My cabbage leaves are turning yellow – why? How can I save them?

Cabbage

As soon as the plant's appearance changes and becomes unnatural, it's time to sound the alarm, as this could indicate the onset of potential diseases. Some cabbage diseases can be dangerous, so don't ignore them.

When cabbage leaves start to turn yellow, you first need to find out the underlying cause and then take action.

The main causes of yellowing leaves

There are several reasons why cabbage leaves turn yellow and wilt. The main ones include:

problems in agricultural technology;
failure to comply with crop care rules;
diseases;
viruses and pests.

Problems in agricultural technology

Although cabbage isn't particularly demanding in terms of care, it's important to know and follow basic care guidelines. However, there are challenges with cultivation techniques related to the following factors:

Insufficient nitrogen in the soil. Nitrogen is essential for the firmness of the head and the growth of the vegetable. Without it, the cabbage leaves begin to turn yellow, and eventually, the plant dies completely. Nitrogen deficiency occurs due to crop rotation issues, where the same crop is planted in the same spot for several years, resulting in poor soil quality.
Insufficient phosphorus. Plants depend on it for growth and development. Phosphorus also regulates protein synthesis. If cells don't divide properly, the plant won't achieve its desired shape and volume.
Insufficient magnesium. It helps the root system develop. A sign of magnesium deficiency is pale leaves.

Important!

If the soil is too acidic, no mineral fertilizer will help. Lime must be added first.

Failure to comply with crop care rules

A common cause of yellowing cabbage leaves is insufficient sunlight. Therefore, it's important to choose your future garden bed wisely. However, a well-lit area isn't always ideal for growing and thriving cabbage. There are other signs of yellowing:

The soil type is not suitable for growing cabbage. The plant will not thrive in sandstone.
Incorrect watering. If the plant is underwatered, it will develop a sickly yellowish tint, and the leaves will wilt and die. Overwatering can lead to root rot.
Severe drought in a hot summer.
Spring frosts. Sudden temperature fluctuations during the day and night prevent plants from developing and growing properly.
Insufficient loosening of the soil, resulting in poor absorption of nutrients by the root system.

Diseases

Diseases occur as a result of infection or fungal attack. These two types of diseases are dangerous for cabbage, as they can destroy the entire crop. Diseases that cause yellowing of leaves are listed in the table:

Disease	Type of disease	Signs and symptoms
Kila	Fungal infection	A dangerous disease that attacks the plant's root system. Growths and hardening of the roots occur, robbing the plant of all its beneficial nutrients.
Fusarium wilt	Fungal infection	It develops while the seedlings are still growing. When affected by the fungus, the lower part of the cabbage turns yellow, wilts, and dies. Brown spots will be visible when the stem is cut.
Peronosporosis	Infection	This disease is also known as powdery mildew. It most often appears when planting seedlings in open ground. The leaves dry out and become covered with yellowish spots on the top and a gray coating on the bottom.
Blackleg	Infection	Seedlings are most often affected. The infection turns the roots waterlogged, which eventually darkens and rots. The leaves dry out and turn yellow.
Mucous bacteriosis	Bacterial infection	The disease affects the entire plant, first attacking the stalk. It becomes soft and turns creamy yellow. The leaves gradually rot and fall off.
Gray rot	Fungal infection	When affected by gray mold, the leaves begin to turn yellow on top, and a gray coating appears on the lower part of the head.
Vascular bacteriosis	Bacterial infection	It appears as black rings on the plant's vessels. After the vessels blacken, the leaves are affected—they turn yellow at the edges and then fall off.

Viruses and pests

Cabbage is susceptible to pests that eat the plant's root system or stem. Yellowing of leaves can be caused by cutworms, cockchafers, aphids, cabbage white butterflies, or mole crickets. Therefore, if the color of cabbage leaves changes, carefully inspect the underside of the plant.

Methods for combating yellowing

To determine the cause of yellowing and prevent it, you need to do the following:

A thorough examination of the plant and the surrounding soil. You can remove a single plant from the ground and carefully examine its root system, as well as observe how the sun illuminates the cabbage and the temperature conditions under which it grows;
Enriching depleted soil. Chicken manure or urea will help saturate the soil and plants with nitrogen, and nitrogen-phosphorus nutrition will replenish phosphorus deficiency;
Establishing irrigation to avoid soil drying out and oversaturation with moisture.

If the plant is infested by pests or diseases, sprinkle the plant with wood ash or sprinkle red pepper on the stem. Spraying the bush with a valerian solution will help get rid of caterpillars.

If a fungal disease occurs, the bush should be completely destroyed and the soil treated with copper sulfate in a ratio of 10:5 (liters of water to grams of solution). To prevent infection, it is recommended to disinfect the seeds and soil with copper sulfate beforehand.

Recommendations and advice

To get a good cabbage harvest, simply follow these recommendations:

Diseased seedlings should not be planted outdoors. This can contaminate the soil, and the fungus can survive in the soil for several years. Yellowed plants should be completely dug up and destroyed.
Enrich the soil with lime (1 kg per 4 m2).
Regulating soil moisture by watering correctly.
Maintain crop rotation. It is not recommended to plant cabbage in the same area.

To prevent pest attacks, thoroughly till and loosen the soil in the fall, and burn any plant debris left after harvest. To ensure rapid adaptation, the plant should be planted in early spring. This will allow the seedlings to develop sufficient strength. Covering the crop with plastic will protect it from early frosts.

Conclusion

Yellowing leaves can be caused by improper care, as well as disease and pest infestation. To prevent this, it's recommended to follow the advice and grow the plant correctly. Timely preventative measures will reduce the likelihood of pest or disease damage. Prevention should begin with the seeds.

Reviews

Oleg

Last season, when planting cabbage outdoors, I encountered powdery mildew. It was very difficult to combat, but after a long time, I was able to do so. Treating the plants and soil with copper sulfate helped, at a rate of 2.5 grams per 5 liters of water. This season, I pre-treated the seeds with copper sulfate to disinfect them from the very beginning.

Valentina

I've been planting hybrid cabbage varieties for two years now, and each time I've had a bountiful harvest. Regular varieties are highly susceptible to various diseases that affect cruciferous vegetables. The hybrid variety is immune to these diseases, so it's not susceptible.