How To Identify, Control & Prevent Blossom End Rot On Tomato Plants (A to Z Guide)

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Quick Answer: How To Identify Blossom End Rot And Control Them On Tomato Plants?

Blossom end rot is a physiological disorder of tomatoes caused by stress and calcium deficiencies. It develops lesions on the bottom end of the fruits. There is no cure for the affected fruits. The condition can be prevented by correcting watering irregularities, adding a layer of mulch, and applying calcium to the soil after performing a soil test.

In this guide, I will talk about the identification, control, and prevention of blossom end rot in tomatoes.

Keep reading to know more!

What Is Blossom End Rot, And How Does It Harms Tomato Plants?

Blossom end rot is a common problem of tomatoes caused due to lack of calcium and uneven watering. It is not caused by disease or pathogens. It may occur during the initial fruit set.

It affects both green and ripe tomato fruits reducing the fruit quality.

Here is a video on blossom end rot:

How To Confirm That Blossom End Rot Is Troubling Your Tomato Plants?

Look for the telltale signs in the fruit. You may observe water-soaked, depressed areas that widen into sunken, brown spots on the bottom end of the fruits. The black-bottomed tomatoes confirm the blossom end rot while the top of the tomato looks normal.

You may occasionally observe two or three lesions in the bottom as the disease progresses.

In extreme cases, black, fuzzy-like growth will appear on the affected area, causing complete rotting of the fruit.

Check out this video on identifying blossom end rot:

Natural Ways To Control Blossom End Rot On Tomato Plants

If your tomato plants produce few fruits with lesions, you may reverse the conditions by changing the watering habits and adding a layer of mulch so that other fruits are not affected.

Also, lime, antacids, and eggshells can be added only if the soil lacks calcium.

Method 1- Correct The Watering Issues

Tomato plants require consistent watering to control the blossom end rot in other fruits throughout the growing season. The vines need at least an inch of water every week.

  • Correct the watering– Remove the affected fruits and correct the watering irregularities. You may use water from the hose or sprinkler if the tomatoes do not get enough rain. Also, water in the morning so that foliage dries before evening.

Click this video for watering tomatoes:

Method 2- Add A Layer Of Mulch

Mulching around the base of the tomato plants helps to retain soil moisture, especially during hot, dry days. Also, it slows down the water loss from the soil, which in turn reduces the formation of blossom end rot.

  • Add a layer of mulch– You may add a layer of mulch, including straw, sawdust or newspaper, to retain moisture. Make sure to leave two inches of room around the stem for absorption by the roots. The new fruits will develop without any signs of rot.

Click this video on mulching tomatoes:

Physical Ways To Control Blossom End Rot On Tomato Plants

You may remove the affected fruits from the vine as it will not regrow or repair themselves.

The condition may not spread, but the damaged area may serve as an entry point for disease-causing pathogens.

Chemical Ways To Control Blossom End Rot On Tomato Plants

Blossom end rot is not caused by a fungus, bacterium, or virus. There is no chemical fungicide that will work as a control measure as it is a physiological condition.

How To Prevent Blossom End Rot In Tomato Plants?

The key to preventing blossom end rot is maintaining consistent moisture. The other measures to manage the condition include adding a layer of mulch, rectifying calcium deficiencies, and avoiding disturbing roots.

Also, avoid growing varieties that have consistent problems with blossom end rot.

Method 1- Correct Watering Issues

Water consistently and regularly to the tomato plants as inconsistent watering causes calcium deficiency and blossom end rot.

Also, these plants need an inch of water per week from rainfall or irrigation.

 Method 2- Add Mulch

Add two inches of organic mulch around the base of the tomato plants to retain moisture during dry periods.

You may use a straw, grass clippings, leaves, or shredded bark as much. Also, it helps in reducing weeds.

Method 3- Correct Calcium Deficiencies

Perform a soil test and check calcium levels. Add an organic source of calcium, including lime, bonemeal, or crushed eggshells if the soil is lacking in calcium.

Avoid using fertilizers with too much nitrogen, magnesium, and potassium.

Check this video for correcting calcium deficiencies:

Method 4- Avoid Disturbing Roots

Do not disturb the root zone of tomato plants as it helps in absorbing the calcium. Avoid digging and hoeing in the plant’s root zone.

Pull weeds and don’t work close to the ground, and maintain soil pH close to 6.5.

Check this video for preventing blossom end rot:

What Causes Blossom End Rot Attacks In Tomato Plants?

Blossom end rot is caused by a deficiency of calcium combined with stress. It can be due to low calcium levels in the soil or impaired uptake of calcium.

It can also be triggered by drought stress, irregularities in soil moisture, and damage to plant roots affecting calcium uptake.

Also, plants may develop blossom end rot if they grow in acidic soil, are over-irrigated, or have high relative humidity.

Frequently Asked Questions

What are the causes of calcium deficiency in plants?

The different causes of calcium deficiency include excessive nitrogen-heavy fertilizer, fluctuations in soil pH, high salt levels in the soil, and damage to the plants’ roots. It may also be due to irregularities in watering the plants.

Do blossom end rot spread to other plants?       

No blossom end rot is not spreadable or contagious. It doesn’t spread from one plant to another. It is a physiological condition caused due to calcium deficiencies. Eventually, other plants near may suffer as they share similar growing conditions.

Can you eat tomatoes with blossom end rot?

Yes, you may eat the tomatoes with blossom end rot. Cut away the damaged blackened part and eat the undamaged parts of the fruits. You may also can these fruits. Discard the fruits that have pests or larvae inside them.

Can you use a calcium-based spray to control blossom end rot?

Few gardeners advised calcium-based sprays for leaves to avoid blossom end rot. But, it may not work as the calcium has to be adsorbed from the roots and can not be absorbed from leaves.

Will the seeds saved from blossom end rot-affected tomatoes produce tomatoes with that affliction?

No, the seed saved from tomato fruit affected with blossom end rot may not produce tomatoes with lesions. It may be because the condition is produced as a result of the conditions experienced during the formation and ripening of the fruit.


I hope this guide has given you many tips and considerations in controlling and preventing blossom end rot in tomatoes.

Please let me know if you have tried any methods to control the physiological condition.

Do share the guide with your friends and family!