Brussels Sprouts in Zone 6A — Southeast

Brussels sprouts might not be the first thing that comes to mind for a Southern garden, but don't let that fool you. When roasted, grilled, or even shredded in a slaw, their nutty flavor really shines, and they're surprisingly versatile in the kitchen. Plus, there's something deeply satisfying about harvesting those little cabbages you grew yourself.

Our hot and humid summers here in Zone 6A can present some challenges, but with careful timing, you can absolutely grow a great crop of Brussels sprouts. Our long 198-day growing season gives you options for both a summer and fall harvest, so don't be intimidated.

Starting your Brussels sprouts indoors gives you a head start against the heat and pests. Aim to sow your seeds from mid February through mid March, about six weeks before you plan to set them out in the garden. This moderate spring weather helps the seedlings get established.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist – bottom watering works great to prevent damping off. Provide warmth and plenty of light, either with a sunny windowsill or grow lights.

Remember, Brussels sprouts need a long growing season (around 90 days), so getting them going indoors early is key for a successful harvest, especially if you're aiming for a summer crop.

Transplant your Brussels sprouts seedlings outdoors from early April through early May, once the danger of a hard frost has passed. Before you move them permanently, be sure to harden them off by gradually exposing them to outdoor conditions for about a week. This toughens them up and prevents transplant shock.

Space your plants 18-24 inches apart to allow for good air circulation. This is particularly important in our humid climate to help prevent fungal diseases. Keep an eye out for late frosts, as they can still occur this time of year.

Consistent moisture is crucial for growing plump, delicious Brussels sprouts. Inconsistent watering can lead to loose, bitter sprouts, and nobody wants that. Especially during our hot summers, those plants need attention.

During the hottest part of the summer, you’ll likely need to water deeply a couple of times a week, providing about 1-1.5 inches of water each time. Stick your finger about two inches deep into the soil – if it feels dry, it’s time to water. With our humid summers, it's best to water at the base of the plants to avoid getting the leaves too wet, which can encourage fungal diseases.

Keep an eye out for wilting leaves, which indicates underwatering, or yellowing leaves, which can be a sign of overwatering. A good layer of mulch, like straw or shredded leaves, will help retain moisture in the soil and keep the roots cool.

Brussels sprouts plants can get quite tall and top-heavy, especially when those sprouts start to develop. Our afternoon thunderstorms can also bring strong winds, which can easily topple unsupported plants. Staking your Brussels sprouts is a good idea to keep them upright and healthy.

A sturdy stake, like a bamboo or wooden stake, works best. Insert the stake near the plant when it reaches about 2 feet tall, being careful not to damage the roots. Use soft twine or plant ties to loosely attach the stalk to the stake.

Brussels sprouts don't require a lot of pruning, but a little maintenance can help improve your harvest. As the sprouts develop up the stalk, remove the yellowing or damaged lower leaves. This improves air circulation and directs the plant's energy towards sprout production.

About 3-4 weeks before your expected harvest, top the plant by cutting off the top set of leaves. This encourages the plant to put all its energy into the existing sprouts.

As our first frost approaches in late October, you can remove any remaining leaves to allow the sprouts to mature fully before the cold weather hits.

You can expect your first harvest of Brussels sprouts from early July through mid August, about 90 days after transplanting. The sprouts are ready to pick when they are firm, tight, and about 1-2 inches in diameter. Harvest from the bottom of the stalk upwards, twisting or cutting off the sprouts.

After you pick the lower sprouts, the plant will continue to produce more further up the stalk, giving you a continuous harvest over several weeks. And here's a tip: Brussels sprouts actually taste even better after a light frost, so don't be afraid to leave them in the garden as long as possible.

As late October rolls around and the first frost threatens, harvest any remaining sprouts. They'll keep well in the refrigerator for a week or two.

Here are some common problems you might encounter with Brussels sprouts in the Southeast:

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. You'll also see sticky honeydew and curled or distorted new growth.
• What causes it: These sap-sucking insects thrive in warm weather and can reproduce rapidly. Ants often protect them.
• How to fix/prevent it: A strong spray of water can knock them off. Encourage beneficial insects like ladybugs. Use insecticidal soap or neem oil for heavy infestations. Avoid over-fertilizing with nitrogen.

Cabbage Worms

• What it looks like: Smooth green caterpillars chewing holes in leaves. You'll also see dark green droppings and white cabbage butterflies fluttering around.
• What causes it: These are the larvae of those white cabbage butterflies, and they can go through multiple generations in our long, warm season.
• How to fix/prevent it: Bt spray is very effective. Use floating row covers to prevent the butterflies from laying eggs. Handpick caterpillars when you see them.

Loose Sprouts from Heat

• What it looks like: Sprouts that are not tightly formed and feel loose to the touch. They may also taste bitter.
• What causes it: High temperatures during sprout development can cause them to loosen up.
• How to fix/prevent it: Consistent watering is key. Provide afternoon shade if possible. Choose heat-tolerant varieties. Aim for a fall harvest when temperatures are cooler.

Clubroot

• What it looks like: Stunted growth, wilting in the afternoon, yellowing leaves. Roots are swollen and distorted.
• What causes it: A soil-borne pathogen that can persist for years, especially in acidic, wet soil.
• How to fix/prevent it: Raise soil pH with lime. Improve drainage. Rotate brassicas on a 7-year cycle. Remove and destroy infected plants.

Southeast Specific Challenges: Our hot and humid summers create the perfect conditions for fungal diseases, so good air circulation and proper watering are essential. Japanese beetles can also be a nuisance, so keep an eye out for them. Deer love Brussels sprouts, so you may need to use fencing or other deterrents to protect your plants.

Companion planting can give your Brussels sprouts a boost. Green beans fix nitrogen in the soil, benefiting the Brussels sprouts. Celery helps deter cabbage white butterflies, while onions repel aphids. Potatoes don't directly help the Brussels sprouts, but they're heavy feeders, so they won't compete for nutrients. Dill attracts beneficial insects that prey on pests.

Avoid planting Brussels sprouts near tomatoes, strawberries, or peppers. Tomatoes and peppers are susceptible to similar pests and diseases, increasing the risk of problems. Strawberries can stunt the growth of brassicas like Brussels sprouts.