Cabbage Leaves Turning Brown? [Causes & Cares]

Growing cabbages can be a fun and rewarding experience. It’s a great way to get fresh, healthy produce right in your own backyard.

However, when cabbage leaves start turning brown, it can be frustrating and downright confusing if you can’t figure out why it’s happening.

Cabbage leaves turn brown due to inadequate water intake caused by calcium deficiency, too much exposure to the sun, or pests and diseases. Additionally, their leaves will naturally turn brown and wilt as cabbages mature. Proper care will help ensure your cabbage plants stay healthy and thriving.

The rest of this comprehensive guide will explore the most common causes of browning cabbage leaves, how to prevent the phenomenon, and what to do if your cabbages are already experiencing this issue.

I will also offer expert tips on growing healthy and robust cabbages. Read on to learn everything you need to know about keeping your cabbage leaves green and lush.

Copenhagen Market Early Cabbage Seeds, 300 Heirloom Seeds Per Packet, (Isla's Garden Seeds), Non GMO Seeds, Botanical Name: Brassica oleracea

Also read: Should I Cut Off Brown Hydrangea Blooms?

Causes of Browning Cabbage Leaves

  • Browning leaves are one of the most upsetting and perplexing problems when growing cabbages. When left unchecked, browning leaves can quickly turn your project into a disaster.
  • However, don’t fret just yet! In most cases, browning leaves are easily fixed with a little bit of extra care and attention.

Common causes of cabbage leaves turning brown are:

  1. Inadequate water intake
  2. Too much exposure to the sun
  3. Pests and diseases
  4. Natural wilting due to maturity

I’ll be taking a closer look at each of these causes below.

Inadequate Water Intake

Inadequate water intake is one of the most common reasons cabbage leaves turn brown. Cabbages are heavy feeders and require a consistent water supply, especially during hot summer days. Their leaves will wilt and turn brown if they don’t get enough water.

However, inadequate water intake doesn’t occur due to insufficient watering or irrigation techniques. Instead, it’s caused by a calcium deficiency in the soil.

Calcium is an essential mineral for healthy plant growth. It helps with cell division and strengthens plant tissues, including the delicate leaves of cabbage plants. When calcium levels are low, the water uptake is inhibited, and leaves will start to wilt and turn brown.

To improve water intake and prevent browning leaves, you must maintain adequate calcium levels in the soil.

Here are several ways to do that:

  • Add lime to the soil: This is the most common and effective way to raise calcium levels. Lime raises the soil’s pH and makes calcium more available to plants.
  • Apply compost or manure: Both compost and manure contain high levels of calcium and other essential nutrients. They help improve soil quality and increase water retention.
  • Foliar spray: Foliar spraying is a method of applying nutrients directly to the leaves. It’s an effective way to quickly raise calcium levels in plants.
  • Apply a calcium-rich fertilizer: Calcium fertilizers release calcium slowly over time and are an excellent way to maintain adequate calcium levels in the soil.
  • Bone meal: A high-phosphate fertilizer, bone meal is an excellent way to raise calcium levels and promote healthy plant growth. However, it can also increase the soil’s pH level, so use it with caution.

Before adding calcium to the soil, it’s crucial to do a soil test to determine existing calcium levels. This will help ensure you add the right amount and avoid raising the soil’s pH level too much. You can test with a simple kit from your local garden center or hire a professional soil testing service.

Cabbage Seeds for Planting 5 Individual Packets Bok Choy, Michihili (Napa) Chinese Cabbage, Red, Golden Acre and Copenhagen Market Early for Your Non GMO Heirloom Vegetable Garden by Gardeners Basics

Have a look: Hydrangea Turning Brown? [Reasons & Cares]

Too Much Exposure to the Sun

  • Cabbage plants need full sun to thrive, but too much sun can be just as damaging as too little. High heat levels and intense sunlight increase evaporation rates and cause the leaves to wilt and turn brown. Due to heat stress, the plant’s growth will be stunted, and the leaves will become dry and crispy.
  • Suppose you live in areas that experience high temperatures like Georgia, South Carolina, or Louisiana. In that case, you may need to provide shade for your cabbage plants during the hottest hours of the day. You can do this by erecting a shade cloth over the plants or by planting them under taller plants that will provide natural shade.
  • Water the plants regularly and deeply to help them withstand the heat. Mulching with straw or hay will also help reduce evaporation and keep the roots cool. Avoid watering the leaves directly as this can promote fungal diseases.

Pests and Diseases

Pests and diseases are other common causes of browning cabbage leaves. Due to their lush greenery, cabbage plants are susceptible to various pests and diseases, including aphids, whiteflies, and black rot.

  • Aphids are small, sap-sucking insects that feed on the leaves of cabbage plants. They use a sharp beak to pierce plant leaves and suck out the sap. Aphids excrete a sticky substance known as honeydew, which attracts other pests and promotes the growth of sooty mold.
  • Whiteflies, like aphids, are tiny insects that feed on the sap of cabbage plants. Their feeding causes the leaves to turn yellow and brown and eventually die. Whiteflies also excrete honeydew, which can lead to sooty mold growth.
  • Black rot is a fungal disease that affects cabbage plants. The disease starts as small, black lesions on the leaves, which eventually expand and turn the leaves brown. The lesions eventually cause the leaves to die and fall off the plant.

Start with healthy seedlings and practice good gardening hygiene to prevent pests and diseases from damaging your cabbage plants.

Be sure to clean up debris and fallen leaves from around the plants and remove any affected leaves as soon as you notice them. You can also treat your plants with organic pesticides and fungicides to help prevent damage.

Copenhagen Market Early Cabbage Seeds, 300 Heirloom Seeds Per Packet, (Isla's Garden Seeds), Non GMO Seeds, Botanical Name: Brassica oleracea

Check out: Philodendron Selloum Soil Mix

Natural Wilting Due to Maturity

  • As your cabbage plants mature, they will naturally wilt, and the leaves will turn brown. This is perfectly normal and is not a cause for concern. Once the cabbage heads mature, you can harvest them and enjoy your delicious homegrown cabbage!
  • Regularly remove the browning leaves from the plant to encourage new growth. You can also water the plants more frequently to help keep them hydrated and prevent wilting.
  • Add the browning leaves to your compost pile or use them as mulch around other plants. However, carefully inspect them for pests and diseases to avoid spreading the problem.

Expert Tips on Growing Healthy and Robust Cabbages

Healthy crops are every gardener’s dream, and following these simple tips will help you grow robust and thriving cabbage plants:

Start With High-Quality Seedlings From a Trusted Nursery

  • The key to growing healthy cabbage plants is to start with high-quality seedlings from a trusted nursery. Avoid buying leggy seedlings, ones that have yellow or brown leaves, or are otherwise looking unhealthy.
  • These seedlings are more likely to be stunted in growth and will be more susceptible to pests and diseases. Instead, choose seedlings that are dark green and have healthy-looking leaves.

Choose the Right Variety for Your Climate

  • Cabbage does well in a cool and moist climate, so choose a variety that is suited for your particular environment. Choose a heat-resistant variety if you live in an area with warm winters and hot summers.
  • For regions with cool summers and cold winters, choose a variety tolerant of frost. This will help your plants to thrive and prevent them from getting damaged by extreme weather conditions.

Read: How Fast Does An Areca Palm Grow

Plant the Seedlings in Well-Drained Soil

  • Cabbage plants thrive in deep, well-drained soil. The soil should be rich in organic matter and have a pH between 6.0 and 7.0.
  • If your soil is too sandy or clayey, you can amend it with compost or peat moss to improve drainage. Waterlogged soil can lead to root rot, so be sure that the soil drains well.

Fertilize the Plants Regularly

  • Frequent and adequate fertilization is essential for healthy cabbage plants. Use a balanced fertilizer that is high in nitrogen and low in phosphorus. Apply the fertilizer every 4 to 6 weeks throughout the growing season.
  • Do a soil test before fertilizing to determine the nutrient levels in your soil and adjust the feeding schedule accordingly.

Copenhagen Market Early Cabbage Seeds, 300 Heirloom Seeds Per Packet, (Isla's Garden Seeds), Non GMO Seeds, Botanical Name: Brassica oleracea

Water the Plants Regularly

  • Water your cabbages frequently to keep them vibrant and healthy. The soil should be moist but not waterlogged. Be sure to water the plants early in the day, so the leaves have time to dry off before nightfall.
  • This will help to prevent fungal diseases from developing. Add a layer of organic mulch around the plants to help retain moisture and keep the weeds at bay.

Control Pests and Diseases

  • When left unchecked, pests and diseases can quickly destroy your cabbage plants. Regularly inspect your plants for pests or diseases like black soot, yellowing leaves, or stunted growth.
  • If you notice any of these problems, take action immediately by using organic pesticides or beneficial insects. Moreover, make sure to destroy any infected plants. Keep your garden free of debris and weeds to help prevent the spread of pests and diseases.
Cabbage Leaves Turning Brown
Cabbage Leaves Turning Brown

Also, you may like some more below Gardening articles:

Final Thoughts

  • Cabbage leaves turning brown is a common problem most gardeners face. Unless caused by the natural aging process of the plant, brown leaves are often indicative of a pest or disease problem.
  • Inadequate water intake, too much sun exposure, or nutrient deficiencies can also cause browning leaves. Boost calcium levels in your soil and water the plants regularly to ensure robust and healthy plants. Inspect the leaves regularly for pests and diseases and take action immediately if you find any problems.