Agronomy

Description

A cool-season crop, cabbage can grow during spring and fall seasons. It belongs in the mustard family. Cole crops and crucifer crops are alternative names for crops like cabbage and its relatives such as broccoli, brussels sprouts, cauliflower, kale and collards. Although classified as a biennial, cabbage grows as an annual vegetable crop. Cabbage crops can tolerate cold conditions, and during warm conditions, cabbage may flower earlier than expected. This response is called bolting.

Site Selection

Cabbage can acclimate to multiple soil conditions, including silty clay soils that poorly produce other crops. However, it prefers well-drained planting sites. Cabbage also likes areas that provide high organic matter. The desired soil conditions may vary by season. For example, if growing cabbage during early spring, then light, sandy soils will warm quickly, but moisture and nutrients may leach from these soils to a greater extent. If planting later in the year, then heavier soils prone to holding water may be preferable.

Adhere to an adequate crop rotation. Within the past two years or three years, a particular planting site shouldn’t have grown broccoli, collards, cabbage or other related cole crops. Consider rotating with crops from the Cucurbit and Solanaceaous families. Rotating crops can reduce disease and pest pressure. Also, choose planting sites with 6.0 to 6.5 soil pH levels. If the intended planting site doesn’t have its soil pH level within this range, then make the necessary adjustments.

Fertility

To supply nitrogen, phosphorus and potassium at levels needed for cabbage production, ensure that plants will have 120 pounds of each macronutrient. During the growing season, cabbage growers can test cabbage tissue and sap to determine whether the fertilizer plan requires refinement.

Relative to other vegetables, cole crops like cabbage have high boron requirements. Without adequate boron, cabbage can develop a “hollow heart,” characterized by cracking and browning in the center of the cabbage head. For each ton of fertilizer, add 10 pounds to 20 pounds of Borax to avoid these issues.

During early growth, cabbage has high nitrogen requirements. Twice during the growing season, sidedress applications can supply needed nitrogen. The first sidedress application should occur two weeks after transplanting or four weeks to five weeks after directly seeding cabbage, and the second application should occur three weeks later. In both cases, the sidedress application should range from 20 pounds to 25 pounds of nitrogen.

Variety Selection

Available cabbage varieties are predominantly hybrids. Cabbage varieties can produce cabbages typified by several characteristics: head size, shape, color and leaf texture. Cabbages may produce small or large heads. Cabbage varieties may also have differing wrapper leaf structures and core lengths. When supplying the processing market, growers usually choose varieties that produce larger cabbages. Possible cabbage shapes are round, flat-round, conical or another size variation. From a color perspective, growers can choose from green, blue-green or red varieties, and leaf textures can be classified as smooth or savoy. Assess local market needs before selecting varieties. Buyers should seek characteristics of the selected varieties. The following table shares cabbage varieties listed in the Midwest Vegetable Production Guide for Commercial Growers.

Growing season – spring or fall – may also influence variety selection. Bolting susceptibility can vary by variety. Additionally, disease and physiological condition resistance or tolerance can differ by variety. Some varieties may resist black rot, downy mildew, Fusarium yellows and tipburn. Yield would be another factor to consider when selecting cabbage varieties.

Recommended Cabbage Varieties

Planting

Producers can choose to grow cabbage from seed or transplants. They tend to frequently use transplants, however. Growing cabbage from transplants can add costs, but the transplants also offer benefits. When planting transplants, container-grown transplants may be preferable. Any transplant used should be hardened. In hardened cabbage seedlings, outer portions of their leaves may display purple coloring. Additionally, cabbage transplants should be young and grow quickly. When planting transplants, cover the whole root ball, and apply a starter fertilizer at planting. The starter solution should supply macronutrients at roughly a 1 nitrogen: 3 phosphorus: 0 potassium concentration. Typically, each plant requires half of a pint of starter solution.

When directly seeding cabbage, note that weed control may be challenging, the seedbed requires a level surface, planting equipment must achieve the ideal planting depth and spacing, and crop earliness potential may be limited. Before planting, consider treating seed in a hot water bath to decrease incidence of some diseases, though germination rate may decline with the treatment. The hot water bath should expose seed to 122 degree F temperatures for 25 minutes. Then, cool the seed in a cold water bath. If producers decide to grow cabbage from seed, then wait to plant until soil temperatures warm to 40 degrees F for seed to germinate. Temperatures from 45 degrees F to 95 degrees F promote good germination. Although cabbage crops can withstand hard frosts, they’re susceptible to severe freezes.

Seed planting depth may range from 0.5 inches to 0.75 inches. In-row spacing may range from 6 inches to 9 inches. To grow larger cabbage heads, allocate more in-row spacing. If using double rows, then increase the spacing to 12 inches to 14 inches. Double rows may boost yields by 30 percent to 50 percent. They have this effect as they reduce weed concerns and support crop uniformity. For cabbage plantings, space rows every 36 inches.

When planting cabbage, several other practices, such as laying plastic mulch and forming raised beds, may be considered. With plastic mulch, soils may warm more quickly, and moisture levels can be preserved. Other plasticulture benefits include reduced soil compaction and crusting, minimized fertilizer leaching, limited weed competition and decreased crop drowning. It also keeps wrapper leaves clean. Manage plasticulture production costs by planting a second crop and using the same mulch. In raised beds, the soil may warm more quickly, and the raised feature enhances drainage. However, during dry weather, irrigation would become more critical in raised beds.

Cultural Management

To extend the cabbage growing season, producers can adopt several practices. These include selecting a planting site with southern exposure, adding row covers to form a microclimate, laying plastic mulch and installing windbreaks.

Water Management

Cabbage has some drought tolerance, but it still requires sufficient moisture to yield well. It is a crop that grows fast and has shallow roots. As such, using irrigation is a good practice. Without adequate moisture after planting and as cabbage heads develop, cabbage may suffer lower yields, and heads can experience growth cracks or tipburn.

Weed Control

Weeds can have several negative effects in cabbage production. For example, they may vie for production resources, including light, water and nutrients. With weeds present, insect pressure and disease risk may also increase. When producing cabbage early, the crop may establish itself before annual weed pressure develops into a challenge.

If weeds are a problem, then early control is critical for cabbage production. Control options are varied. Mechanical cultivation and plasticulture production can minimize weed pressure. Chemical applications also typically work well. Alternatively, by rotating crops and preparing a stale seedbed, producers may address weeds. Creating a stale seedbed involves preparing the seedbed, enabling weeds to emerge, spraying nonselective herbicides and planting the cabbage crop. During planting, producers should make an effort to avoid disturbing too much of the planting area. Operations may also remove weeds by hand.

Insects and Diseases

For cabbage producers, insects often represent a significant production challenge. Insect pressure typically intensifies as the year progresses. In other words, anticipate that insects would present a more significant problem in fall crops than spring crops. Insect pressure can be especially economically damaging during the seedling and head formation stages. Pests create marketing issues when they have damaged the cabbage head or wrapper leaves. Cutworms, imported cabbage worms, cabbage loopers, diamondback moth larvae and cross-stripped cabbage worms all may target cabbages. Aphids and flea beetles are other insects that may affect cabbage. Root-knot nematodes may also target cabbage.

To limit crop damage, regularly scout whether insects have infected cabbage fields. Routine scouting will help to develop a pesticide application schedule and address insect issues early. Weekly scouting is preferable. Rotating crops can address pest management.

From a disease perspective, several can affect cabbages and possibly decrease yields. Such diseases include black rot, Fusarium yellows and downy mildew. To reduce disease risk, adopt practices such as rotating crops, choosing disease-resistant or -tolerant varieties, eradicating cruciferous weeds and applying fungicides or bactericides. Several viruses may also afflict cabbages, including the turnip mosaic virus, cabbage mosaic virus and tomato spotted wilt virus.

Cabbage can also be susceptible to tipburn, which is a physiological condition. A calcium deficiency, low soil pH level, high relative humidity levels and overfertilization-related quick growth can contribute to tipburn. Prevention strategies include choosing tolerant varieties, applying fertilizer at the correct rates, adjusting the soil pH level and supplementing calcium levels as necessary. For cabbages experiencing tipburn, they won’t have marketability.

Harvest and Storage

Cabbage production relies on hand harvesting. For most varieties, cabbage heads will mature within 60 days to 100 days after sowing. Depending on the variety, cabbage may require one harvest or two harvests at most, but others may require more than three harvests. Cabbage head compactness determines the extent of cabbage maturity. If a cabbage has loose compactness, then it hasn’t matured enough for harvesting. At maturity, the cabbage should feel very firm or hard. It should also have crisp, turgid leaves. A market-ready cabbage generally weighs roughly 2 pounds to 2.5 pounds.

At harvest, cut stems near the ground and cabbage head base. Remove all but three to six wrapper leaves. The stem should measure one-half inch or less between the end of the stem and the outer leaves. Longer stems could damage other cabbages during handling.

To prevent wilting, avoid placing cabbages in the sun after harvest. Cabbages are susceptible to sun blister. After harvest, examine cabbage heads for yellowed, brownish or damaged leaves, and trim such leaves from cabbages. Attempt to prevent cabbage leaves and heads from being cut or broken to avoid wilting and pathogen contamination.

As mentioned earlier, bolting may occur if susceptible cabbage varieties are exposed to temperatures warmer than 75 degrees F. Other than temperature changes, additional conditions that could facilitate bolting include nitrogen deficiency; inadequate concentrations of other nutrients; and weed, insect and disease pressure. In all cases, these conditions would contribute to reduced vegetative growth. During bolting, the plant starts to channel resources toward reproduction rather than focus specifically on vegetative growth. If a cabbage head has seed stalks showing, then it loses marketability.

To store cabbages, generally choose a storage area that maintains 32 degree F temperatures, but 31 degree F temperatures may work best for late-crop cabbages. If storage temperatures drop lower than 30.4 degrees F, then cabbage heads may develop a freezing injury. During storage, the relative humidity level must exceed 95 percent. Storage life varies depending on whether cabbages are early-crop or late-crop cabbages. On average, storage life may range from three weeks to six weeks for early-crop cabbages and as long as six months for late-crop cabbages. When stored for long periods, growers may need to remove many outer cabbage leaves if they have deteriorated. Stem or seed stalk growth, root growth, internal breakdown, leaf abscission, discoloration, decay and black speck are deterioration signs. Avoid storing cabbage with crops that release ethylene because cabbage is sensitive to this compound.

 Sources

Cantwell, Marita and Trevor Suslow. 2001. Cabbage (Round & Chinese types): Recommendations for Maintaining Postharvest Quality. University of California. Davis, CA 95616.

Coolong, Tim, W. Terry Kelley, Greg MacDonald and David B. Adams. Commercial Production and Management of Cabbage and Leafy Greens. University of Georgia. Athens, GA 30602.

Daugovish, Oleg, Michael Cahn, Steve Koike, Eric Natwick, Marita Cantwell and Etaferahu Takele. 2008. Cabbage Production in California. University of California. Oakland, CA 94608-1239.

Delahaut, K.A. and A.C. Newenhouse. 1997. Growing broccoli, cauliflower, cabbage, and other cole crops in Wisconsin. University of Wisconsin. Madison, WI 53703.

Kaiser, Cheryl, Matt Ernst and Tim Coolong. 2011. Cabbage. University of Kentucky. Lexington, KY 40506.

Kemble, J.M., G.W. Zehnder, E.J. Sikora and M.G. Patterson. 1999. Guide to Commercial Cabbage Production. Alabama Cooperative Extension System. Centreville, AL 35042.

Midwest Vegetable Production Guide for Commercial Growers. 2016. Midwest Vegetable Production Guide for Commercial Growers.

Sanders, Douglas. 2001. Cabbage. North Carolina Cooperative Extension. Raleigh, NC 27695-7602.