Why did cabbage leaves turn purple and what to do about it?

Cabbage is a healthy vegetable that is found in almost every summer cottage. It is unpretentious in care and, subject to growing rules, produces a rich harvest. However, it happens that its leaves turn blue or acquire a purple tint. This article will help you understand the causes of the problem and how to fix it.

Why do cabbage leaves turn purple?

The usual white leaves with a greenish tint may change color to blue or purple for the following reasons:

1. Nitrogen deficiency. At the same time, not only the color of the leaves changes, but the development of heads of cabbage is also suspended. Most often, early varieties suffer from this in the spring, when, due to rainy weather, the vital activity of soil microflora decreases, and nitrogen reaches the seedlings in small quantities.
2. Lack of phosphorus. In addition to the appearance of a purple color, there is a decrease in the volume of leaves and a slowdown in the development and formation of forks.
3. Stress of seedlings when transplanted into open ground. This temporary phenomenon disappears within 7-10 days.
4. Sudden temperature changes, frosts and cold snaps. This happens if the seedlings were not hardened by being outdoors or were transplanted into soil that was not heated to the required minimum (+14...+16°C).
5. Insufficient watering or waterlogging of the soil. Cabbage loves water, but if there is too much water, the foliage darkens, the roots rot, and the plant dies. Dry soil over a long period of time causes leaves to become dry, hard, and blue in color.
6. Manifestation of fungal disease blackleg, from which cabbage is not protected at any stage of development. Due to damage to the root system by the fungus, the nutrition of the plant is suspended, which affects the color of the leaves and leads to the death of the cabbage.
7. Manifestation of clubroot. Signs of this disease are blue leaves and wilting of the plant, most noticeable at midday. Growths form on the root system, blocking access to nutrients.
8. Pests, in particular aphids and cabbage flies. While aphids are easy to spot, cabbage fly larvae are located in the stems of the plant and gnaw entire tunnels inside the cabbage.

The quality and quantity of the harvest largely depends on the preparation of the seedlings. Do not neglect hardening and plant strong, healthy shoots in the ground without damage or signs of fungal diseases.

What to do if cabbage has purple leaves

Most often, a change in the greenish color of the foliage to purple is a signal for the need to take measures to eliminate negative factors.

Top dressing

If the weather conditions outside are comfortable, and during an external examination no traces of disease or insects were found, additional measures are taken. feeding blue cabbage:

1. The lack of phosphorus is compensated by applying liquid fertilizer “Isagri”. The composition, in addition to phosphorus, includes components necessary for its absorption. Experienced gardeners also use superphosphate (100 g per 1 bucket of water) and double superphosphate (50 g per 1 bucket of water). Or dilute 1 tsp in 1 liter of water. bone meal. They also fertilize with rotted manure or chicken droppings (3 kg per 1 sq. m).
2. Soil acidity affects the absorption of phosphorus. The higher this indicator, the worse the microelement is absorbed.Cabbage grows well in loamy soil with a neutral (or close to neutral) acidity level of 6.2–7.5. Lime or dolomite flour, wood or peat ash, chalk or slaked lime will help lower the pH.
3. If the cause of blue discoloration is a lack of nitrogen, the problem is solved by adding rotted manure (3-4 kg of raw materials per 1 sq. m). A mullein solution (1:10), ammonium nitrate (20 g per 10 l) or urea (30 g per 10 l) are also used.

In case of excessive precipitation, the soil should not be allowed to become waterlogged; therefore, if possible, the beds are covered with plastic film. From the beds there are grooves for water drainage, and the soil is loosened daily to a depth of 3-5 cm. If the reason for the change in leaf color is dry soil, increase watering by adding 2-3 liters of water under each plant using the drip method.

Important! After applying the necessary fertilizers and leveling the soil moisture, the blue discoloration from the cabbage leaves will disappear no earlier than 10-14 days.

Temperature protection

Most cabbage varieties are cold-tolerant, but sudden changes in temperature cause the leaves to turn blue.

To prevent color changes and deterioration of taste, the following measures are taken:

• the beds are insulated with agrofibre or spunbond: when the temperature drops to -10°C, white agrofibre is used, which also protects against snow and hail;
• the soil is mulched with peat, humus or straw;
• wait until it gets warm - the blueness goes away on its own.

Prevention of diseases and pests

If the blue color of cabbage foliage appears due to disease or pests, save the plant using the following methods.

Blackleg

Before planting, the sprouts are inspected for signs of disease, and the affected seedlings are thrown away. The same is done with adult plants to prevent further spread.

In case of minor damage, the soil is treated with a weak solution of potassium permanganate - 1 liter for each bush. Strong spread is stopped with Fundazol or Planriz. If the disease continues to develop, the plants are uprooted and the soil is disinfected with a 1% solution of potassium permanganate or copper sulfate.

For prevention, use a solution of calcium nitrate or milk of lime (1 tbsp of lime per 10 liters of water). Blackleg often appears due to shade and lack of air, so cabbage is planted according to a certain pattern: 70 cm between plants and 80 cm between rows.

Kila

When infected, diseased bushes are removed and burned. In their place, plants are planted that are not susceptible to this disease, since the infectious agents remain in the soil for up to 7 years. For prevention, pour 3 tbsp into the planting hole. l. ash or 1 tbsp. l. calcium nitrate. The additive is poured into 1.5 liters of water. P

Increased acidity of the soil provokes the appearance of clubroot, so if this indicator is higher than normal, liming of the soil is carried out (200 g per 1 sq. m).

Cabbage fly

In case of cabbage fly invasion, the plantings are treated with “Karbofos” or “Topaz”. Helpful neighbors can repel the pest: parsley, wormwood, marigolds. Once a month, the bushes are dusted with black pepper and dry mustard (1:1).

Aphid

Aphids are destroyed with Fitoverm. For preventive purposes, dusting with ash or spraying with garlic broth (400 g of heads in the husk is boiled for 2 hours in 10 liters of water), yarrow solution (1/3 of a bucket is poured with boiling water and left for several hours) or infusion of citrus peels (1 kg per 10 liters) is used. .

How to avoid the problem of purple leaves in cabbage

To make growing cabbage less hassle, follow simple rules:

• varieties for planting are selected based on their climatic conditions in the region;
• Before planting, seeds are soaked in a weak solution of potassium permanganate;
• before transferring to open ground, seedlings are hardened by staying outside, starting from 30 minutes and ending with full daylight hours;
• the soil for cabbage should have a neutral or close to neutral pH;
• follow the rules of crop rotation: cabbage is not planted after plants with which it has common diseases (radish, radish);
• for planting, choose well-lit areas, maintaining 70 cm between plants and 80 cm between rows;
• do not over-moisten the soil and do not allow it to dry out;
• carried out on time feeding and preventive measures to combat diseases and pests.

Read also:

Early maturing cabbage hybrid Krautkaiser F1

Ultra-early ripening cabbage hybrid Nozomi f1

What are the benefits of Romanesco cabbage, what it looks like in the photo, is it difficult to grow?

Conclusion

Keeping it simple rules for caring for cabbage and using the tips from our article, even beginners will receive a rich harvest with juicy and tender white-green leaves.

Monitor the nutrition of the plants, carry out preventive treatments against pests and diseases, protect the cabbage from temperature changes, and then you will not encounter the problem of blue foliage.