- Name: Heirloom Brussel Sprouts - Other Common Names: Long Island Brussel Sprouts - Scientific Name: Brassica Oleracea - Color: Dark Green - Plant Seeds: Outdoors After Frost / Indoors Weeks Before Last Frost - Harvest: 90 Days - Hardiness Zone: Annual - Plant Height: 24 - 36" - Plant Spacing: 15 - 18" - Light Requirements: Sun - Soil & Water Preferences: Average - Quantity: 500 Seeds - Other: ‘Long Island Improved’ Is A Popular Heirloom Variety Brussel Sprout. It Is A Very Vigorous Grower And Is Extremely Cold Hardy. The Plants Are Not Affected By Frost, And Somewhat Surprisingly, Frost Enhances The Flavor. These Compact Plants Yield Between 50-100 Dark Green Tight Sprouts That Are About 1 ½” Around.