Green Gem

Family: Asteraceae Vegetable

Planting Schedule

Provide your location or planting zone to unlock dates and add Green Gem to a garden.

Cool, crisp hearts emerge in a vivid Green Gem—tender, sweet-leaning leaves with a clean, refreshing crunch and a beautifully upright romaine form.

At maturity in about 55 days, the foliage forms tight, elongated heads with a smooth, slightly glossy surface and a gently ribbed texture that stays crisp in the garden. Ideal for fresh salads and vibrant sandwiches, Green Gem also shines in quick tosses and bright, leaf-forward platters where its sturdy structure holds up with grace.

Light: Part SunMaturity: 55 DaysHabit: Rosette

Location not set yet

Enter your ZIP for local crop dates

Green Gem Planting Dates by USDA Zone

Estimated US hardiness-zone windows for sow, transplant, and harvest. Enter a US ZIP above for exact local dates, or open a zone below.

Zone	Start Indoors	Sow / Transplant	Harvest
Zone 1a	Protected Environment Only
Zone 1b	May 4th	Jun 1st	Jul 26th – Aug 1st
Zone 2a	Apr 27th	May 25th	Jul 19th – Aug 29th
Zone 2b	Apr 17th	May 15th	Jul 9th – Aug 25th
Zone 3a	Apr 17th	May 15th	Jul 9th – Sep 1st
Zone 3b	Apr 21st	May 19th	Jul 13th – Sep 21st
Zone 4a	Apr 17th	May 15th	Jul 9th – Sep 24th
Zone 4b	Apr 15th	May 13th	Jul 7th – Sep 27th
Zone 5a	Apr 10th	May 8th	Jul 2nd – Sep 30th
Zone 5b	Apr 6th	May 4th	Jun 28th – Oct 5th
Zone 6a	Apr 3rd	May 1st	Jun 25th – Oct 10th
Zone 6b	Mar 28th	Apr 25th	Jun 19th – Oct 16th
Zone 7a	Mar 23rd	Apr 20th	Jun 14th – Oct 20th
Zone 7b	Mar 13th	Apr 10th	Jun 4th – Oct 28th
Zone 8a	Mar 4th	Apr 1st	May 26th – Nov 5th
Zone 8b	Feb 23rd	Mar 23rd	May 17th – Nov 12th
Zone 9a	Feb 6th	Mar 6th	Apr 30th – Nov 26th
Zone 9b	Jan 12th	Feb 9th	Apr 5th – Dec 9th
Zone 10a	—	Oct 1st	Nov 25th – Feb 28th
Zone 10b	—	Oct 1st	Nov 25th – Feb 28th
Zone 11a	—	Oct 1st	Nov 25th – Feb 28th
Zone 11b	—	Oct 1st	Nov 25th – Feb 28th
Zone 12a	—	Oct 1st	Nov 25th – Feb 28th
Zone 12b	—	Oct 1st	Nov 25th – Feb 28th
Zone 13a	—	Oct 1st	Nov 25th – Feb 28th
Zone 13b	—	Oct 1st	Nov 25th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	55
Sun Requirements	Part Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Surface
Germination Temp (°F)	40
Min Soil Temp (°F)	40
Min Night Temp (°F)	35
Harden Off (days)	6

Culinary Notes

Chef's Note

Green Gem’s tight, upright romaine form and sweet-leaning, lightly juicy bite make it a salad and sandwich workhorse—it resists collapsing and stays crisp even after dressing. Use it in anything where you want structure on the fork, not wilting into the bowl.

Best Uses

romaine-style wedge salads with a creamy dressing that clings to ribs
crisp sandwich crunch where the leaf holds shape instead of going limp
quick toss salads where it stays snappy under a light vinaigrette
leaf-forward platters—drizzled, dressed, and served immediately for maximum bite

Flavor Profile

tender sweet-leaning greens clean, refreshing crunch gently ribbed, lightly juicy bite

Kitchen Pairings

lemon vinaigrette Parmesan Caesar dressing garlic-rubbed croutons grilled chicken

Frequently Asked Questions

What pest or disease most often affects Lactuca sativa (lettuce), and how do I control it?

For lettuce, aphids and downy mildew are common. Spray aphids off with a strong jet of water and, if needed, use an insecticidal soap, targeting the undersides of leaves; remove heavily infected leaves to slow down downy mildew. Keep soil off the lower leaves by avoiding overhead watering and spacing plants so leaves dry quickly after rain or irrigation.

How often should I water Lactuca sativa during the main growing phase?

During active leaf growth, keep the top 1–2 in (2.5–5 cm) of soil evenly moist but not waterlogged to prevent tip burn and bitterness. In most home gardens this works out to about 1 in (2.5 cm) of water per week, adjusted so the soil never dries out fully between waterings. Water early in the day and focus on the soil line to avoid wet foliage.

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

Harvest when heads are firm and have reached the variety’s typical size at about 55 days, and leaves feel crisp rather than limp. For loose-leaf lettuce, you can also do a cut-and-come-again harvest, taking outer leaves once they’re large enough to eat. If you see the center starting to bolt (rapid stem growth), harvest immediately to avoid tough, bitter leaves.