Growing Guide to Brussels Sprouts: Plant Care, Varieties, and Tips

Brussels sprouts, with their stalks full of tiny cabbages, can be grown in nearly any USDA Zone. However, the planting time per zone may vary, as may the amount of water it needs and the degree of heat protection you'll need to implement.

But in return for any strategic efforts to grow your own Brussels sprouts, you'll gain a new favorite cold-weather vegetable. Here, we discuss everything you need to know to successfully grow Brussels sprouts.

How to Plant Brussels Sprouts

Timing is crucial when planting Brussels sprouts. Along with being cognizant of seasonal changes, gardeners must keep young starts from succumbing to heat and dryness, and let the “sprouts” get lightly kissed by the cold without them freezing before harvest time. While it may sound like a tall order, don't worry—the process of planting gets easier with practice.

In theory, you could plant them indoors and, if you have a long cool spring, harvest before the weather gets warm. But their flavor and the firmness of the little heads are generally improved by increasingly cold weather.

Growing From Seed

For planting dates, plan backward from when cold weather will keep this cool-weather crop happy, but beware of freezing temperatures. Follow the San Diego Master Gardeners' timeline: Seeds will take 5-8 weeks until they are ready to transplant, and then 90-100 days until harvest. In warm locales, seedlings need shade until they're ready to plant in October or November. 

If you live further north, make sure to plan for a harvest before a deep freeze. You can also try to plant indoors 4-6 weeks before the last frost for an early spring crop.

To start seeds indoors, choose a cool location, and do not use a heat mat. Once the seeds germinate, keep them under a grow light. The University of Minnesota Extension recommends giving seedlings some half-strength starter food and, once the plants have 4-5 true leaves, bringing them outdoors gradually, exposing them to more sunlight and wind each day.

We do not recommend direct seeding because it adds up to three weeks before harvest time. If you do choose this route, plant seeds a quarter- to a half-inch deep and 18 inches apart, water thoroughly, and protect the young plants from wind and pests with a lightweight, securely anchored row cover.

Growing From a Starter and Transplanting

Dig individual holes or a furrow, just deep enough so the plant is at the same level as in its container, and plant the seedlings 18 inches apart. If you are growing multiple rows, they should be about 3 feet apart.

Brussels Sprouts Plant Care

Brussels sprouts are hardy and provide the goodness of leafy greens much further into the colder seasons than most vegetables—yet they have the same plant care requirements and challenges as other cole crops.

Light, Soil, and Nutrients

Brussels sprouts need full sunlight for 6-8 hours, even though they do not like the heat.

Similar to the rest of the cole family, Brussels sprouts should not be planted in the same plot where other relatives have been grown recently. They require crop rotation over a 2-4 years cycle to avoid diseases and pests. Brussels sprouts require well-drained, fertile soil.

Water and Temperature

Brussels sprouts thrive on consistent irrigation or rain to form their tasty mini-cabbages. Frequent watering keeps the plants from becoming too bitter, dry, or poorly formed.

If they don’t get an inch of rain each week, give them a weekly soaking of the same amount (about 5 gallons or two hours). If you grow on drier land or if there is a warm/dry spell while plants are young, you may need to water more than once a week.

Monitor the temperature, as well. If Brussels sprouts grow during weather that is too warm, especially toward harvest time, they will form fluffy tufts of leaves rather than the firm, cabbage-like mini-heads.

Brussels Sprouts Varieties

Like many plants, Brussels sprouts are categorized by their different varieties.

• Jade Cross is compact with bite-sized sprouts. This type is early to mature, meaning that it can be planted a bit later in the fall. It is also heat-tolerant, helping the sprouts form compact heads rather than scruffy bunches of leaves.
• Ruby Crunch, Red Rubine, and Red Bull look like tiny purple cabbages and have the same antioxidants that go along with purple pigments in other foods. Purple varieties tend to be stronger tasting but sweeter.
• Introduced in the 1890s, Long Island Improved is open-pollinated and frost-resistant and is appreciated for its heavy yields.

How to Harvest Brussels Sprouts

Brussels sprout plants will mature about or less than a hundred days after transplanting. To ensure a well-distributed stalk of fairly even-sized sprouts, try trimming lower leaves as the plants grow, and topping off the plants 4-6 weeks before harvesting, when the lower buds are only a half-inch in diameter; this will stop the plant’s vertical growth and redirect its energy to the part we eat.

This step is especially important if you plan to harvest whole stalks. If you are harvesting individual sprouts instead, note that the sprouts mature from the bottom up. Start picking the lower sprouts when they are about one inch in diameter, firm, and vividly colored, whether green or purple.

How to Store and Preserve Brussels Sprouts

Whether on a stalk or as individual “heads”, do not wash or trim the Brussels sprouts. Instead, keep them in a plastic bag or container in your refrigerator's crisper. Eat them as soon as possible after harvest, as their flavor gets more pungent over time.