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Blossom end rot can be a hugely frustrating problem for gardeners to deal with. This is one of those problems that causes extensive damage by the time you spot it, so prevention is undoubtedly better than cure in this case.

Whether you’re battling an existing blossom-end rot problem or trying to prevent a new outbreak, we’ve got some fantastic tips to keep this debilitating issue at bay.

blossom end rot tomato disease
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What is blossom end rot?

Blossom end rot is a physiological disorder that affects fruiting vegetable crops, particularly tomatoes, peppers, eggplants, and squash.

It appears as a dark, sunken lesion at the blossom end (opposite the stem) of the fruit. These lesions are small to start with but can develop quickly and render the crop inedible.

Related: 16 Common Tomato Plant Diseases That Can Wreak Havoc On Your Crop

What causes blossom end rot?

The primary cause of blossom end rot is a calcium deficiency in developing fruits. Many gardeners mistakenly believe that this is due to low calcium levels in the soil, but the actual issue is the plant’s inability to absorb calcium because of fluctuations in soil moisture levels.

Rapid plant growth, drought stress, high levels of salts in the soil, and acidic soil conditions can exacerbate this problem.

What does blossom end rot look like?

Disease of tomatoes. Blossom end rot on the fruit. Damaged red tomato in the farmer hand. Close-up. Crop problems. Blurred agricultural background. Low key.
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Blossom end rot initially appears as a small, moist spot at the blossom end of the fruit, where the flower once attached. As it progresses, the spot enlarges and turns dark brown or black, and the affected area becomes sunken and may take on a leathery texture.

In severe cases of blossom end rot, the entire fruit may become distorted and unusable.

It is important to note that blossom end rot affects the fruit only and does not spread to other parts of the plant. This physiological condition is not infectious and can normally be reversed by addressing the initial cause.

Preventing Blossom End Rot

1) Maintain consistent soil moisture

Inconsistent moisture levels in the soil are the primary cause of blossom end rot in tomatoes and other fruiting vegetables. Plant roots need moisture to access calcium in the soil, so dry periods lead to a calcium deficiency.

Here are some ways in which you can ensure the soil around plants prone to blossom end rot stays moist without becoming waterlogged:


Organic mulches reduce evaporation from the soil surface, helping retain moisture even during hot weather. They are also gradually incorporated into the soil below, improving the soil structure and water retention properties.

The best organic mulches for vegetable crops are well-rotted compost, chopped straw, leaf mold, or dried grass clippings. 10 Cheap Mulch Ideas for a Lush Garden


Tomatoes and other fruiting vegetable crops must be watered evenly and deeply to promote healthy root development and calcium uptake. In addition, they should always be watered at ground level, as moisture and humidity around the leaves and stems increase the risk of fungal diseases.

Aim to provide one inch of water per week to tomatoes, peppers, eggplants, and squash, ideally using a soaker hose or drip irrigation system.

Related: How to Water Your Garden The Right Way

Watering tomatoes plant in greenhouse garden. Hand with watering can in greenhouse watering the tomato. Close up.
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2) Maintain correct nutrient levels

If blossom end rot is a recurrent problem in your vegetable plot, it is worth carrying out a soil test to check nutrient levels and pH. Although most soils have enough calcium to meet your plants’ needs, other nutrient imbalances can affect how efficiently roots can access this essential nutrient:

  • High levels of nitrogen can interfere with plants’ calcium uptake. Use a balanced fertilizer and avoid excessive use of nitrogen-rich fertilizers on tomato crops.
  • If soil tests show that your plot is deficient in calcium, amend the soil with gypsum or lime before planting.
  • Maintain a soil pH between 6.5 and 7.0 to optimize calcium availability for plants.
  • High salt levels in the soil can interfere with calcium uptake. Increasing irrigation can correct this issue.

The best way to ensure your soil contains the correct levels of nutrients for tomatoes and other fruiting crops is to apply a generous layer of well-rotted organic compost at the start of every growing season. Then, as the plants begin producing fruit and require extra nutrients, start applying a good-quality fertilizer every two weeks.

Red pepper on a plant. Gardening
Image Credit: Deposit Photos

3) Plant management

Blossom end rot sometimes occurs because of issues with how we have planted and maintained our crops. This can lead to limited water and nutrient availability and reduced yields of tomatoes, peppers, and other fruiting vegetable crops.

To reduce the risk of blossom end rot, ensure that all plants are spaced adequately to minimize competition for water and nutrients. Carry out any recommended pruning and use plant supports to reduce stress on heavy-fruiting branches.

Avoid disturbing the soil around the base of plants, as this can destroy delicate root systems and lead to calcium deficiencies.

Carry out good crop rotation practices to reduce nutrient imbalances in the soil that contribute to blossom end rot. If you find that blossom end rot occurs no matter what steps you take, consider buying resistant plant varieties that are less susceptible to this troublesome problem.

Related: Grow Juicier, Tastier Tomatoes with These 15 Companion Plants

What to do if your plants have blossom end rot

If you spot the early signs of blossom end rot on your tomatoes, eggplants, or other fruiting crops, don’t panic! This condition can easily be reversed by ensuring that plants have adequate water and resolving any nutrient imbalances in the soil. Increase the frequency of watering and consider applying organic mulch to help improve water retention.

While you’re waiting for your blossom end rot management strategy to kick in, it is worth removing any fruits that appear to be affected.

This will prevent the plant from wasting resources on growing inedible fruit and stimulate it to start producing new flowers, ready for a bountiful harvest later in the season.

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