How to Plant, Grow, and Care for ‘January King’ Cabbage

‘January King’ is an exceptional cabbage with impressive cold-hardiness and beautiful color. In this article, vegetable farmer Briana Yablonski will share tips and tricks for caring for these plants.

A dense head of purple and green leaves with ruffled edges.

Contents

Although many hybrid cabbage varieties exist, growers still love the heirloom January King. This variety has impressive cold tolerance, beautiful color, and great flavor.

If you want to grow this cabbage in your garden, you should be aware of its long maturity time and common pests and diseases. I’ll explain how to start them from seed, provide the proper growing environment, and keep your ‘January King’ cabbages happy until they’re ready to harvest.

Raised Garden Beds

Short Birdies Small Modular Raised Garden Bed

Our raised garden beds come in many different shapes and sizes. We offer raised beds in a variety of different materials, including high-performance aluzinc steel and cedar wood.

View at Epic Gardening

Brassica oleracea ‘January King’ Cabbage Overview

Detailed view of overlapping purple leaves with green veins. .
Plant Type Vegetative annual
Family Brassica
Genus Brassicaceae
Species Oleracea var. sabauda
Native Area Europe
Exposure Full sun
Height 6-12 inches
Watering Requirements Moderate
Pests & Diseases Flea beetles, cabbage worms, harlequin bugs, black rot, alternaria leaf spot
Maintenance Low
Soil Type Rich and well-draining
Hardiness Zone 3-9

What Is It?

A compact head of ruffled leaves in shades of purple and green, with darker outer leaves and lighter green streaks near the center.
The purple-tinged heads remain crisp and delicious even when temperatures dip to 5°F.

While some cultivar names leave us guessing, the meaning behind ‘January King’ is straightforward. This impressively cold-hardy cabbage stands out in barren winter fields when other veggies and ornamentals have succumbed to the cold. The purple-tinged heads remain crisp and delicious even when temperatures dip to 5°F (-15°C).

Gardeners have been growing this heirloom variety for over 100 years. Although seed breeders introduced many hybrid cabbages during this time, ‘January King’ remains a favorite among many growers.

Characteristics

Frozen curly-leaved ornamental cabbage displays its frilled, green and purple leaves, glistening with frost, surrounded by heather plants blanketed in a layer of soft snow.
They have wrinkled leaves similar to those of most savoy varieties, but the outer leaves resemble those of white cabbage.

‘January King’ is a slow-growing cabbage described as a cross between a white and savoy cabbage. The plants have wrinkled leaves similar to those of most savoy varieties, but the outer leaves resemble those of white cabbage. When the slightly flat heads are mature, they weigh between three and five pounds and have purple-tinged outer leaves.

Although this cabbage is cold-tolerant, it matures slowly. Depending on when and where you plant it, expect it to take 160-210 days to mature.

Native Area

A mix of green and purple Brassica heads placed together, showing their compact leaves and varying textures.
Plant breeders have taken this native plant and bred it to produce modern varieties of cabbage, cauliflower, and kale.

Although the versions of Brassica oleracea we grow in our gardens vary drastically from the wild version, scientists think the original plant is native to Europe. Plant breeders have taken this native plant and bred it to produce modern varieties of cabbage, cauliflower, and kale.

Planting

Rows of leafy Brassica plants with broad green leaves and visible veins, growing in a cultivated field.
Like most cabbages, it’s a cool-weather crop that grows best in spring, fall, and winter.

‘January King’ cabbage grows best outdoors in the ground or in raised beds. Like most cabbages, it’s a cool-weather crop that grows best in spring, fall, and winter. Fall crops are easier to grow (and allow you to utilize the plant’s cold hardiness), but you can also try to produce spring cabbages.

Growing from Seed

Small Brassica seedlings growing in brown soil within rectangular trays.
Fill each tray with moist soil mix, make a quarter-inch hole in each cell, place one to two seeds, and gently cover.

Unless you can find ‘January King’ seedlings at a nearby nursery or garden center, plan on growing these brassicas from seed. Fortunately, this is an easy process.

Since this cabbage variety matures in about six months, you should sow the seeds well before you hope to harvest the mature heads. The ideal sowing time depends on your growing zone, but you should plan on starting seeds in January or February and again in June or July. The seedlings will be mature and ready to transplant about a month after you plant the seeds.

Cabbage grows best when transplanted, so plant to sow your seeds indoors. Start with your preferred seed starting trays and a well-draining soil mix designed for seedlings. Fill each tray with moist soil mix, make a quarter-inch hole in each cell, place one to two seeds, and gently cover.

Place the trays somewhere between 75-90°F (24-32°C) and keep the soil moist. If you don’t have a warm area, place the trays on a heat mat to warm the soil. You should see the seedlings emerge within a week.

Once germination occurs, place the seedlings in a cooler environment where the air temperature is between 55-75°F (13-24°C). You should also make sure the little seedlings receive at least ten hours of bright light each day. If you don’t have access to a south-facing window or greenhouse, you can use a grow light to provide supplemental light.

If you planted more than one seed per cell, thin to one plant per cell once the seedlings have a set of true leaves. They should be large enough to be transplanted outdoors in four to six weeks.

Transplanting

A close-up of a watering can pouring water onto a small Brassica plant in dark, moist soil.
Keep the soil moist for the first few weeks after transplanting.

Since ‘January King’ cabbages take around six months to mature, you want to make sure you get them in the ground early. That means transplanting in the late winter for spring crops and in the middle of summer for fall crops.

No matter when you transplant, remember to slowly acclimate your seedlings to outdoor light, temperature, and wind before planting them outdoors. Keep the soil moist for the first few weeks after transplanting.

If you’re planting multiple cabbages, space them 18-24” apart. You can plant fast-maturing crops like radishes, spinach, or lettuce between the plants as they grow. This interplanting will help you maximize your garden space while limiting weeds and conserving moisture.

Spring Crops

Rows of young Brassica plants with bright green leaves growing in rich brown soil, under a protective greenhouse covering.
Add an extra layer of row cover to protect them from cold damage.

The seedlings can tolerate a light frost, especially if you cover them with row cover. Therefore, you can plant them outdoors as early as the beginning of February in zones 7-9. If you expect temperatures to dip below 20°F (-7°C), add an extra layer of row cover to protect them from cold damage.

If you live in zone five or below, skipping a spring crop is best. Cold temperatures mean you won’t be able to transplant them outdoors until April or May, and this late planting date means the crops will have to mature in the warmer days of summer. Instead, plant in the summer for a fall harvest.

Fall Crops

A person using a green watering can to hydrate mature Brassica plants with broad, overlapping green leaves in a garden bed.
Keep the soil moist and watch for pests.

Harvesting these cabbages in the late fall or winter allows their cold hardiness to shine. Plus, the cooler weather causes the plants to concentrate their sugars and become delectably sweet.

Aim to transplant your plants about five to six months before you hope to harvest. For example, transplant your seedlings in June or July if you want to pick frost-kissed cabbages in mid-January.

Since cabbages don’t like hot weather, you may need to baby them as they transition to the hot summer weather. Keep the soil moist and watch for pests like aphids, harlequin bugs, and cabbage worms.

How to Grow

Detailed view of large, overlapping green leaves with deep veins and a slightly waxy texture.
It is easy to grow as long as you plant the crop at the right time of the year.

‘January King’ is easy to grow as long as you plant the crop at the right time of the year. It’s also important to keep an eye out for pests and diseases.

Light

A row of mature Brassica plants with tightly packed leaves and vibrant green heads, growing in soil during sunset.
You should plant them in an area that receives at least ten hours of bright, direct light each day.

These brassicas grow best in full sun. That means you should plant them in an area that receives at least ten hours of bright, direct light each day. It’s fine if your plants receive more light, but they may suffer if they receive less.

Water

Neatly spaced rows of small Brassica plants with two to four green leaves each, growing in a cultivated brown soil field.
You can irrigate using a watering can, hose, or automated drip irrigation system.

These cabbages require a moderate amount of water to remain healthy. The exact amount of water to apply varies depending on the soil type, temperature, air moisture, and mulch. However, you should expect to provide your crop with one to two inches of water per week.

Since wet foliage increases the chances that the plants will develop fungal diseases, apply water near the base of the plants. You can irrigate using a watering can, hose, or automated drip irrigation system. No matter which method you use, aim to keep the soil moderately moist.

Soil

A single plant with broad green leaves forming a tight head, growing in rich, moist soil. The outer leaves have a slight curl.
They grow well in clay, loam, and sand if the soil has good aeration, drainage, and proper nutrients.

‘January King’ cabbages grow best in well-draining soil rich in organic matter. The plants can grow well in clay, loam, and sand if the soil has good aeration, drainage, and proper nutrients.

If you notice your soil is compacted, loosen it before planting. There are multiple methods for aerating, but loosening the soil with a digging fork is an easy solution. Simply insert the tines of the fork into the ground, then pull the handle back until the soil cracks. Repeat this process every ten inches.

Temperature and Humidity

Multiple mature Brassica plants with tight heads and broad green leaves, growing in a well-maintained garden bed.
This brassica prefers cooler weather, especially as it matures.

Like most brassicas, this cabbage prefers cooler weather, especially as it matures. That’s one reason fall plantings are often more successful than spring crops.

As mentioned above, this variety is well known for its cold tolerance. Unprotected, it can survive temperatures as low as 5°F (-15°C), and a few layers of row cover help it tolerate subzero temperatures.

The plants prefer low humidity, but they can also tolerate moderate and high humidity. However, higher humidity makes the plants more likely to develop some types of diseases.

Fertilizing

A person wearing blue gloves sprinkling granular fertilizer around a small Brassica plant in dark soil.
Apply a balanced granular fertilizer with an NPK ratio of 10-10-10 at planting time.

Cabbage plants are heavy feeders that require a large amount of nitrogen to remain healthy. However, you should be careful to apply this nitrogen at the proper time. 

Adding a nitrogen-rich fertilizer like feather meal or blood meal during planting will provide the small plants with the nutrients they need to thrive. However, you should avoid applying nitrogen once the plants begin to mature since this can lead to problems with head formation.

These plants also require potassium, phosphorus, and micronutrients to remain healthy. Conducting a soil test is the best way to determine how much of these nutrients to apply. However, if you want to forgo a soil test, apply a balanced granular fertilizer with an NPK ratio of 10-10-10 at planting time.

Harvesting and Storage

A person in plaid clothing carefully lifting a large green Brassica head from the soil. The surrounding leaves are broad and vibrant.
Harvest by cutting the entire head near the ground.

Technically, you can harvest and eat cabbages in any state. However, you probably want to wait until the plants form dense heads. Harvesting mature heads allows you to enjoy the tender, crunchy leaves you dreamed of.

The days to maturity can help you determine when your plants are ready to harvest. Start checking the plants about five months after you plant the seedlings in the ground. Mature heads will be firm to the touch.

Harvest by cutting the entire head near the ground. You can easily strip off dirty or damaged leaves to reveal a beautiful cabbage head. However, it’s best to leave exterior leaves on the heads if you plan to store them in your refrigerator or root cellar.

While you can store ‘January King’ cabbage in cool conditions for a few months, remember that these plants also hold well in winter fields. That means you can leave the cabbages in your winter garden and harvest them when you need.

Common Problems

A Brassica plant with a round head, surrounded by leaves showing signs of holes, browning, and decay.
It is susceptible to various pests and diseases.

Unfortunately, ‘January King’ cabbage is susceptible to various pests and diseases. Knowing which common problems to look for can help you keep your plants healthy.

Pests

Close-up of cabbage worms, small green caterpillars with subtle stripes, feeding on cabbage leaves, causing irregular holes and damage to the green foliage.
Keep an eye out for them on maturing spring crops and summer-transplanted seedlings.

These cabbages are prime targets for many brassica pests. Most of these pests are more common in warmer weather, so keep an eye out for them on maturing spring crops and summer-transplanted seedlings.

Flea Beetles

Closeup of a flea beetle in a glossy blue color, sitting on a dried leaf.
Most flea beetle species are less than a quarter of an inch long and sport long antennae.

Flea beetles are a group of tiny, dark beetles that attack a range of vegetative crops. Most flea beetle species are less than a quarter of an inch long and sport long antennae. The pests can’t fly, but they hop when disturbed.

Flea beetles chew tiny holes in cabbage leaves. While a dozen flea beetles aren’t a big problem, these pests often appear in large numbers and shred plant leaves. They can be especially harmful to small seedlings.

One way to control flea beetles is to cover your plants with insect netting or lightweight row cover when planting time. This will exclude the pests from your crops. However, it’s important to note that flea beetles overwinter in the soil. Therefore, your plants may come under attack even if you cover them. If you notice flea beetles on your covered plants, remove the coverings and resort to other control measures.

If you experience a large flea beetle outbreak, you can spray the pests with neem oil, insecticidal soap, or pyrethrins. Make sure to always follow product instructions when applying these products.

Harlequin Bugs

Close-up of a beetle with a striking shield-shaped body featuring bold black and yellow markings, feeding on waxy leaves.
Both adults and nymphs feed on cabbage leaves using piercing and sucking mouthparts.

Although these shield-shaped bugs are beautiful shades of red, white, and black, they can seriously damage cabbage plants. Both adults and nymphs feed on cabbage leaves using piercing and sucking mouthparts. This feeding weakens leaves and makes the plants more susceptible to diseases.

You can control harlequin bugs by picking them off the plants. Make sure to remove the adults and nymphs and the round, black and white eggs. Other control measures include neem oil, pyrethrins, and insecticidal soap.

Cabbage Worms

A close-up of several small, green cabbage worms feeding on a large Brassica oleracea leaf, the damaged areas of the leaf showing clear holes and discoloration against the healthy green surface.
All of the larval forms of these pests feed on cabbage foliage and create irregular holes.

Cabbage worms are a group of caterpillars that feed on brassicas like the ‘January King’ cabbage. Some cabbage worms are small green caterpillars, and the cross-striped cabbage worm is a mix of gray, black, and yellow.

All of the larval forms of these pests feed on cabbage foliage and create irregular holes. Tiny cabbage worms can cause small holes, while larger caterpillars can create ragged leaves with large irregular holes. This damage can kill seedlings and severely damage older plants.

One way to control the pests is to remove the adults and eggs by hand. Check your plants at least twice weekly to keep up with the pests.

You can also spray your plants with Bt. This naturally-occurring bacteria stops the cabbage worms from feeding while leaving other insects unharmed.

Diseases

A Brassica plant with large green leaves showing visible holes and discoloration, likely from pest damage.
Most of these diseases can be prevented with cultural controls.

‘January King’ cabbage is susceptible to numerous diseases, but most of these can be prevented with cultural controls. Treatment is difficult once they take hold of your plant, so do your best to prevent them from occurring.

Black Rot

A budding purple Brassica oleracea head with tightly coiled leaves, nestled within broader green leaves that show infection of black rot.
The first symptoms are yellow leaf edges, which progress into brown or black leaves.

This bacterial disease impacts brassicas like ‘January King’ cabbage. The first symptoms are yellow leaf edges, which progress into brown or black leaves. The disease can lead to deformed cabbage heads and plant death.

Black rot can enter the garden via infected seeds, so make sure to buy your seeds from a trusted source that verifies seeds have been tested for the disease. Watering at the base of the plant also limits the spread of the disease, as does rotating brassica crops in your garden.

Once plants are infected, there is nothing you can do. The best option is to remove them to prevent the disease from spreading to other plants.

Alternaria Leaf Spot

Close-up of green Brassica leaves with small brown spots and slight yellowing around the edges. The surface is slightly glossy.
As the disease spreads, you may notice large patches of brown. 

This fungal disease causes round, brown spots on cabbage leaves. If you look closely, the spots consist of concentric circles. As the disease spreads, you may notice large patches of brown. 

Purchasing clean seeds, rotating brassica crops, and removing infected plants from your garden can help prevent alternaria leaf spot. It’s difficult to treat this disease once it appears, so remove infected plants to limit its spread.

Frequently Asked Questions

Can you eat ‘January King’ cabbage raw?

The tender leaves of ‘January King’ cabbage work well raw in sales and salads. You can also cook the cabbage leaves.

Is ‘January King’ cabbage a hybrid?

No. ‘January King’ is an heirloom cabbage with impressive cold tolerance.

Share This Post
A patch of small, smooth-leaved plants with rounded, slightly elongated leaves growing in dark soil, surrounded by healthy greenery from nearby plants.

Vegetables

13 Asian Greens You Should Plant This Season

Asian greens are popular worldwide tor their versatile flavor and rich nutrition. With quick-gorwing qualities and a preference for the cool season, now is the perfect time to plant the leafy culinary stars for prolific yields. Join gardening expert Katherine Rowe in exploring favorite crops with wide appeal.

A close up shot of various harvested tubers, that you can grow root vegetables

Vegetables

13 Delicious Root Vegetables You Should Grow This Year

What better way to embrace the full potential of your garden than growing root vegetables? These underground vegetables pack a delicious and nutritious punch. Join gardening expert Liessa Bowen on a tour of some familiar and some lesserknown root veggies you can grow in your own garden!

Close-up of a hand in a pink glove harvesting cauliflower in a sunny garden.

Vegetables

How and When to Harvest Cauliflower in the Fall Garden

Autumn weather causes green cauliflower stems to start forming their white sprouts—you’ll see your plants turn from leafy seedlings to bulging heads! Fall is perfect for growing cauliflower since the cool temperatures promote healthy head formation with little riciness or bolting. Join backyard grower Jerad Bryant and learn how to harvest your ready crop!

Close-up of a gardener's hand harvesting broccoli, revealing dark blue-green leaves with prominent veins fanning out around a dense, central cluster of tightly packed green buds.

Vegetables

How and When to Harvest Broccoli for the Tastiest Crop

Broccoli is a tasty, tender crop with lots of nutrients. It’s perfect for backyard gardens! You may wonder when it ripens, and when you should harvest its heads. Wonder no more, since we’ll discover when and how to harvest your growing veggies. Learn to cut your broccoli heads in this guide alongside seasoned grower Jerad Bryant.