How to Grow Long Island Improved Brussels Sprouts
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Long Island Improved Brussels Sprouts
Brassica oleracea var. gemmifera
vegetableLong Island Improved is a classic, heirloom Brussels sprout variety known for producing uniform, compact sprouts on tall stalks. This cool-season crop develops small, cabbage-like heads along the main stem and is prized for its tender texture and mild, slightly sweet flavor when properly grown.
When should you plant Long Island Improved Brussels Sprouts in your zone?
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Example Long Island Improved Brussels Sprouts timeline · Pittsburgh, PA (Zone 6b)
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Plant Long Island Improved Brussels Sprouts
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Long Island Improved Brussels Sprouts
Around Jul 16≈ 90 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Long Island Improved Brussels Sprouts dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-9, with best flavor in cooler climates (zones 5-7)
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Get my Long Island Improved Brussels Sprouts timeline →Growth Stages
Seedling
3-4 weeksTiny, rounded cotyledons emerge and develop true leaves with the characteristic blue-green color of brassicas.
Keep soil moist but not waterlogged. Provide bright light to prevent leggy growth. Maintain temperatures 60-70°F for sturdy seedlings.
Vegetative Growth
6-8 weeksPlant develops a strong central stem with large, lobed leaves. Height increases rapidly; plant becomes bushy with deep green foliage.
Transplant into larger containers or direct seed. Maintain consistent watering and apply balanced fertilizer every 3-4 weeks. Support tall varieties with stakes if needed.
Sprout Formation
4-6 weeksTiny button-like sprouts (0.5-1 inch) begin forming along the stem below leaf axils, starting from the bottom of the plant.
Begin removing lower leaves (only those below forming sprouts) to improve air circulation and direct energy to sprout development. Continue consistent watering and feeding with nitrogen.
Sprout Development & Sizing
3-4 weeksSprouts enlarge to 1-2 inches in diameter, becoming firm and compact. Upper stem may still be growing while lower sprouts mature.
Continue light leaf removal to aid harvest. Reduce nitrogen, increase potassium and phosphorus to promote firm sprout development. Watch for pest damage.
Harvest Ready
2-4 weeks or moreSprouts reach 1-2 inches in diameter, are firm and tightly packed, with deep green color. Lower sprouts are harvestable while upper sprouts continue growing.
Begin harvesting from bottom up as sprouts reach desired size. Harvest before heavy frost for best flavor, though flavor improves after light frost.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Row covers over young plants, hand-picking, Bacillus thuringiensis (Bt), spinosad, or neem oil
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Row covers, hand-picking, Bt sprays, parasitic wasps, neem oil
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Hand-picking, row covers, insecticidal soap, neem oil, yellow sticky traps
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Strong water spray, insecticidal soap, neem oil, ladybugs, row covers on seedlings
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Row covers on seedlings, diatomaceous earth, neem oil, trap crops like radishes
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Yellow sticky traps, strong water spray, insecticidal soap, neem oil, reflective mulch
Uses
Roasted & Sautéed Vegetables
CulinaryLong Island Improved sprouts are excellent roasted whole with olive oil and garlic, or halved and sautéed until caramelized. Their mild flavor makes them versatile for side dishes, pasta, and grain bowls. [source]
Raw in Slaws & Salads
CulinaryShred raw sprouts into coleslaws, salads, or crunch salads where they add a tender, slightly sweet cabbage-like flavor. Excellent in autumn and winter grain salads. [source]
Nutritional & Antioxidant Benefits
MedicinalBrussels sprouts are high in vitamin C, vitamin K, and glucosinolates (compounds with potential cancer-fighting properties). They support bone health, immune function, and contain sulforaphane when lightly cooked. [source]
Cold Storage & Preservation
HouseholdLong Island Improved stores well in cool conditions (32-40°F) for several weeks, or can be blanched and frozen for long-term storage. Ideal for winter preserving and extended harvests. [source]
Pollinator & Beneficial Insect Support
WildlifeAllow some plants to bolt in spring for flowers that attract bees and other pollinators. The tall plants also provide habitat for beneficial predatory insects. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Begin harvesting from the bottom of the plant when sprouts are firm and 1-2 inches in diameter. Twist sprouts gently at the base to remove, or use a sharp knife to cut. Remove the leaf directly above each sprout to encourage upper sprouts to develop. Continue harvesting upward as sprouts mature. Flavor improves after the first light frost. Harvest before temperatures drop below 10°F. Peak harvest is typically October-December in most regions.
Fun Facts
- 🌱 Long Island Improved is an heirloom variety dating back to the 1800s, originally developed in the Long Island region of New York for commercial production and remains a home gardener favorite.
- 🌱 Brussels sprouts actually improve in flavor after exposure to frost; cold temperatures convert starches to sugars, making them noticeably sweeter in fall and winter.
- 🌱 A single Long Island Improved plant can produce 50-100+ sprouts over its harvest season if properly maintained, making it one of the most productive cool-season vegetables per plant.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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