Long Island Improved Brussel Sprout Seeds. Said to have originated in Brussels Belgium, Brussels Sprouts have been a staple vegetable since the 1890's. Long Island Improved is the widely consumed and grown. Requires attentive care. Roots are shallow, so, add mulch for protection. Will tolerate frost. Requires full sun exposure. Height - 24 inches, Spacing - 16 to 18 inches, Planting Depth - 1/4 inch, Root Depth - 18 to 36 inches. Harvest from the bottom of the stalk and move your way up. Store in cool dark places for optimal longevity. Contains essential nutrients such as calcium, iron, vitamins A and C.