Brussels Sprouts in Zone 6A — Midwest

Brussels sprouts might not be the first thing that comes to mind when you think of Midwest gardens, but they're surprisingly rewarding. Freshly harvested, homegrown sprouts have a sweetness and nutty flavor that store-bought ones just can't match. Plus, they're incredibly versatile in the kitchen, and there's nothing quite like the satisfaction of harvesting those little green gems after a long growing season.

Sure, our Midwest weather can throw curveballs, from late frosts to summer heat spells, but with a little planning, you can absolutely grow fantastic Brussels sprouts. Our fertile soil and adequate rainfall give them a great head start, and the 178-day growing season gives you plenty of time to get them to harvest, especially if you start them indoors.

Starting your Brussels sprouts indoors is the way to go here in the Midwest. Aim to sow your seeds early to late March, about 6 weeks before you plan to transplant them outside. This gives them a head start on our sometimes-moderate-to-late spring.

You'll need seed trays or small pots filled with a good seed-starting mix. Keep them warm and provide plenty of light – a grow light works wonders. Water gently from the bottom to avoid damping off. This ensures the seedlings get moisture without overly wetting the foliage.

Transplanting Brussels sprouts is best done mid April through mid May. Before you move them outside, harden them off for about a week. Gradually expose them to outdoor conditions, starting with just a few hours a day.

When you transplant, space the seedlings 18-24 inches apart. Keep an eye on the weather forecast; those unexpected late frosts can still sneak in and damage young plants.

Brussels sprouts need consistent moisture to develop those tight, flavorful sprouts we're after. A lack of water, especially during summer heat spells, can lead to loose, bitter sprouts – not what you want. Aim for about 1-1.5 inches of water per week, including rainfall.

Stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Water at the base of the plants to avoid getting the foliage wet, which can encourage fungal diseases in our moderate-to-humid climate.

Pay attention to your plants. If the leaves are wilting or turning yellow, they're likely underwatered. Overwatering can cause root rot, so make sure your soil drains well. A layer of mulch, like straw or shredded leaves, can help retain moisture and keep the soil cool during the summer.

Brussels sprouts can get tall and top-heavy, especially when loaded with sprouts. That's why staking them is a good idea, particularly with our occasional strong winds.

A sturdy stake works best. Insert it near the plant at transplanting time to avoid damaging the roots later. As the plant grows, gently tie the stalk to the stake with soft twine. This will help prevent the plant from toppling over and keep those sprouts off the ground.

Pruning Brussels sprouts is pretty straightforward. As the sprouts start to develop from the bottom up, remove the yellowing or damaged lower leaves. This helps improve air circulation and allows the plant to focus its energy on the developing sprouts.

About 3-4 weeks before you plan to harvest, top the plant by cutting off the top cluster of leaves. This encourages the plant to put all its energy into maturing the sprouts. As our first frost approaches around mid- October, this can help speed things along.

You can expect your first harvest of Brussels sprouts mid July through late August, about 90 days after planting. The sprouts are ready when they're firm, tight, and about 1-2 inches in diameter. Harvest from the bottom up by twisting or cutting the sprouts off the stalk.

Don't be afraid to let the plants experience a frost or two before harvesting. The cold actually improves the flavor, making the sprouts sweeter. Brussels sprouts will continue to produce as long as the weather allows.

As the first frost approaches in mid- October, you can harvest the entire stalk and store it in a cool, dark place. The sprouts will continue to mature, giving you a supply of fresh Brussels sprouts well into the fall.

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

Aphids *What it looks like:* Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth. *What causes it:* These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies often farm them. *How to fix/prevent it:* A strong spray of water can knock them off. Encourage ladybugs and lacewings. Use insecticidal soap or neem oil for heavy infestations. Avoid excess nitrogen fertilizer.

Cabbage Worms *What it looks like:* Smooth green caterpillars chewing irregular holes in the leaves. Dark green droppings. White butterflies fluttering around your plants. *What causes it:* These are the larvae of white cabbage butterflies, and they can go through multiple generations in our warm summers. *How to fix/prevent it:* Bt spray is very effective. Floating row covers can prevent the butterflies from laying eggs. Handpick the caterpillars when you see them. Interplant with aromatic herbs like thyme and sage.

Loose Sprouts from Heat *What it looks like:* Sprouts that don't form tight heads, remaining leafy and loose. Often bitter in taste. *What causes it:* Extended periods of high temperatures during sprout formation. The plant struggles to form dense sprouts in the heat. *How to fix/prevent it:* Provide consistent watering, especially during hot spells. Mulch around the plants to keep the soil cool. Consider planting varieties that are more heat-tolerant.

Clubroot *What it looks like:* Stunted growth, wilting in the afternoon heat, and yellowing leaves. When you dig up the plant, the roots are swollen, distorted, and club-shaped. *What causes it:* A soil-borne pathogen that can persist in the soil for years. It thrives in acidic, wet soil. *How to fix/prevent it:* Raise the soil pH to 7.0-7.2 with lime. Improve drainage. Rotate brassicas on a 7-year cycle. Remove and destroy infected plants. Start transplants in a sterile mix.

Midwest Specific Challenges: The moderate-to-hot heat and moderate-to-humid humidity of our Midwest summers can stress Brussels sprouts, making them more susceptible to pests and diseases. Wet-summer rainfall can also contribute to soil-borne diseases like clubroot. Consistent monitoring and proactive measures are key to success.

Companion planting can give your Brussels sprouts a boost. Green beans, celery, onions, potatoes, and dill are all good companions. Green beans fix nitrogen in the soil, benefiting the Brussels sprouts. Celery and onions repel some pests, while dill attracts beneficial insects. Potatoes don't compete for the same nutrients.

Avoid planting tomatoes, strawberries, or peppers near your Brussels sprouts. Tomatoes and peppers can attract similar pests, and strawberries can compete for nutrients. It's all about creating a beneficial environment in your garden!