Why My Broccoli Leaves Turning Yellow?

Growing your own healthy and delicious vegetables at home is becoming an increasingly popular activity among people all over the world. With the world around us being ridden with pollution, even the food we eat brings us the threat of consuming harmful chemicals like pesticides and fertilizers that are used to increase the yield.

Broccoli is a particular favorite among home gardeners around the world. Even though this vegetable bears the risk of gardening problems like broccoli leaves turning yellow, it is nothing short of a star when it comes to nutrition content.

Packed with health benefits, having broccoli in your vegetable garden is a must if you are planning to go on a healthy diet.

The broccolis found in supermarkets and grocery stores might have been your source of nutrition till date, but once you taste a freshly harvested organically grown broccoli, you will be able to tell the difference. Roast them, bake them, use them in pasta, or prepare delicious salads and soups- broccolis bring you millions of healthy food options that are equally delicious.

Also Read: How to Propagate Broccoli?

Mostly broccolis are hardy vegetables that would not keep you on your toes. However, just like every other plant, they have certain requirements, which when left unfulfilled, the plants would protest.

One of the most common problems with these plants, as reported by gardeners all across the world, is that of yellowing leaves. This can be a very tricky situation, as it leaves the gardeners wondering where they went wrong. A lot of reasons can cause this unfortunate event and it often becomes difficult to resolve the crisis.

Although this problem can mostly be resolved with a little watchfulness and quick response on the part of the gardener, when ignored for a long time, it can even cause the death of your plants and claim a significant portion of your harvest. 

If you have been facing this problem and are clueless about what to do, do not worry anymore. You are at the right place. In this article, we have discussed the causes of the yellowing leaves of broccoli plants in detail along with the most effective solutions. So read on and find the end to this frustrating problem once and for all.

Introduction: Know Your Plants

Packed with health benefits, broccoli has been assigned the title of the ‘Crown Jewel of nutrition’. This cool-season, sun-loving crop is a cruciferous vegetable belonging to the family of cabbage and cauliflower.  

Broccoli is a floral vegetable grown for its edible head. A healthy broccoli has an exotic appearance with a dark green color from the head and the stalks to the leaves. Broccoli is a heavy eater, requiring rich, fertile, and sandy soil.

A rich source of numerous vitamins and minerals, a few servings of this vegetable alone can make sure that your body’s nutritional needs are met. Full of essential nutrients, broccoli is a great source of Vitamin A, fiber, iron, folic acid, and phosphorus.

It is advisable to grow broccoli in early spring or late summer, always avoiding the mid-summer heat. Temperatures between 65°F to 70°F are ideal for the growth of this vegetable. These plants are lovers of direct sunlight and would therefore require at least 6 to 8 hours of sun every day.

Also Read: How to Grow Corn Microgreens?

Broccoli plants also require sufficient water for proper growth. Make sure that you provide your plants with enough water to keep their beds moist. However, waterlogging is harmful to your plants. Well-drained soil is, therefore, a must.

Why Are Broccoli Leaves Turning Yellow?

As you already know, broccoli, the healthiest vegetable is also very easy to grow. It just needs a little bit of care and patience. A great thing about growing broccoli is that all the problems that the plant gets into are visible to the naked eye. And if spotted early most of the problems are very easy to treat. Such is the problem of broccoli plant leaves turning yellow.

During the process of growing broccoli, you may notice sometimes that the leaves or the tips of the flowers are turning yellow. In most cases, this is not a very alarming situation. However, you must inspect the problem thoroughly to determine the actual problem behind the yellowish hue. We are going to discuss such problems one by one here.


This is one of the most common reasons behind broccoli plants turning yellow. It mostly happens to the flower. The plant leaves don’t get affected by over maturation unless the season for the plant ends. The green head of the broccoli plants is actually made up of several small flowers clumped together.

They are called florets. If the broccoli heads are not harvested when they have grown to their maximum size, they will start to mature. In other words, the flowers will start to bloom. They will swell in size and turn into bright yellow buds.

This makes the broccoli taste bitter and the crunchiness of the green broccoli also goes away. If left unchecked, the broccoli flowers will soon burst to spread the seeds that they contain inside them. So it is always better to harvest the broccoli heads just as they grow to their maximum size, while they still remain green.

Deficiency of Nitrogen:

As you already know that broccoli plants are very high in nutrients. To maintain the green color and to store all the minerals and antioxidants that we farm them for, broccoli plants need a lot of food. It is very easy for a new gardener to underfeed a broccoli plant. This heavy feeder plant needs a lot of nitrogen from seeding two harvestings.

If the nitrogen needs are not being met the plant will start to turn yellow. At first, you will notice that the bottom leaves are turning yellow. The yellowing then gradually spreads to the rest of the plants, moving up towards the head. If the problem is not taken care of at an early stage, the whole plant turns yellow and impoverished. It then wilts and dies.

Fungal infection:

Fungi are very sneaky parasites. Fusarium oxysporum is one of the worst fungi that can harm your plant. This sneaky fungi attacks from the soil. During plant transplantation or soil changing, the roots of the tiny plants can easily get torn, injured, or cut.

This provides the perfect opportunity for the fungi to attack your tiny broccoli seedling. These fungi enter the plant through the roots then grow into its stem. At this stage, you cannot tell any difference.

Soon after, one side of the stem of the plant gets stunted and the whole plant starts to curve in one direction. Along with this, the leaves also start to turn yellow. The fungi suck out all the nutrients from the plant and the plant gradually dies.

Black Rot:

Broccoli thrives in dry and cold weather. Too much heat or too much moisture can cause black rot in broccoli plants. When black rot appears it can be identified by the v-shaped yellow lesion forming at the base of the leaves. This is why every now and then you should inspect the leaves around the broccoli head.

Once the lesion appears it will infect the veins. Eventually, the veins start to turn black and the leaves start to turn brown. If left unattended for a long time, the black rot will start to release a yellowish fluid. Gradually the whole plant will wilt, dry out, and die.

Club Root:

This problem is usually caused by a fungal infection. While transferring your plant from one soil to another you may notice clubroot. If affected by clubroot the roots usually get swollen. This is a sign of fungal infection. Due to this fungus, the leaves dry up during the day when it is hot.

But they again rejuvenate when it is night. This infection can happen if your soil is acidic and the pH level is below normal. You should uproot the affected plants at once. Composting the affected plants will further transfer the fungi to another plant.

What To Do To Save Your Broccolis?

Now that you know all about the problem of yellowing broccoli leaves, hopefully, you are no longer wondering, “why are my broccoli leaves turning yellow”. However, mere knowledge of the causes won’t solve your problems. To tackle the situation effectively, take the following steps.

  1. In case the cause of your yellowing broccoli leaves is over-maturation of the plants, harvest the vegetables immediately. Keep in mind that the ideal time to harvest the main shoot of broccoli is when it stops expanding and the flower buds are still green. If you leave the vegetables in the garden long after this point, along with yellowing, their taste too, shall deteriorate.
  2. If the problem is caused by a nitrogen deficiency, add a nitrogen-based fertilizer to the soil. Broccoli is a heavy eater. This means that these plants require a lot of nourishment from the soil to produce healthy vegetables. Make sure that the fertilizer is lower in phosphorus content. You can always go for the easily available, factory-made fertilizers that would provide your plants with an adequate amount of nitrogen. However, it is always advisable to use organic fertilizers to maintain the organic quality of your garden. Using naturally made compost might be the best option available. You can also use blood meal. To increase the nitrogen content of your soil, try crop rotation with legumes.
  3. Transferring the plants to a cooler environment can also help your plants have a healthy growth.
  4. In the case of fusarium infestation, there is not much you can do after this fungus has already invaded your garden. It is therefore vitally important to notice the signs of the infestation while there is still time. If you are too late to recognize the signs, the fungus can destroy your garden in no time at all. The only successful control measure that can make any difference once the fungus has already developed would be to prevent it from spreading out to other plants. For this purpose, try to identify the infected plants and isolate them. If required, uproot these to save the rest of the garden.
  5. Try crop rotation to prevent fungus, pests, and other diseases from taking root in the soil. This would make sure that your next season broccoli plants remain safe from the yellowing problem. Have your soil tested before planting the crops to check for the right pH levels and nutritional content. Only plant your broccoli plants after ascertaining that your soil can meet all the requirements of the plant.

Broccoli is a comparatively easier plant to grow in home gardens and comes with a host of benefits. However, certain gardening problems are inevitable, no matter how green a thumb you have.

As a gardener, being careful regarding the needs of your plants and watching over their growth can go a long way in combating any gardening problem. Therefore, in order to make sure that you can harvest a batch of perfect broccolis after the growing season, provide your plants with proper care.

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