How to Plant and Grow Brussels Sprouts
Learn how to plant and grow Brussels sprouts, enjoyed for their tenderness and nutty flavor.
Here’s a reason (or three) to love Brussels sprouts just in case the earthy, mustardy flavor hasn’t convinced you yet. In addition to 96mg vitamin C in a single cup serving, this cruciferous vegetable also provides detoxification and antioxidant support, benefiting both the digestive and cardiovascular systems and reducing overall inflammation, which may help reduce the risk of certain cancers, according to the Linus Pauling Institute.
Let’s be honest — not many folks get excited about dishes prepared with Brussels sprouts. That is, unless the sprouts are soaked in melted butter or smothered with cheese. But the truth is that Brussels sprouts harvested fresh from the garden can be tender, a little nutty, sweet, and so delicious with minimal culinary preparation. If you’re not a fan of Brussels sprouts, give them another chance and a little room to grow in your garden, and you may just change your mind.
Choosing Which Brussels Sprouts to Grow
The first step in growing Brussels sprouts is to decide which variety you’d like to plant. Look for disease-free seeds and disease resistant varieties. If you live in an area with long winters and short summers, look for varieties bred for an early harvest. When choosing between hybrid and heirloom seeds, hybrids tend to produce more firm sprouts but some heirlooms can have unbeatable flavor.
Getting the Site Ready
Add Organic Matter
Brussels sprouts take a long time to grow, which means it’s a good idea to amend the garden bed with plenty of well-rotted manure or rich compost before planting or plant after a cover crop. A healthy dose of organic matter will decompose slowly, providing lots of good nutrition to plants as they grow throughout the season.
Do a Soil Test
An important part of site preparation is to start with a soil test. Testing your soil is a great way to learn your soil’s pH level (or the level of acidity), nutrient availability and the amount of organic matter present. This information will allow you to plan your fertilizer regimen and let you know whether you need to raise or lower the pH for your Brussels sprouts (shoot for pH between 6 and 7). Some soil test services will provide a report with advice specific to what crops you plan to grow.
Practice Crop Rotation
Members of the Brassica family – including Brussels sprouts, broccoli, cabbage and turnips – are usually susceptible to the same health problems. Pests can lay their eggs or overwinter in the soil, and disease populations may build in the garden bed. When you decide where to plant your Brussels sprouts this season, look for a spot where you haven’t grown this crop or its relatives for the past few years. Rotating where you grow these crops each season will help your brassicas start the season strong without fighting previous years’ pests from the start.
How to Plant Brussels Sprouts
When Do Brussels Sprouts Grow Best?
Brussels sprouts perform best with full sun (6 or more hours a day), rich soil and consistent watering. Although they tolerate both cold and warm weather, most of their active growth happens when temperatures are around 60 degrees. Brussels sprouts also take a long time to mature – usually around 100 days after planting seedlings out in the garden.
In most parts of the country, Brussels sprouts are often started indoors in the spring, planted outside after the danger of frost has passed, grown through the summer and harvested in the fall. Even though Brussels sprouts usually grow through the summer in many areas, they can languish in the intense heat of the Deep South. Southern gardeners may have a better crop if they wait to plant their sprouts in the fall and grow through cool winter weather. Check with your state or county extension service to learn the best time to grow Brussels sprouts in your area.
How to Start Brussels Sprouts Indoors
Plant your Brussels sprouts indoors 4 to 6 weeks before your region’s average last frost. You should begin by planting twice as many seeds as you’ll need, just in case any of the seedlings don’t perform well. Fill a shallow flower pot or planting tray with a fine seedling mix, then sow and then lightly cover your seeds. The seeds should sprout within two weeks. After the seeds germinate, give them some light from a sunny window or a bright grow-light.
Once your seedlings each have 4 or 5 leaves, it’s time to prick them out and move each plant to its own 4-inch pot. Lift each seedling carefully, place it into the center of the pot, gently firm the soil in around the roots and then give it a good drink. Pot up your seedlings into 6-inch pots instead of 4-inch pots if you are concerned about clubroot disease
Start to acclimate your seedlings to life outdoors (also called "hardening off") a couple of weeks before you plan to plant them in the garden. Move the pots into a sunny, sheltered spot outside during the day and bring them inside at night. If the forecast calls for temperatures below 45 degrees, keep your seedlings indoors until the weather warms up.
Planting Brussels Sprouts in the Garden
It’s time to plant out Brussels sprouts when the plants have filled their pots with roots. How far apart should Brussels sprouts be planted? Check the seed packet or plant label for the spacing requirements of the variety you’re growing, but a good rule of thumb is to space plants about 2 feet apart. Gently firm in the soil around each plant — a plant shouldn’t lift out of the ground if you lightly tug on its leaves.
Growing and Caring for Brussels Sprout Plants
Give your Brussels sprouts a good drink every few days early in the season. Rainwater may be sufficient for your plants once they’re established in midsummer. You will need to water your Brussels sprouts if your garden doesn’t receive at least 1 inch of water a week from rain.
Brussels sprout plants can grow up to 3 feet tall. As the young sprouts develop along the stem, their added weight can cause plants to flop over or even break. Tie your Brussels sprouts stems to a stake to keep plants secure.
"Top Plants" to Harvest Whole Stalk
When the lowest sprouts on the stem are a 1/2 inch wide, it’s time to "top" your plants. Use your fingers to pinch the new growth at the very top of the stem. This will send a signal to your plant that it’s time to focus its energy on developing those heads. Plants that have been topped should produce sprouts that are all ready to harvest at roughly the same time instead of producing sprouts that mature from the base of the stem up to the top. Topping your plants will also help produce firm heads rather than open, leafy sprouts.
Weed the garden on a regular basis to prevent competition for water, sunlight and nutrients. Pull up weeds while they’re young if at all possible to avoid disturbing your Brussels sprouts’ surface roots. A healthy layer of straw, pine straw, wood chips or compost mulch will suppress weeds while feeding the soil and conserving water.
Scout for Health Issues
Unfortunately, brassicas are susceptible to a host of pests and diseases and Brussels sprouts are no exception. When it comes to protecting your Brussels sprouts, the best defense is a good offense. Following good practices such as crop rotation (see section above), starting with disease-free seed and companion planting are helpful ways to limit health issues. Keeping an eye out for problems will allow you to quickly find a solution before any serious damage happens.
Regularly scout for insect pests like flea beetles, cabbage aphids, cabbage whiteflies and cabbage loopers. Start out the season with a floating row cover to protect veggies as they grow – especially if you’ve struggled with any of these problems on Brussels sprouts or its relatives in the past.
Cabbage maggot flies can seriously damage Brussels sprout seedlings. Adult flies will lay their eggs at the base of a plant. When the eggs hatch, maggots work their way into the soil to feed on the plant roots, stunting the plants. Give each seedling its own root collar after planting to discourage cabbage maggot fly damage. This small, circular piece of cardboard with a hole in the center for the plant will stop cabbage maggot flies from laying their eggs near your Brussels sprouts.
Treat your plants with Bt (Bacillus thuringiensis) if cabbage loopers or other caterpillars begin to be a serious problem on your crop. Bt is a naturally occurring microbe that, when eaten by caterpillars, activates toxins in the digestive system that will eventually stop them from eating your veggies.
How to Harvest Brussels Sprouts
Hold off on harvesting your Brussels sprouts until after the first frost if at all possible. Believe it or not, chilly weather can make Brussels sprouts taste sweeter. Cold weather only improves the harvest and plants aren’t damaged until temperatures dip below 20 degrees.
Brussels sprouts are ready to harvest when the heads are about the size of a quarter. Simply twist the head to remove it from the stalk. If you didn’t top your plants earlier in the season (see section above), the sprouts at the bottom of the stem will be ready to harvest first. Begin harvesting at the base of the plant and come back later as the other heads mature. Remove the lower leaves to speed up head development.
If you did top your plants, all of your Brussels sprouts should be ready to harvest at the same time. You can twist off individual heads or harvest the entire stalk by cutting the base of the plant.
Brussels sprouts leaves are delicious, too. After you’ve harvested the heads, pick the leaves and use them as you would collard greens.