Growing Brussels Sprouts
The American public seems to have a love-hate relationship with Brussel Sprouts. Personally I love these tiny, little cabbages; especially lightly steamed with a little butter and salt. However, they can be a little tricky to grow in the home vegetable garden.
Brussel sprouts are grown for fall harvest because cool weather during maturity is essential for good flavor and quality. They are tall, erect biennials grown as annuals, and range in size from 14 inches to 3 feet. The sprouts develop in the leaf axils and mature along the stalk. The lowest sprouts mature first and should be harvested when firm and 1-2 inches in diameter. The lowest leaves may be removed to permit sprouts to mature. Cultivars recommended for Nebraska include ‘Prince Marvel', ‘Jade Cross' and ‘Bubbles'.
Brussel sprouts prefer full sun and a well-drained soil, high in organic matter, with a pH from 5.5 to 6.5. They require 80-100 days from seed to harvest, and should be directly seeded into the garden in early to mid-summer. The plants should be seeded 12-18 inches apart within the rows, with 24-30 inches between rows. Plant the seed shallowly, ¼ - ½ inch deep, in a continuous row, then after germination thin plants to the desired spacing. Use close spacing to produce smaller sprouts of a more uniform size, and a wider spacing for large sprouts that mature in succession so they may be picked over a longer period. Brussel sprouts are heavy feeders that will require fertilization to produce well. Sidedress plants with 1 tablespoon of ammonium nitrate per 20 feet of row, two to four weeks after planting or when the plant reach 12 inches high. With their slow rate of growth, Brussel sprouts may be interplanted with another fast maturing crop during the first few weeks of growth.
A common problem experience by home gardeners growing Brussel sprouts, are heads with loose tufts of leaves instead of firm heads. Caused by high temperatures as the sprouts are maturing, correct this by planting later in the season so the heads mature during cool temperatures. Ground that has been freshly amended with manure before planting can also cause loose, rather than firm sprouts. Imported cabbageworm, cabbage looper, cutworms, flea beetles, mealybugs and aphids can all be a problem for Brussel sprouts. Row covers can protect your plants from all of these insects, since Brussel sprouts do not required pollination to develop.
The sprouts are ready to harvest when the heads are hard, compact, deep green and about 1-1 ½ inches in diameter. Leave them in the garden until after a killing frost to improve the flavor. Twist or snap the heads off the stalks, and harvest the lowest heads first. If the sprouts are intended for freezing, pick them before the outer leaves are damaged. Freeze only top quality sprouts. The hardiest Brussel sprout cultivars can survive temperatures of -10° F, but if cold weather approaches before the sprouts have been harvested, uproot whole plants before the ground freezes and hang them in a cool, frost-free place; the sprouts will remain fresh for several weeks.