feels like a wrung-out sponge 1–2 inches down. In typical conditions this is often about 1–2 deep waterings per week, but increase frequency during warm, windy weather to prevent leaf edge browning and bitterness. Avoid letting the soil dry out completely between waterings, because lettuce of Asteraceae type can turn stressed and bolt faster.

How can I tell when Muir (Lactuca sativa) is ready to harvest?

Harvest when heads/rosettes are firm and sized for the variety, typically around 60 days from sowing as a guide for Muir. Check the outer leaves: they should be fully expanded and crisp, not limp, and the plant should hold its shape with minimal give when gently pressed. If you see a tall central seed stalk forming, harvest immediately to get usable leaves before quality declines.