Growing cabbage in home gardens
A quick guide to cabbage
- Grow where you have not grown cabbage, broccoli, cauliflower, turnips, rutabaga or Brussels sprouts for the last four years.
- If you will plant it in the spring for summer harvest, you should start cabbage indoors. For a fall crop, plant seed directly in the garden in early July.
- Cabbage will not have good yield and quality unless the plants can take up water and nutrients throughout their growth.
- Cabbage will tolerate below-freezing temperatures late in plant growth.
Cabbage (Brassica oleracea, Capitata group) is a member of the mustard family, and like most related crops, grows best in cool weather. The crop has spherical, flattened or pointed heads made of leaves that wrap around each other tightly. In the center of the head is a short, thick stem or “core.”
Cabbage has many uses in Minnesota kitchens. Raw, it brings crunch and zest to salads and slaw. You can braise, stir-fry, stuff, add to soups, mix into the filling for egg rolls, and ferment cabbage to make sauerkraut and kimchi.
In Minnesota, gardeners typically plant cabbage in spring for a summer crop, and then again in mid-summer for a fall crop.
Soil pH and fertility
- Have your soil tested.
- Apply phosphorus (P) and potassium (K) according to soil test recommendations.
- Many Minnesota soils have adequate amounts of phosphorus.
- Unless your soil test report specifically recommends additional phosphorus, use a low- or no-phosphorus fertilizer.
- Grow cabbage in well-drained yet moisture-retentive, fertile soil with a pH of 6 to 7.
- Improve your soil by adding well-rotted manure or compost in spring or fall. Do not use fresh manure as it may contain harmful bacteria, and may increase weed problems.
- The plant needs to absorb water and nutrients steadily during its growth.
- Do not use any fertilizer containing a weed killer ("Weed and Feed"), as it may kill your vegetable plants.
- When the plants are about 4 inches tall, apply fertilizer alongside the row of plants at a rate of ½ cup of 46-0-0, or 1 cup of 27-3-3, or 3-½ cups 10-3-1 for each 100 feet of row.
- Spread the fertilizer in a six-inch wide band, and scratch it into the surface of the soil.
- If you use manure or compost, you may not need additional fertilizer applications, depending on how much organic matter you apply.
Start cabbage indoors if you will plant it in the spring for a summer harvest. Although the seeds will germinate at low soil temperatures, cabbage seedlings are sensitive to frost. If you wait until the weather has settled, and plant the seeds later in spring, the crop will mature during the hottest part of the summer, leading to poor quality.
There is no need to use a heating mat as you might for other seeds. Normal room temperatures between 60°F and 70°F, and bright overhead light, will lead to the best development of the plants. Higher temperatures cause rapid growth, producing tall, weak plants that are difficult to handle without causing damage.
- Start seeds indoors in early April, or four to six weeks before transplanting. Leave 24 to 30 inches between hand-cultivated rows, and 18 inches between plants. Per 20 feet of row, you should order one seed packet, or 12 plants.
- Plant the seeding at a depth of 1/4 of an inch.
- Apply fertilizer to developing seedlings beginning when the first true leaf appears. Use a half-strength starter solution once a week. After two true leaves are present, apply fertilizer twice a week.
- When the plants have five true leaves after about three weeks, reduce watering.
- Place plants outside where they will receive a couple of hours of sunlight and have wind protection.
- Slowly expose them to more sunlight over the next week or two, bringing them indoors if night temperatures drop below 40°F.
- Dig small holes with a trowel, or dig a furrow with a shovel.
- Place the seedlings 15 to 18 inches apart, and fill the soil around them so that the plant is at the same level it was in its pot.
- Water the plants in, or use a transplant starter solution high in phosphorus, and low in nitrogen and potassium.
For a fall crop, plant seed directly in the garden in early July. It is impossible to know just when cold weather will come, but in most of Minnesota, you must harvest cold-tolerant crops like cabbage by late October.
Cabbage takes between 60 and 100 days to mature. A July planting will begin to form a head as summer turns to fall, and be ready to harvest before a hard freeze. Direct seeded cabbages will take up to three weeks longer to reach maturity than transplants, so for much of Minnesota, the first week in July is the right time to plant.
- Plant seed shallowly at a depth of 1/4 to 1/2 inch, and three seeds every 15 to 18 inches.
- Keep the soil moist during emergence. Once the plants emerge, thin so that one seedling remains.
- You will need to take particular care of the seedlings, as they experience extreme heat, wind, drought, and insects when they are most vulnerable. Water them as needed.
- A row cover will protect the plants from wind and insects during the first weeks of growth.
How to keep your cabbage plants healthy and productive
- Cabbage needs good soil moisture. The best quality heads are firm, crisp, juicy, sweet, and sometimes peppery, but without bitterness.
- If the plants do not receive consistent rainfall or irrigation, they will have poor texture and excessive bitterness. Outer leaves may brown and dry up, or the plant may fail to form a head.
- One inch of rainfall per week is enough water.
- If your soil is sandy, it is better to water more often than once a week.
- An inch of water will wet a sandy soil to a depth of ten inches, a heavy clay soil to six inches.
- Use a trowel to see how far down the soil is wet. If it is only an inch or two, keep the water running.
- Frequent, shallow cultivation will kill weeds before they become a problem.
- Cultivate just deeply enough to cut the weeds off below the surface of the soil. Be careful not to damage the plants when cultivating.
- Mulching with herbicide-free grass clippings, weed-free straw or other organic material to a depth of three to four inches can help prevent weed growth, decreasing the need for frequent cultivation.
For assistance in diagnosing unknown problems, visit the University of Minnesota Extension diagnostic site “What’s wrong with my plant?”
Damage to the central growing point when the plant is small can cause failure to form a head. The leaves that have already formed will become tough and thick, and no further leaves will develop.
Cold temperatures, rough handling or insect feeding can all damage the growing point of young plants, so be careful when handling them and when working around them. Do not set plants out before the weather has settled. Look for insect infestation.
- Harvest cabbage when the heads reach a usable size. To harvest, cut the head off above the outer leaves.
- Once the heads reach their mature size, there is a risk that they will split before harvest. Some varieties are good for “field holding” and are less likely to split. Heavy rain can cause split heads.
- You can minimize splitting of cabbages that you are not ready to pick by twisting the head a quarter turn or shearing one side of the roots with a spade. This action reduces water flow into the head.
- Cabbage will tolerate below-freezing temperatures late in plant development. If overnight temperature lows are below 25°F, you can protect the heads with a row cover.
- Cabbages can last for months, but only in cold, moist conditions: 32°F to 40°F and 95% humidity. This is colder and much moister than a refrigerator, and difficult to achieve for most home gardeners.
- If you want to store cabbage, you will need a root cellar.
- A time-honored way of preserving the cabbage harvest is fermentation. The European version is sauerkraut. The traditional Asian fermented cabbage is kimchi.
Reviewed in 2018