Cabbage in Zone 5A — Midwest

Cabbage is a rewarding crop to grow here in the Midwest. The heads are delicious raw, cooked, or fermented into sauerkraut, and you can get a lot of use out of just a few plants. Plus, Cabbage thrives in our fertile soil and appreciates the summer heat spells we often get, making it a great addition to your garden.

While we do have our share of Midwest weather challenges, like variable springs and the occasional summer heat spells, Cabbage is surprisingly resilient. With a 157-day growing season, we have a good window to get Cabbage from seed to harvest, especially if you start indoors.

To get a head start on your Cabbage crop, start your seeds indoors from late February through mid March. This gives you about 6 weeks to nurture the seedlings before the weather warms up enough for transplanting, which is crucial given our moderate-to-late spring. Use seed trays or small pots filled with a good seed-starting mix.

Keep the soil consistently moist, but not soggy. A good trick is to water from the bottom by placing the tray in a shallow dish of water, allowing the soil to soak it up. Place the trays in a warm location and provide plenty of light, either from a sunny window or a grow light.

Transplant your Cabbage seedlings outdoors from mid April through mid May. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind, which can be intense even in the early spring here in the Midwest.

Space the plants 12-18 inches apart in rows. Our springs can be so variable so keep an eye on the forecast and cover the seedlings if a late frost is predicted.

Cabbage needs consistent moisture to form tight, healthy heads. Our wet summers usually provide a good base, but it’s still important to monitor the soil moisture regularly. Stick your finger about 2 inches deep into the soil – if it feels dry, it’s time to water.

Aim for about 1 inch of water per week, especially during dry spells. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our moderate-to-humid conditions. Overhead watering is fine, just do it in the morning to give the leaves time to dry out.

Pay attention to your plants. Wilting leaves indicate underwatering, while yellowing leaves could mean overwatering. Mulching around your Cabbage plants helps retain moisture and suppress weeds. Use straw or shredded leaves, which are readily available here in the Midwest.

You can expect your first Cabbage harvest from late June through mid August, about 70 days after transplanting. The key is to check for firmness. When the head feels solid and dense when squeezed, and has reached its full size for the variety, it's ready to harvest.

Use a sharp knife to cut the head at its base. Leave a few outer leaves on the stem; these can sometimes produce smaller side heads later on.

As our first frost approaches in early October, harvest any remaining mature heads. Even a light frost can damage them. Smaller, less mature heads can sometimes be salvaged by covering them with a blanket or row cover if a light frost is predicted, but it's best to harvest them if they're close to maturity.

Here are some common problems you might encounter growing Cabbage in the Midwest:

Cabbage Worms

• What it looks like: Smooth green caterpillars on brassica leaves. Irregular holes chewed in leaves. Dark green droppings. White butterflies hovering around plants.
• What causes it: Larvae of white cabbage butterflies. Multiple generations per season in our warm summers.
• How to fix/prevent it: Bt spray is very effective. Floating row covers prevent egg laying. Handpick caterpillars. Interplant with aromatic herbs (thyme, sage). Encourage parasitic wasps.

Cabbage Loopers

• What it looks like: Similar to cabbage worms, but loopers move with a distinctive looping motion. They also chew holes in leaves.
• What causes it: Another type of caterpillar attracted to brassicas.
• How to fix/prevent it: Same methods as cabbage worms: Bt spray, row covers, handpicking.

Splitting

• What it looks like: The Cabbage head cracks open.
• What causes it: Inconsistent watering. Heavy watering after a dry spell causes the head to grow too quickly and split. The wet-summer rainfall we get here in the Midwest can also contribute.
• How to fix/prevent it: Water regularly and consistently. Mulch to retain moisture. Harvest mature heads promptly to prevent splitting.

Clubroot

• What it looks like: Stunted growth, wilting in afternoon heat, yellowing leaves. Roots are swollen, distorted, and club-shaped when dug up.
• What causes it: Soil-borne pathogen (Plasmodiophora brassicae) that persists in soil for 10+ years. Favors acidic, wet soil.
• How to fix/prevent it: Raise soil pH to 7.0-7.2 with lime. Improve drainage. Rotate brassicas on a 7-year cycle. Remove and destroy infected plants (don't compost). Start transplants in sterile mix.

Midwest Specific Challenges: Our moderate-to-hot summer heat and moderate-to-humid humidity can create ideal conditions for pests and diseases. Regular monitoring and prompt action are key to keeping your Cabbage healthy. The wet-summer rainfall can make consistent watering tricky, so pay close attention to the forecast and adjust your watering schedule accordingly.

Companion planting can really help your Cabbage thrive. Green beans are great because they fix nitrogen in the soil, which Cabbage loves. Celery can help deter cabbage white butterflies, reducing the risk of cabbage worms. Onions also deter pests, and potatoes won't compete for the same nutrients. Dill attracts beneficial insects like ladybugs and hoverflies, which prey on aphids and other pests.

Avoid planting Cabbage near tomatoes, strawberries, or peppers. Tomatoes and strawberries are susceptible to some of the same diseases as Cabbage, increasing the risk of infection. Peppers can stunt the growth of Cabbage.