Cabbage is a cornerstone of the home garden. It is a hardy, versatile vegetable that rewards the patient gardener with dense, nutritious heads. Growing cabbage from seed gives you access to a much wider variety of cultivars than you will find at a local nursery. From the crinkled leaves of Savoy to the vibrant hues of Red Acre, starting from seed is the best way to customize your harvest.
Understanding Cabbage Varieties
Before you press a single seed into the soil, you must choose the right variety for your climate and kitchen. Cabbage varieties are generally categorized by their maturity dates and physical characteristics.
- Early Varieties: These reach maturity in 50 to 60 days. They are ideal for gardeners with short spring seasons.
- Mid-Season Varieties: These take roughly 75 to 85 days. They often produce larger heads than early types.
- Late Varieties: These require 100 days or more. They are usually the best candidates for winter storage or sauerkraut.
Timing Your Planting
Cabbage is a cool-season crop. It thrives in temperatures between 45°F and 75°F. If the weather becomes too hot, the plant may “bolt,” which means it sends up a flower stalk and becomes bitter.
For a spring crop, start your seeds indoors 6 to 8 weeks before the last expected frost. For a fall crop, start seeds in mid-to-late summer, roughly 10 to 12 weeks before the first expected fall frost. Cabbage can tolerate a light frost, and many gardeners believe a touch of cold actually improves the flavor.
Preparing the Seed Starting Mix
Cabbage seeds need a light, well-draining medium to germinate successfully. Do not use standard garden soil for starting seeds indoors. Garden soil is too heavy and may contain pathogens that cause “damping off,” a fungal disease that kills young seedlings.
Use a high-quality seed starting mix. This is usually a soilless blend of peat moss or coconut coir, perlite, and vermiculite. Moisten the mix before putting it into your seed trays. It should feel like a wrung-out sponge—damp but not dripping wet.
Sowing the Seeds
Fill your seed trays or soil blocks with the moistened mix. Press down lightly to remove large air pockets. Place two seeds in each cell. Cabbage seeds are small, so they only need to be planted about 1/4 inch deep.
Cover the seeds lightly with more mix and mist the surface with water. Place the trays in a warm spot. Cabbage seeds germinate best when the soil temperature is between 65°F and 75°F. You can use a waterproof seedling heat mat to maintain a consistent temperature.
Caring for Seedlings Indoors
Once the green loops of the seedlings emerge, they need light immediately. Move them to a very bright south-facing window or, preferably, under LED or fluorescent grow lights. Keep the lights about 2 to 3 inches above the tops of the plants to prevent them from becoming “leggy” or stretched out.
If both seeds in a cell germinate, use a small pair of scissors to snip the smaller one at the soil line. This ensures the strongest plant has plenty of room for its roots. Keep the soil consistently moist but never waterlogged.
Hardening Off the Plants
You cannot move pampered indoor seedlings directly into the garden. They need to be “hardened off.” This is a gradual process of acclimating them to outdoor conditions like wind, direct sun, and temperature fluctuations.
Start by placing your seedlings in a shaded, sheltered spot outside for one hour. Each day, increase the time they spend outside and their exposure to direct sunlight. After 7 to 10 days of this process, your plants will be tough enough to survive the garden environment.
Selecting the Right Garden Spot
Cabbage requires full sun, which means at least 6 to 8 hours of direct sunlight per day. It also needs soil that is rich in organic matter. Cabbage is a “heavy feeder,” meaning it pulls a significant amount of nutrients from the earth.
Before planting, work several inches of compost or well-rotted manure into the soil. The ideal soil pH for cabbage is between 6.5 and 6.8. This slightly acidic to neutral range helps prevent clubroot, a common cabbage disease.
Transplanting into the Garden
Space your cabbage plants 12 to 18 inches apart in rows that are 24 inches apart. If you space them closer, you will get smaller heads. If you space them further apart, the heads will grow much larger.
Dig a hole deep enough to cover the root ball and the stem up to the first set of true leaves. This provides extra stability for the plant. Firm the soil gently around the base and water deeply immediately after transplanting to settle the roots.
Ongoing Maintenance and Care
Success with cabbage depends on two main factors: consistent moisture and nitrogen.
Cabbage has a shallow root system. It needs frequent, shallow watering rather than occasional deep soaking. If the soil dries out completely and then becomes very wet, the heads may split open. Aim for about one inch of water per week.
Mulching around the plants with straw or shredded leaves is highly recommended. Mulch helps retain soil moisture, suppresses weeds, and keeps the soil temperature cool.
Since cabbage is a leafy green, it needs plenty of nitrogen. Apply a balanced organic fertilizer or a side-dressing of compost every 3 to 4 weeks during the growing season. Stop fertilizing once the heads begin to feel firm.
Managing Pests and Diseases
Cabbage attracts several common pests. The most notorious is the imported cabbageworm, which is the larvae of the white butterfly often seen fluttering around the garden. These green caterpillars can quickly eat holes through the leaves.
Using lightweight floating row covers is the most effective way to prevent pests. These covers act as a physical barrier so the butterflies cannot lay eggs on your plants. If you already have worms, you can pick them off by hand or use an organic spray containing Bacillus thuringiensis (Bt).
Watch out for aphids and slugs as well. A strong spray of water can dislodge aphids, while beer traps or diatomaceous earth can help control slugs.
Harvesting Your Cabbage
Cabbage is ready to harvest when the head feels firm and solid when squeezed. If the head feels soft or “squishy,” it needs more time to fill out.
To harvest, use a sharp knife to cut the head at the base, just above the outer wrapper leaves. Leave the wide, loose outer leaves in the garden to compost. If you leave the roots and the bottom of the stem in the ground for early varieties, you may sometimes get a second harvest of several small “cabbage sprouts” from the remaining stalk.
Frequently Asked Questions
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Why are my cabbage seeds not germinating?
The most common reasons for poor germination are old seeds, soil that is too cold, or soil that is too dry. Cabbage seeds generally remain viable for 3 to 4 years if stored in a cool, dark place. Ensure your soil temperature is at least 60°F for the best results.
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Can I grow cabbage in containers?
Yes, cabbage can be grown in containers. Use a pot that holds at least 5 gallons of soil per plant. Ensure the container has excellent drainage and monitor the moisture levels closely, as pots dry out much faster than garden beds.
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What causes cabbage heads to split?
Splitting is usually caused by an uneven supply of water. If a plant experiences a dry spell followed by heavy rain or heavy watering, the inner leaves grow faster than the outer leaves can expand, causing the head to burst. Keeping the soil consistently moist with mulch can prevent this.
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How do I know if my cabbage has clubroot?
Clubroot is a soil-borne fungus that causes the roots to become swollen, distorted, and “club-like.” Above ground, the plant will wilt during the heat of the day and may appear stunted or yellowed. Rotating crops and maintaining a soil pH above 6.8 can help prevent this disease.
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Is cabbage frost tolerant?
Yes, cabbage is quite frost-tolerant. Mature plants can survive temperatures as low as 20°F for short periods. Many gardeners prefer to harvest cabbage after a light frost, as the cold triggers the plant to convert starches into sugars, resulting in a sweeter flavor.