How to Grow and Care for Brussels Sprouts

Although Brussels sprouts (Brassica oleracea var. gemmifera) date back to ancient Rome, they're named for the city of Brussels, Belgium, where they have been enjoyed for centuries. Part of the cabbage family, Brussels sprouts look like mini cabbage heads. They form on thick stems, along with broad leaves. These leaves are also edible and can be prepared like other hardy greens.

Brussels sprouts are slow-growing biennials (though commonly grown as annuals) that require a long growing season. They are typically planted in the summer for a fall to winter harvest.

How to Plant Brussels Sprouts

When to Plant

Brussels sprouts require a growing season of 80 days or more, and they improve in flavor after being subjected to a light frost. In general, plant seeds approximately four months prior to your area's projected first fall frost date. That likely will mean in the early to mid-summer for areas with cold winters, giving you a fall to early winter harvest. Or in areas with mild winters, you'll typically plant in the mid to late summer for a mid to late winter harvest. 

Selecting a Planting Site

Pick a spot that gets plenty of sun and has sharp soil drainage. A raised garden bed is ideal because it can better withstand temperature fluctuations. Container growth is also an option.

Keep Brussels sprouts away from strawberry plants, as strawberries can inhibit their growth. Likewise, don't place Brussels sprouts by members of the nightshade family, such as tomatoes, as sprouts can affect their growth.

Spacing, Depth, and Support

Plant seeds around a half inch deep and 3 inches apart. Then, seedlings should be thinned to around 18 to 24 inches apart once they reach roughly 6 inches tall. Support stakes are sometimes required to prevent the plants from toppling over as the sprouts develop, and it’s best to add those at the time of planting.

Brussels Sprouts Plant Care

Light

Brussels sprouts perform best in full sun, meaning at least six hours of direct sunlight on most days. Too much shade will slow the sprouts' maturity.

Soil

Brussels sprouts like a loamy, well-drained soil that's rich in organic matter. It's ideal to mix a thick layer of compost into the soil prior to planting. The soil pH should hover around neutral.

Water

Keep the sprouts' soil moist but not soggy. Around 1 to 1.5 inches of water per week should be sufficient. Inconsistent watering can result in poor sprout development. A layer of mulch can help to retain soil moisture and keep the roots cool.

Temperature and Humidity

Brussels sprouts prefer temperatures between 45 and 80 degrees Fahrenheit, though they can tolerate short spells below freezing. Humidity typically isn't an issue as long as their soil moisture needs are met and there's good air flow around the plants.

Fertilizer

Use an organic vegetable fertilizer that’s high in nitrogen starting once the seedlings reach around 6 inches tall. Reapply throughout the growing season, following label instructions.

Pollination

Brussels sprouts flower and go to seed in their second growing season. And because most people grow them as annuals, they don't get to this flowering stage. Insects and the wind assist in their pollination.

Types of Brussels Sprouts

There are several Brussels sprouts varieties that vary in appearance, production, and more:

• 'Jade Cross' is a compact, high-yield plant that's good for windy locations and can withstand some hot weather.
• 'Long Island Improved' is another small but high-yield plant that stands up to wind and tolerates freezing.
• 'Oliver' takes around 80 to 90 days to mature, and it's known for its disease resistance.
• 'Falstaff' features sprouts with a reddish purple color.

Brussels Sprouts vs. Cabbage

Brussels sprouts may look like mini cabbages, and they’re both cool-weather crops. They even have a somewhat similar taste, though cabbage tends to be milder. However, the main difference is Brussels sprouts grow on the plant’s thick stems whereas cabbage heads grow from the ground.

Harvesting Brussels Sprouts

Brussels sprouts grow tall first and don't start producing sprouts until they reach almost full height. Each sprout grows in the leaf axil, or joint. Sprouts begin maturing from the bottom of the plant upward. Start harvesting when the lower sprouts reach about an inch in diameter. Pick them before they get too large and start cracking and turning bitter. Each plant yields approximately a quart of sprouts.

Pulling off the sprouts is easier if you remove the leaf below each sprout first. Then, twist and pull the sprout. Some people prefer to use pruners instead. After harvesting, a second crop of sprouts might begin to grow at the base of the stem. These won't be as tight as the first crop, but they are still edible.

You can store sprouts in the refrigerator for around five days. Don’t wash them until right before you plan to use them. 

How to Grow Brussels Sprouts in Pots

If you don’t have a suitable garden site for a Brussels sprouts plant, container growth can be a good option. It will allow you to control the sunlight, water, and soil for your plant. Opt for a container that’s at least a foot wide and deep. It should have ample drainage holes. Unglazed clay is an ideal material because it will allow excess soil moisture to evaporate through its walls as well.

Pruning

Brussels sprouts generally don’t require pruning. However, you should promptly remove any damaged or diseased portions before they weaken the entire plant. You also can remove yellowed leaves to allow the plant to put its effort into sprout production.

Propagating Brussels Sprouts

Because most people grow Brussels sprouts as annuals, they won’t be able to collect seeds in the plant’s second year for propagation. However, it is possible to regrow Brussels sprouts from scraps. This is an easy way to get more from your harvest, especially if you can’t eat all the sprouts. The best time to start this process is in the early summer for planting outdoors. Here’s how:

1. Wash the sprout, and remove any dead leaves. 
2. Cut the bottom off the sprout. 
3. Position the cut piece with the stem side down so that it’s just submerged in a shallow dish of water. Do not fully submerge the sprout. Place the dish in a warm spot with bright, indirect light.
4. Refresh the water daily. Also, remove any dead leaves.
5. Look for roots forming from the stem in around two weeks. Leaves also will begin to grow from the top. Once there is a substantial root system, the sprout should be ready for transplanting. 

How to Grow Brussels Sprouts From Seed

Brussels sprouts seeds germinate best at temperatures between 45 and 85 degrees Fahrenheit. To start plants in containers, gently press the seeds into a moist seed-starting mix. Keep the soil moist but not soggy, and put the container in a warm spot with bright, indirect light. Expect germination within about three weeks. 

Potting and Repotting Brussels Sprouts

For container growth, use a loose organic vegetable potting mix. If you want, you can mix some compost into the soil to improve its drainage and nutrient content. Repotting shouldn't be necessary, as it's best to select a container that will accommodate the plant's mature size at the time of planting.

Overwintering

Because Brussels sprouts generally are grown as an annual, no overwintering will be necessary. Just make sure to plant early enough for your area to be able to harvest before frigid temperatures set in.

Common Pests and Plant Diseases

Brussels sprouts are prone to the same problems as other plants in the cabbage family. The most common pests are the cabbage looper, cabbageworm, cabbage root maggot, and aphid. Consider using row covers to protect your plants.

Several fungal diseases also can affect Brussels sprouts, including black rot, clubroot, downy mildew, and white mold. Adequate air circulation around the plants can help to prevent fungal issues. If plants become diseased, it’s usually best to destroy them.