Yellowing of leaves on plants isn’t new. Plants try to shed old leaves that are no more effectively taking part in food production.
So, to some extent it’s normal and there is nothing you can do to stop it.
However, there are several other factors that cause stress and the plant leaves turn yellow.
In this write-up you’ll learn why cabbage leaves are turning yellow and most importantly are these leaves edible?
As mentioned, there are several factors that lead to discoloration of leaves. Environmental stress, overwatering, underwatering, lack of fertilizers, club root disease, cabbage black rot or pests can be reason behind yellowing of leaves.
It is very important to determine the mere cause, because some factors can’t be just ignored. Is it a disease or your careless gardening that resulted in yellow leaves? This must be confirmed first. Accordingly, you’ll be guided with possible ways to save the plant.
Why Cabbage Leaves Turning Yellow?
You can grow cabbage at different seasons to get uninterrupted yield. Early, mid-season and late seasonal growing of cabbage is recommended by most gardeners.
As they say, along with bountiful of yield you must expect handful of problems. Cabbage leaves turning to yellow is one such disorder.
As mentioned before, various factors influence yellowing of leaves in plants. Initially, you must know the cause and accordingly you can fix them.
Out of curiosity, most new gardeners water their vegetable plants more often, resulting in excess water clogging in the plant pot.
Overwatering cabbage plant will block nutrients in the soil to enter leaves through roots. This is because the root system starts rotting and due to insufficient nutrients, leaves starts wilting and turning yellow.
Potting soil plays vital role in growing efficient plant. If the garden soil in the container isn’t well-drained it halts easy flow of water resulting in overwatered plant.
How to fix:
If the growing medium you choose is well-drained and fertile, then probably you’re watering your plant more frequently.
Stop watering your plant till the soil turns dry. You can check for dryness by inserting your indexing finger in the soil. If needed relocate the pot, so that the plant gets enough sunlight and extra moisture easily evaporates to atmosphere.
Also Read: How Often Should I Water Basil Plants?
The moisture you provided to the potting soil may not be sufficient in summer. You must regulate watering frequency according to the changing weather conditions.
Not watering your plant with required amount results in shriveled and drooping leaves. Slowly, leaves starts wilting and turns yellow.
How to Fix:
Water your plant generously till you see the extra water is out of drainage hole in the container.
Don’t allow the soil to dry 100 percent. Water generously, when you find the soil is 70 percent dry.
Check this out: Cauliflower Leaves Turning Yellow
#3 Natural Aging Process
To determine if yellowing of your plant leaves is natural or due to any disease, then check out these three things.
- Yellowing of lower leaves. If you see only lower leaves are turning yellow, then you shouldn’t worry.
- Check out if the yellowing is at slow rate. Natural aging and yellowing will gradually change the leaf color.
- You don’t see any abnormalities like drooping of leaves or drying of tip of leaves. (Source)
Anyhow, if the plant is facing nutritional deficiency, then yellowing starts from lower leaves and spread to upper leaves.
If you’re sure that yellowing of your cabbage plant leaves is normal, then you don’t have to do anything.
Also Read: Growing Cabbage from Scraps
#4 Environmental Stress
Sunlight, temperature and humidity will impact the growth of your cabbage plant.
Before growing your cabbage plant, you must be aware of the growing conditions of it.
Extreme exposure to harsh sunlight can result in drying of leaves. Similarly, low light can lead to yellowing of leaves.
It is essential that you provide adequate amount of sunlight, water and nutrients for this plant.
- Sunlight: Full direct sunlight for about 6 to 8 hours.
- Temperature: 60 F to 70 F is optimal. It can tolerate winter, but frost can damage the head of cabbage.
- While germinating cabbage seeds, the soil temperature can be as low as 40F. (Source)
- Soil: Well-drained fertile soil.
#5 Fertilizers Deficiency
Low levels of nitrogen (nutrients) will result in pale-yellow leaves.
NPK is very essential for plant growth. These nutrients are responsible for green foliage, food production, developing root system, blooming and to increase yield.
Low levels of fertilizers results in yellowing of leaves and stunted growth.
How to fix:
You must add nitrogen rich liquid fertilizer to ensure fast recovery.
#6 Club Root Disease
If you’re plant gets infected by this diseases then its leaves will turn yellow and its growth will be stunted.
Roots of this disease infected plant will be swollen and the adult plant will fail to produce yield.
If you notice yellow leaves and stunted growth on your cabbage plant, then chances are the fungus already attacked root system.
This disease is caused due to fungus that may enter through improperly produced compost or by passing from infected transplants.
How to fix:
Gardening experts say, prevention is the best way to deal with club root disease.
Before transplanting, ensure that they are free from diseases. You can check the roots, if they are swollen and clubbed, you shouldn’t grow them in your garden.
While borrowing soil from other garden, check out the soil has no history of club root disease.
In case you find club root in your garden soil, stay away from planting brassica family (cabbage family) for 7 years.
Read more on this disease here.
#7 Pests and Diseases
You should watch your growing cabbage plant for pests and possible fungal infection.
Like mentioned above, fungal infection can attack roots and results in yellow leaves.
Similar, fusarium is a fungus that blocks vascular system of the plant resulting in wilting and yellow leaves.
Powdery mildew forms white fungus plague on back of the leaves and yellow patches are formed on upper side of cabbage leaves.
Due to pests and disease infestation, your cabbage leaves may turn yellow and the plant growth will be slowed.
Important Tip: Best way to avoid these diseases is to choose hybrid cabbage varieties that are immune to cruciferous diseases.
Cabbage Black Rot
This disease is common is cabbage family and it attacks stem and vascular system of the plant. When you cut the plant you’ll find black ring near the soil surface.
Yellow V shaped lesion is a sign of cabbage black rot.
This bacterial infestation can spread to other plant through transplantation and infected soil.
Wet conditions with temperature ranging from 80-86F are favorable conditions for this bacterial infestation.
Check out this site to read more about this disease.
Can Cabbage Leaves Be Stopped from Turning Yellow?
If the cause of yellowing is due to overwatering, underwatering, lack of nitrogen or low sunlight, then you can reverse yellowing.
But, if the yellowing of leaves is due to club root diseases, then you should let the plant go. You must remove it.
In this case, just trimming yellow leaves won’t help, because club root diseases attack root system.
Unfortunately, there is no fungicide that can effectively fight club root disease.
While choosing cabbage variety, ensure that you prefer the hybrid varieties that are resistant to diseases.
Also, the soil and tools you use must be free from infestation.
Watch out your plant regularly, to remove any pests or fungal disease.
Apart from this, basic growing tips like regular watering, well-drained fertile soil and adequate amount of sunlight must be provided to get good harvest.
I hope, this article helped you to know causes of cabbage plant leaves turning yellow.