One of the most unusual members of the cabbage family, Brussels sprout plants develop miniature cabbage heads along the main stem, starting from the bottom up. Sprout formation does not begin until the plants are mature, which can occur 90 to 120 days after transplanting, depending on variety and weather conditions.
Exposure to frost improves the flavor of Brussels sprouts, so they are a yearly treat of early winter. Where winters are mild, Brussels sprouts can be grown through winter for harvest in early spring.
Types of Brussels Sprouts
Brussels sprout varieties vary in growth rate, productivity and color. Hybrids including ‘Diablo’ and ‘Dimitri’ have been the most productive in field trials in a variety of locations. Where these reliable varieties do well, you can also try heirlooms such as ‘Long Island’ or red ‘Rubine.’
Days to maturity ratings for Brussels sprout varieties range between 90 and 120 days, with most varieties falling in between. However, this estimate represents the date of your first picking only. Brussels sprout plants that start producing about two weeks before your last frost date will bear good crops over a long season. When growing Brussels sprouts, expect weekly harvests of four to five sprouts per plant for about six weeks.
How to Plant Brussels Sprouts
Unlike cabbage and broccoli, growing Brussels sprouts is seldom successful from plants set out in spring. Hot weather that arrives just as spring-planted sprouts start sprouting ruins their flavor and texture, and the plants become magnets for insects.
It is much better to wait until late spring or early summer to start Brussels sprout seeds. Recommended seeding dates for a few locations include March 30 in Rhode Island, May 15 in New York, June 5 in West Virginia, and July 1 in Alabama. Harden off the seedlings before setting them out in well-prepared soil, and plan to cover them with lightweight row cover or tulle to exclude insect pests.
Brussels sprouts are heavy feeders that demand moist, fertile soil with a pH between 6.0 and 7.0. The ideal soil texture for Brussels sprouts is clay, because tight clay helps hold the roots firm when the large plants are blown by harsh winds. Mix in a generous application of a balanced organic fertilizer before planting, and use a biodegradable mulch of grass clippings or coarse compost to insulate the roots from summer’s heat.
For recommended planting dates for your local climate — and to design your garden beds — try our Vegetable Garden Planner.
Growing Brussels Sprouts
Featherweight row cover held aloft with hoops or stakes is the easiest way to protect Brussels sprout plants from grasshoppers and other summer insects. When the plants are 12 inches tall, top-dress them with a high nitrogen organic fertilizer such as composted manure.
As plants grow, stake plants to keep them from falling over. Upright Brussels sprout plants produce better than crooked ones.
Harvesting and Storing Brussels Sprouts
To harvest, twist off sprouts, a few at a time, as soon as they are at least one-half inch in diameter. Keep in mind that the first sprouts are often much smaller than those produced later in the season. Breaking off the lowest leaves gives nearby sprouts more room to grow.
Refrigerate harvested sprouts immediately. Brussels sprouts will keep in the refrigerator for several weeks, or they can be blanched and frozen. Here’s another neat storage option: In the North where the plants grow quite large, they can be pulled from the garden with sprouts still attached, stripped of their leaves, and stuck into a bucket of damp sand kept in a cold root cellar.
Propagating Brussels Sprouts
As biennials, Brussels sprouts produce yellow flowers followed by elongated seedpods in their second year. When the seedpods dry to tan, gather them in a paper bag, and allow them to dry indoors for a week. Shatter the dry pods and collect the largest seeds for replanting. Under good conditions, Brussels sprouts seeds will store up to three years.
(For details on growing many other vegetables and fruits, visit our Crop at a Glance collection page.)
Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens.