Long Island Improved Brussels Sprouts stand as a testament to American gardening heritage, representing one of the oldest and most beloved Brussels sprouts varieties still grown today. These sturdy plants mature into impressive 48-inch stalks that produce firm, cabbage-like sprouts over 100 days in zones 4-8. Sometimes confused with the newer Catskill strain, Long Island Improved predates it by decades and remains the most popular variety for good reason. With their remarkable cold tolerance and ability to sweeten after frost, these sprouts transform winter gardens into productive landscapes when most other crops have finished.
Photo © True Leaf Market
Growing Conditions
USDA Zone
4-8
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained, Fertile Loam With Consistent Moisture
Preferred Temp60-75°F
Growth Stats
24 in
Height
18 in
Width
24 in
Spacing
85–110
Days to Harvest
PeriodBiennial
TypeBush
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
4-8
Size
24in H x 18in W
Growth
Biennial
Care
High
Hover over chart points for details
Highlights
What sets Long Island Improved apart is its proven reliability across generations of American gardeners and its exceptional cold hardiness that actually improves flavor quality. These robust plants reach an impressive 4 feet tall without requiring staking, creating dramatic garden architecture while producing abundant harvests. The variety's ability to withstand harsh frosts and continue producing through late fall makes it invaluable for extending the growing season. Its historical significance as the foundation variety that established Brussels sprouts cultivation in America adds meaningful depth to every harvest.
Common Uses
These Brussels sprouts excel in traditional fall and winter cooking preparations, where their strong, slightly bitter flavor similar to cabbage shines in roasted dishes, braised preparations, and hearty stews. The firm, compact sprouts hold their shape well when cooked and develop a sweet, nutty character after exposure to frost. Their robust flavor makes them ideal for pairing with rich ingredients like bacon, butter, and nuts, while their cold-weather harvest timing makes them perfect for holiday meals and winter comfort foods.
Growing Timeline
First Bloom
Not Applicable
First Harvest
Mid-fall
Last Harvest
Early Winter
Care Instructions
Start Indoors
Start seeds indoors 4-6 weeks before transplanting, approximately 4 months before your average first fall frost date. Sow 2-3 seeds per cell at 1/2 inch deep in soil temperatures between 60-85°F for optimal germination. Thin to the strongest seedling per cell once sprouted.
Transplant Outdoors
Transplant outdoors when seedlings develop 2 sets of true leaves, spacing them 24 inches apart. Ensure soil temperature is at least 40°F and plan timing so sprouts mature during cool fall weather.
Direct Sow
Direct sow 4 months before average first fall frost when soil temperature reaches at least 40°F, though starting indoors is recommended for best results.
Harvesting
Harvest sprouts when they become firm and reach 1-2 inches in diameter, typically 90-100 days from transplant. Individual sprouts mature from bottom to top, so harvest the lowest sprouts first by twisting them until they separate from the stalk or cutting with a knife. For uniform harvest timing, cut off the plant's growing tip 3 weeks before desired harvest date to force simultaneous maturation. Entire stalks can be harvested by cutting the plant at the base once all sprouts are firm.
Pruning
As Brussels sprouts develop along the stalk, regularly remove yellowing and lower leaves to direct the plant's energy into sprout production. This pruning also improves air circulation and reduces disease risk around the developing sprouts.
Growing Calendar
Enter your ZIP code to see a personalized growing calendar for this plant.
Companion Planting
Ecology & Traits
Edible
Scientific Classification
Brassica oleracea L. var. gemmifera DC.
Family
Brassicaceae
Genus
Brassica
Duration
Biennial
Growth Habit
Upright
Native Status
L48 (I)PR (I)CAN (W)GL (W)
History & Origin
“Long Island Improved represents one of America's most enduring Brussels sprouts varieties, predating the similar Catskill strain developed by Arthur White of Arkport, New York in 1941 by several decades. While the two varieties are often confused due to their similarities, Long Island Improved established itself as the standard by which other Brussels sprouts varieties are measured. This heirloom variety became the foundation for Brussels sprouts cultivation across American gardens, maintaining its popularity even as newer varieties emerged. Its longevity speaks to the careful selection and preservation work of early American gardeners who recognized and maintained its superior qualities.”