Author's rating
Author of the article
Yakov Pavlovich
Professor, Head of the Department of Vegetable Growing
Articles written
153
If yellow leaves are observed on the bottom of the cabbage at the end of the season, the plant is ready for harvest. But sometimes this situation occurs at the height of the season. Here is the time to wonder why the leaves of still young cabbage turn yellow. There may be several reasons for this phenomenon. The main thing is to find out this as early as possible and put effort into correcting the situation.
Improper watering
Lack or excess moisture may be one of the reasons.
If you water too much, the soil becomes compacted and a dense crust may form on its surface. As a result, the root system does not receive enough oxygen, the roots of the cabbage seedlings begin to rot, the leaves turn yellow and die.
In the case of poor watering, the seedling does not receive the amount of nutrients it needs from the soil, plant development slows down, and the leaves begin to turn yellow. Watering should be sufficient, and in case of overflow, be sure to carefully loosen the soil.
Why do cabbage seedlings turn red?
We have already mentioned that with a lack of nitrogen, cabbage leaves begin to turn yellow. But this is at the beginning of the process. If the situation is neglected, the lower leaves will continue to change color and turn from yellow to red. The solution is the same - timely feeding of seedlings.
A reddish-purple tint on the undersides of leaves may also indicate a lack of phosphorus in the soil. This can be especially pronounced in cold, cloudy weather, when the roots do not have time to fully absorb useful elements. Rains can even “wash away” phosphorus to depth, depriving small roots of seedlings of the opportunity to reach it. Therefore, cabbage should be fed, for example, with superphosphate. Since the acidity of the soil has a great influence on the absorption of phosphorus by plants, it should be limed in a timely manner.
- Cabbage protection and feeding system: from seeds to storage
Is your cabbage regularly attacked by bacteria and insects? We'll tell you how to protect your crops and save your harvest.
Temperature changes
One of the traditional reasons for the death of white cabbage seedlings is the incorrect temperature conditions during its cultivation.
To obtain strong and healthy seedlings, it is necessary to provide optimal conditions for their development. Cabbage loves the cold and does not need greenhouse conditions.
The most suitable air temperature for the full growth and development of cabbage seedlings is from 8 to 10 degrees Celsius.
In more comfortable conditions, seedlings present an unpleasant surprise to the caring gardener. They stretch out, the root system develops poorly, new leaves turn yellow, and the plant dies.
Root damage
Can happen for various reasons. Cabbage seedlings can suffer mechanical damage to the root system when picking; it must be done very carefully.
Loosening the soil, if necessary, should also be done very carefully. The roots of young seedlings can also be damaged by insects, so care should be taken to protect them.
In rare cases, the cause of death of the root system of cabbage seedlings can be sea sand, or more precisely, the salt that is part of it. It is poisonous to the root system. In this case, immediate replanting of the plants into another soil with thorough rinsing of the root system with water is required.
Holes in cabbage seedlings - what could it be?
There are different pests of cabbage seedlings, but most of them happily gnaw on the young pulp - so their presence is easy to detect by the holes on the leaves of the seedlings.
Who eats cabbage seedlings? Tiny black cruciferous flea beetles and brightly colored cruciferous bugs, caterpillars of cabbage moths, cabbage cutworms and cabbage white butterflies, cabbage leaf beetles (both the beetle itself and its larvae). As you can see, there are many options, and all these insects need to be dealt with urgently before they leave you without a harvest.
- All garden pests in tables with descriptions, photos and control measures
We have compiled a “dossier” for you on each pest - save this collection!
Pests
When growing cabbage seedlings at home, the list of pests that can damage plants is small.
First of all, you should be wary of spider mites. This is a very small pest, which is why it is especially dangerous.
It is very difficult to notice it with the naked eye until the results of its vital activity appear. These are small cobwebs, black spots and sticky secretions; they usually predominate on the underside of the leaf.
The leaf quickly turns yellow and the plant may die. Measures to combat this pest do not have much effect.
In order to avoid plants being damaged by spider mites, it is necessary to thoroughly wash the sowing containers and the place where they will be located after sowing cabbage seeds for seedlings. A weak solution of vinegar will help.
Cabbage seedlings suffer greatly from aphids. Not everyone knows that in this case it is necessary to fight not only aphids, but also ants. Baking soda will help, sprinkle it dry on the ground.
After planting seedlings in open ground, it is a good idea to sprinkle them with wood ash, tobacco dust, or water them with a weak solution of ammonia to protect them from various pests.
Downy mildew
Downy mildew can be expected at any stage of crop development, but is more often noticed on seedlings. On the bottom of the cabbage you can find a gray coating in the form of single or merging dots. On the other hand, yellowing is observed on the leaves, which turn white over time. If the defeat is severe, then the culture gradually dies off.
Downy mildew also affects the seeds, on which the leaves, stems, pods and pedicels are affected. Over time, everything gradually becomes covered with plaque, the seeds in the pods become dull.
There are several ways to protect culture from this nuisance.
- Collecting seeds from healthy plants with mandatory further disinfection before planting.
- Maintaining the required sowing density.
- Timely, systematic ventilation of the greenhouse (if the crop is grown in a greenhouse).
- Cleaning up plant residues after harvesting.
- Organization of competent crop rotation.
- Growing resistant types of crops.
Diseases
At the stage of growing cabbage seedlings, the most common diseases are fusarium and blackleg.
It is with fusarium that the leaves of cabbage seedlings turn yellow, wither and die.
If fusarium is the cause of this phenomenon, it is better to remove the plants from the box or from the seedling bed to avoid further spread of this fungal infection.
Blackleg leads to the death of the plant. The stem darkens and becomes thinner. The cause may be too thick seedlings, excessive watering and watering with too cold water, sudden temperature changes, acidified soil, poor ventilation, excess nitrogen in the soil, poor lighting.
Black rot can also affect cabbage seedlings. In this case, the leaf turns yellow from below, the plant turns black from the inside, and black dots can be seen on the leaves. The reason may be infected seeds; spores can also be spread by pests. Sometimes the disease develops due to a sharp change in temperature and bad weather conditions (prolonged rains at above-zero air temperatures). Plants affected by blackleg are destroyed.
Separately, we should talk about the keel. This is a very dangerous cabbage disease. Its signs are swellings on the roots that look like nodules. You can notice them when picking cabbage seedlings or planting them in the ground. You just need to carefully examine the root system. Clubroot cannot be treated; plants should be destroyed at the slightest suspicion of this disease.
Reference! Infection occurs through the soil; if a disease is detected, it must be treated with a fungicide.
Blackleg
Signs
The first sign of blackleg is thinning of the stem in the root zone with its simultaneous blackening. At the same time, the lower leaves become thinner, turn yellow and become covered with dark spots.
Reasons for the development of blackleg:
- use of contaminated seed;
- waterlogging of the soil;
- temperature difference;
- increased soil pH level;
- dense planting.
Prevention
Preventive measures are aimed at both working with seed and soil.
- Treatment of seeds with Fitosporin at the rate of 2 drops per 200 ml of water or Baktofit.
- Calcination of the soil in the oven at a temperature of 100 degrees for 30 minutes.
- Adding wood ash to the soil to lower the pH level.
- Treating the soil with a solution of manganese or copper sulfate.
Treatment
If a black leg is found on cabbage seedlings, the affected bushes are removed, healthy ones are transplanted into new containers with mandatory watering with a manganese solution. Seedlings are sprayed with Fitosporin-M and the leaves are treated with Pervikur Energy.
How to deal with the reasons?
To obtain healthy and strong cabbage seedlings, it is important to follow all the rules of agricultural technology. Immediately after sowing, plants need to create an optimal regime: provide the desired air temperature, ventilation, good lighting and sufficient watering.
For sowing, you need to choose only high-quality seeds. Good planting material is one of the conditions for obtaining healthy seedlings.
The soil for sowing is also important. It should be quite nutritious, moisture- and breathable. Before sowing, the soil should be sifted, treated against diseases and pests, fertilized a little and sand and ash added to it.
Ready-made soil purchased in a store has already been processed and does not require additional fertilizing . This is important to consider; an excess of nutrients can also harm plants.
It is imperative to observe the timing of sowing seedlings. In open ground, it is better to plant plants with three to four true leaves. Cabbage seedlings develop quickly enough, so there is no need to sow them too early. Otherwise, the plants will outgrow and take longer to take root after planting in open ground.
Compliance with all conditions allows you to grow healthy white cabbage seedlings and an excellent harvest.
Reasons for yellowing of leaves in seedlings in a greenhouse
There may be several reasons.
One of the main ones is too high an air temperature during the daytime. If it is not possible to move the plants to the ridges, then you must make every effort to ventilate the greenhouse.
It is important to control watering of plants. In a greenhouse, when watering with a hose, an excess of moisture in the soil is possible if the air humidity is sufficiently high.
When growing seedlings directly in the soil, yellowing of the leaves can be caused by pests, diseases, and a lack of nutrients in the soil.
What causes yellowing of leaves in open ground?
To successfully grow cabbage seedlings in open ground, you need to take care of preparing the beds in the fall. Weed, dig and loosen the soil, apply the required amount of fertilizer, treat the soil against pests and diseases.
If the bed is intended for seedlings of early varieties of cabbage, then it is a good idea to stick arcs in the fall ; they will be needed to shelter the plant from the cold.
When sowing seeds directly into the ground, it is important to take care of timely picking of seedlings. If you do not plan to pick seedlings, then you need to sow less often. Thickening of crops leads to poor ventilation of plants and the appearance of fungal diseases that cause yellowing of seedlings.
When growing cabbage seedlings in open ground, it is important to provide them with proper care. It is necessary to organize proper watering taking into account the growing conditions of the plants. Excessive watering leads to acidification of the soil due to excess moisture. The root system does not have enough oxygen, this can lead not only to the yellowing of white cabbage seedlings, but also to its death.
Lack of moisture is also harmful to seedlings. Watering should be done in the morning or evening with not too cold water, taking into account soil moisture. On a sunny day, watering is necessary; on a cloudy day, it may not be necessary.
It is better to stock up water for irrigation in advance so as not to water small plants with too cold water. This can cause root diseases and rot.
On a sunny day, plants must be opened if they were covered with plastic film at night. If the air temperature outside is low, then you need to take care of ventilating the beds with seedlings. It is necessary to lift the film from the ends of the beds. Otherwise, it will be too hot under it, and the seedlings will turn yellow from high air temperatures and humidity.
On sunny days, you can shade the seedlings a little to protect the small leaves from sunburn.
After picking, the leaves of the seedlings may also turn yellow . The cause may be damage to the root system during transplantation. Yellowed leaves should be carefully removed and the plants should be watered thoroughly.
What causes cabbage seedlings to turn blue?
But sometimes cabbage seedlings acquire very unusual colors - for example, they turn blue-violet. What would that mean?
Most often, this is a “continuation” of the above-described situation with a lack of nitrogen - if you do not take measures to introduce the necessary fertilizing, the cabbage leaves will first turn pale, and then the lower ones will turn red and even turn blue. Most often, such “symptoms” of nitrogen starvation can be noticed in early cabbage in the spring or, for example, in cold rainy weather, when due to the weak activity of microorganisms, nitrogen from the soil simply does not reach the plants. What to do is described above.
Sometimes the leaves of cabbage affected by Phoma (dry rot) acquire a pinkish or bluish tint, although the gray tint of the affected tissue is more typical. As the disease progresses, plant tissues are destroyed and dry rot forms. As with blackleg, it is almost impossible to cure diseased plants. Therefore, they must be immediately removed along with the soil in which they grew. Pre-sowing seed disinfection will help prevent the development of the disease.
The purple color of shredded cabbage leaves may also indicate a lack of phosphorus in the soil. In this case, the “wrong” shade will most likely appear on the underside of the leaf, and will also be accompanied by a general delay in the growth of the vegetable. How to save a plant - see above.
If the leaves of cabbage seedlings darken and turn blue, but first the stems (legs), then most likely the matter is due to temperature stress. For example, this can happen in a film greenhouse, where the air and the upper centimeters of the soil under the shelter have already warmed up slightly, but in the depths the soil is still cold, and access to nutrients is difficult. As a result, the development of young plants is inhibited, and their legs begin to turn blue, eventually spreading the shade to the petioles and bases of the leaves. As the soil warms up and warms up, this problem will resolve itself, plant growth will resume and the blue discoloration will disappear. However, if the situation drags on, the plants may weaken and get sick.
You should not immediately try to correct this situation. Check to see if your cabbage belongs to varieties in which dark seedling stems are the norm (for example, red cabbage).
The general “bluish” appearance of the leaves of cabbage seedlings, coupled with the lethargy of the plant, may also indicate the activity of the cabbage fly, or rather its worm-like larvae. Agricultural technology in the form of deep autumn plowing, careful leveling of piles of soil, proper crop rotation, moderate fertilizing with fertilizers, and weed removal help get rid of the pest. If the plants are already infected, insecticides will help you (karbofos, Topaz, Zemlin).
Prevention measures
You can take care in advance to avoid yellowing of cabbage seedlings.
It is necessary to prepare and process planting containers . If they have already been used last season, they must be thoroughly washed with hot water and laundry soap and dried.
The soil for seedlings should be a loose nutrient mixture. If soil from the garden is used to fill seedling containers, it is recommended to mix it with ash and sand and calcinate it for disinfection.
Quality and healthy seeds are important . It is better to choose planting material from trusted manufacturers.
To obtain strong and healthy seedlings, it is necessary to provide the plants with optimal conditions for growth and development and high-quality care.
Useful video
Check out this interesting video about drying leaves of cabbage seedlings:
The main reason for failures when growing cabbage seedlings at home and in greenhouses lies in too high an air temperature. Most often, because of this, cabbage seedlings turn yellow.
If all agricultural technology conditions are met, it will not be difficult for a gardener to grow his own excellent white cabbage seedlings.
Previous White cabbage Cabbage seedlings have stretched out: what to do about the reasons for improper care? Next
White cabbageIf your cabbage seedlings are not growing well, find out what to do and what to feed
Cabbage seedlings turn yellow - why does this happen?
If cabbage seedlings turn yellow en masse, you may be guilty of the above-described fusarium, chlorosis or downy mildew (their early stages).
Also, cabbage leaves usually turn sharply yellow from the top due to potassium deficiency. Subsequently, the edges of the leaf blades become brown and they die, the plant weakens. In this case, timely application of potassium fertilizer (potassium sulfate, etc.) to the soil should help.
A lack of nitrogen in the early stages is also characterized by slower growth, shredding and a distinct “blanching” of the leaves of the seedlings, turning yellow below. In this case, you can help cabbage with easily soluble nitrogen fertilizers (ammonium nitrate, urea, etc.).
- Nitrogen, phosphorus, potassium - signs of deficiency and excess in plants
What do excess or deficiency of nitrogen, phosphorus and potassium lead to? Find out in our infographic!
