Why Are My Brussels Sprouts Plant Leaves Turning Yellow

 The thought of having a great season without any problems from your plants has an amazing feeling. However, as you know, it’s less likely to happen. No matter how careful you are with plants, there can be one or two problems; if you are lucky, you can solve them instantly. 

The common problem is Brussels sprouts plant leaves turning yellow. You should be worried when the leaves start to turn yellow on a green plant. 

So, if you ask yourself, “why are my brussels sprouts plant turning yellow?“ The simple answer is that the yellowing is caused by overwatering, under-watering, too much exposure to direct sunlight, lack of nutrients, poor air circulation, and attack by pests and diseases. 

Some problems that affect the brussels sprout plant are caused by what we do, and others are just natural. For instance, you can control overwatering, but since most people don’t know how much water a plant needs, they tend to give it more than it needs. It results in the plant leaves turning yellow. 

Below, we will see the different things that happen to the plant to make Brussels sprout leaves turn yellow. 

Why are Brussels Sprouts Plant leaves turning yellow?

Brussels sprouts are plants from the cabbage family. Like cool weather, they need the sun for growth. When planting them, ensure you start planting so you can harvest during the cold season. 

Such instances can make your brussels sprout leaves turn yellow. Here are the other reasons that make the plant turn yellow. 

Too much sunlight

All plants, even indoor plants, require a good amount of sunshine during the day. But that can go beyond the required amount, especially for outdoor plants. During summer, you get full days of sunlight.

When the plant gets direct sunlight for more than 8 hours a day, it can scorch the leaves. Leaves turn yellow when they are burnt by the sun. Some plants adapt to the condition, and others can’t. 

You can provide shade for outdoor plants and increase the water you give them. Give it at least 6 to 8 hours a day. Water can cool the plant and ensure brussels sprout leaves don’t turn yellow.   


Overwatering is a common practice among farmers. Most of us can’t accept it, but we have done it to our plants. The lack of a watering schedule usually causes it.

When you give the plant more water, it stays stuck on top, leaving the soil soggy. Soggy soil causes root stress, which can lead to root rot. When the roots start to rot, the leaves start to turn yellow. Eventually, the plant will wilt and die.  

You can solve this problem if you find it early. First, stop watering and see if the leaves return to normal. Secondly, check the roots if they are healthy or rotten. Remove rotten roots and leave healthy ones. Replant the plant in fresh soil, and give the soil a small amount of water. Keep checking the plant until it returns to normal. 

The best way to water your plant is to leave intervals between the watering for the soil to dry.  Keep the soil moist but not soggy. 

Under watering

People often argue that it’s better to go underwater than to overwater. It might be true, but it can cause your plant problems. 

Under-watering causes the plant to strain in search of water. The roots start to grow downside, and the leaves turn yellow to adapt to conditions. Eventually, it will lack water and dry out. 

You can notice what’s causing the problem if your soil is dry. Start giving the plant water slowly until it recovers. Always ensure the soil is moist.

Poor air circulation

Poor air circulation can be caused by poor soil quality. Proper air circulation ensures the plant roots breathe fresh air. 

When we talk about poor soil quality, it means the soil doesn’t have space. Soil that doesn’t have proper spaces can’t drain water properly, and it can’t allow air through it. On the other hand, soil with poor drainage leaves the water stagnant at the top. When it accumulates over time, it can cause the roots to rot. 

If you have this problem, you can change the type of soil you are using. You can purchase potting soil for those with containers and report the plant. 

Spacing between plants

Brussels sprout leaves turning yellow can also result from the poor spacing between plants. When the plants are close together, they tend to compete for food, which can cause one of them to lack nutrients. 

Give the plants enough space from the beginning. It ensures that they have their food around them.

Poor fertilizing

Poor fertilizing can result from placing more, little, or no fertilizer in the soil mixture. 

When the soil has little to no fertilizer, the plant lacks nutrients. Brussels sprout leaves turn yellow when they lack nutrients. You can add borax to the soil to solve the problem—eventually, the plant wilts.

On the other hand, too much fertilizer can burn the plant. You can notice this, some parts of the leaf have either brown or yellow spots. 

Follow instructions provided by the plant tag or the fertilizer vendor on the amount of fertilizer per land. If you are using potting, the tag has instructions on how much fertilizer you can add. 

Attack by diseases

Diseases are another problem that can lead to brussels sprout plant leaves turning yellow. Some diseases that attack the plant include Bacterial leaf spots, black rot, cabbage worms, club root, Downey mildew, fusarium wilt, powdery mildew, white mold, white rust, and ring spot. 

The diseases affect the plant in various parts, but most affect the leaves. You can spot patches on leaves when these diseases affect your plant. 

The best way to deal with diseases is to spray herbicides to remove them. Spray water on the soil around the plant. When you use overhead spray, the water lands on the leaves and remains stagnant, bringing bacteria. Avoid it.

If the disease persists, cut off the plant to avoid spreading to other plants, and then skip planting brussels sprouts the next year so that the diseases die off. 


Bolting happens when brussels sprout starts to grow flowers for seeds. When the flowers start to grow, the plant has reached its end of life. So, the sprouts will no longer grow from this plant. 

Sometimes, bolting starts too soon before the plant has reached its maximum potential. Usually, it happens when it senses cold temperatures. The plant will know the growing season is over as cold temperatures persist and start producing flowers. 

The yellow leaves indicate the plant is dead for the season. If the temperature drops below 50 degrees Fahrenheit, it will bolt. 

Ensure your plant has optimum temperatures above 5 degrees Fahrenheit to grow to maturity. 


Brussels sprout plant leaves turning yellow is a problem if you don’t notice it in the early stages. Once you notice it, try to find the cause and solve the problem as stated above. If you don’t find the cause of the problem, you might not solve it correctly. 

Now that you know what makes your brussels sprout leaves turn yellow, ensure that you prevent it before it happens. We make some problems, and we can do prevention. 

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