Cabbage in Zone 5B — Midwest

Cabbage is a rewarding crop for Midwest gardeners. Its crisp texture and mild flavor make it perfect for slaws, stir-fries, and even roasting. Plus, there's a certain satisfaction in harvesting a dense, beautiful head of cabbage after nurturing it through our variable Midwest weather.

Our springs can be unpredictable, and we sometimes get summer heat spells. But with a little planning and attention to timing within our 168-day growing season, you can definitely grow fantastic cabbage right here in Zone 5B.

For a spring harvest, start your cabbage seeds indoors from late February through mid March. This gives them about 6 weeks to get a head start before transplanting. You'll want to use seed trays or small pots filled with a good seed-starting mix.

Keep the trays in a warm spot (around 70°F) and provide plenty of light, either from a sunny window or a grow light. Bottom watering is a great way to keep the soil consistently moist without overwatering – just set the tray in a shallow dish of water and let the soil soak it up. Given our moderate-to-late spring, this indoor start is crucial for getting a good harvest.

Transplant your cabbage seedlings outdoors from mid April through early May, after hardening them off for about a week. Hardening off simply means gradually exposing the seedlings to outdoor conditions. Start with an hour or two of sunlight and increase the time each day.

Space the plants 12-18 inches apart in rows. Keep an eye on the weather forecast around transplant time; we sometimes get a late frost in the Midwest, so be prepared to cover your seedlings if necessary.

Cabbage needs consistent moisture to thrive, but overwatering can be just as bad as underwatering. In the Midwest, our wet-summer rainfall helps, but you'll still need to monitor the soil moisture, especially during summer heat spells. Stick your finger about 2 inches deep into the soil – if it feels dry, it's time to water.

Aim for about 1-1.5 inches of water per week, depending on rainfall. Water at the base of the plant rather than overhead to minimize the risk of fungal diseases, which can be a problem with our moderate-to-humid humidity. If the leaves start to wilt or turn yellow, you might be underwatering. If the leaves are yellowing and the plant seems waterlogged, you're likely overwatering.

A layer of mulch around your cabbage plants will help retain moisture and suppress weeds, which is always a win. Straw, shredded leaves, or even grass clippings work well.

Your cabbage should be ready to harvest from mid June through early August, about 70 days after transplanting. The best way to tell if a head of cabbage is ripe is to give it a gentle squeeze. It should feel firm and solid. It should also be a good size for the variety you’re growing.

To harvest, simply cut the head off at the base with a sharp knife. If you still have some smaller cabbages growing as our first frost approaches in early October, harvest them even if they aren't quite fully mature. They'll still be delicious in slaws and soups.

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

Cabbage Worms *What it looks like:* You'll see smooth green caterpillars munching on your cabbage leaves, leaving irregular holes and dark green droppings behind. You might also notice white butterflies fluttering around. *What causes it:* These are the larvae of those white cabbage butterflies. They can go through multiple generations during our warm summers. *How to fix/prevent it:* Bt spray is very effective for controlling cabbage worms. Floating row covers can prevent the butterflies from laying eggs in the first place. You can also handpick the caterpillars or interplant with aromatic herbs like thyme and sage to deter the butterflies.

Cabbage Loopers *What it looks like:* Similar to cabbage worms, but these caterpillars move with a looping motion. They also chew holes in leaves. *What causes it:* Cabbage loopers are another type of caterpillar that thrives in warm weather. *How to fix/prevent it:* Bt spray works well on cabbage loopers, too. You can also use row covers or handpick them.

Splitting *What it looks like:* The cabbage head cracks open. *What causes it:* Inconsistent watering, especially heavy watering after a dry spell. The head grows too quickly and the outer leaves can't keep up. *How to fix/prevent it:* Consistent watering is key. Try to maintain even soil moisture. Mulching can help. If heavy rain is expected, you can try twisting the head slightly to break some of the roots and slow down growth.

Clubroot *What it looks like:* Stunted growth, wilting leaves (especially in the afternoon heat), and yellowing leaves. If you dig up the plant, the roots will be swollen and distorted. *What causes it:* A soil-borne pathogen that can persist in the soil for many years. It favors acidic, wet soil. *How to fix/prevent it:* Raise the soil pH to 7.0-7.2 with lime. Improve drainage. Rotate your brassica crops on a 7-year cycle. Remove and destroy infected plants (don't compost them). Start your transplants in a sterile mix.

*Midwest Specific Challenges:* Our moderate-to-hot summer heat and moderate-to-humid humidity can create ideal conditions for pests like cabbage worms and loopers. Also, our wet-summer rainfall can make it challenging to maintain consistent soil moisture and prevent splitting.

Good companions for cabbage include green beans, celery, onions, potatoes, and dill. Green beans fix nitrogen in the soil, which benefits cabbage. Celery is said to deter cabbage white butterflies. Onions and dill have strong scents that can confuse pests. Potatoes don't compete for the same nutrients and can provide some shade.

Avoid planting cabbage near tomatoes, strawberries, and peppers. Tomatoes and peppers are susceptible to some of the same diseases as cabbage. Strawberries can attract slugs, which may also feed on cabbage.