Great Lakes 659

Lettuce

70d to harvest

Cool, crisp perfection begins with Great Lakes 659—an elegant crisphead forming tight, uniform heads that feel satisfyingly dense and snap with a clean, watery crunch. The flavor is fresh and gently sweet, with a pale, buttery interior and crisp outer leaves that hold their structure beautifully in the garden. Grow it for classic crisphead salads and refreshing wedges, and enjoy its dependable, market-ready texture at maturity in about 70 days.

Crop Dates

Milestone	Date
Start Indoors	May 4th
Last Frost	May 25th
Transplant / Sow Outdoors	May 25th
Harvest Begins	Aug 3rd
Harvest Ends	Aug 29th

Crop Details

Trait	Value
Days to Maturity	70
Sun Requirements	Full Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Surface
Germination Temp (°F)	55
Min Soil Temp (°F)	40
Min Night Temp (°F)	32
Harden Off (days)	5

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Frequently Asked Questions

What pest or disease is most common on Lactuca sativa (leaf lettuce), and how can I control it?

Lettuce commonly gets downy mildew and aphids (often together on cool, humid days). For downy mildew, remove affected leaves, improve airflow, and avoid wetting the foliage; if it keeps spreading, use a labeled fungicide suitable for lettuce. For aphids, blast plants with a strong water spray and then spot-treat with insecticidal soap if colonies persist—don’t wait because aphids multiply quickly on lettuce.

How do I tell when Lactuca sativa 'Great Lakes 659' is ready to harvest?

Harvest when heads (or leaf clusters, depending on how you’re growing it) reach the expected mature size and the leaves feel firm rather than limp. Look for maturity around 70 days from sowing and harvest on a cool morning before heat makes the leaves tougher. If you see the center starting to bolt (rapid vertical growth and flower stem forming), harvest immediately to get the best flavor.