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 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 better withstands temperature fluctuations. Container growth is also an option.

Keep Brussels sprouts away from strawberry plants, as strawberries inhibit their growth.Likewise, don't place Brussels sprouts near members of the nightshade family, such as tomatoes, as they affect each other's 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 results in poor sprout development. A layer of mulch helps to retain soil moisture and keep the roots cool.

Temperature and Humidity

Brussels sprouts do best when daytime temperatures do not exceed 70°F. or less. The plants thrive in cool, wet weather and tolerate a light frost, which improves their taste. Extended temperatures below freezing, on the other hand, damage the plants. In USDA Zones 7 and higher, Brussels sprouts make an excellent winter crop.

Humidity typically isn't an issue as long as there's good airflow 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

If you grow Brussels sprouts as an annual because you only want to harvest the sprouts, no pollination is needed. But if you intend to collect the seeds, you will need at least two plants of an open-pollinated variety (not a hybrid). In their second year, the plants will flower and, after being pollinated by insects, produce seeds which you can collect for propagation.

Types of Brussels Sprouts

There are many different varieties of Brussels sprouts. They differ in plant size, sprout size and color, yield, days to maturity, and disease resistance. Popular varieties include:

• 'Jade Cross' is a compact, high-yield hybrid variety good for windy locations. It is more heat-tolerant than some other varieties. 87-100 days to maturity.
• 'Long Island Improved' is an open-pollinated heirloom variety. The plant is small but produces high yields. It withstands wind and tolerates freezing. 80-115 days to maturity.
• 'Oliver' has large, tight, bright-green sprouts that are well-spaced on the stem. This hybrid is known for its disease resistance. 90-100 days to maturity.
• 'Falstaff' features sprouts with a reddish-purple color, which also makes it attractive as an ornamental plant. 98 days to maturity.

Brussels Sprouts vs. Cabbage

Brussels sprouts 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 is 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. Removing yellowed leaves allows 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°F. 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. 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.

Tip

To protect Brussels sprouts against pests, use a fabric row cover while the plants are young, which is when they are the most vulnerable. To protect taller plants, create a low tunnel using hoops covered with row covers. You can find corrosion-resistant galvanized steel wire hoops at garden supply stores.

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

From: thespruce