Plant diseases

Recognize, treat and prevent flower end rot in tomatoes


The end of blight is caused by calcium deficiency and mainly affects older tomato varieties. With the right care, you can prevent the disease.

© Pixelmixel /

Tomatoes are one of the most popular plants in the vegetable garden. The joy of a rich harvest is clouded when brown spots suddenly appear on the fruit. Tomatoes can be affected by end-of-flower rot at any stage of ripeness. The following article reveals what the disease is all about, how the hobby gardener deals with it and what preventive measures are advisable.

What is the final blight?

It is a metabolic disorder. In addition to tomatoes, zucchini or cucumber can also be affected. The final blight of the flower arises when calcium deficiency causes the tomato berries to rot from below. The dark spots only form on the underside of the fruit. This is due to the fact that the fruits ripen on the flower base.

The tissue changes and appears sunken and waxy. As the process progresses, the pulp dries out and hardens. The previously brownish spots turn black.

Tip: Only individual fruits are affected by the blight. The entire plant is not endangered.

If there is a calcium deficiency, the cell walls lose structure and collapse. Ultimately, the brown spots are parts of the tissue that have already died. Similar symptoms are also caused by excessive humidity.

Are there any particularly vulnerable tomato varieties?

The tomato originally comes from the Andean region and grows in hot and dry locations. Therefore, especially old tomato varieties have problems with the climate in our latitudes. Ox-heart or egg tomatoes are particularly susceptible to end-of-flower rot as well as brown and herb blight.

Tip: Large and fleshy tomatoes are most commonly affected.

Various new varieties are well adapted to the local climate, such as:

  • Phantasia
  • Vilma
  • Philona
  • Romello
  • Picolino

Recognize end rot

A typical identifier is the brown dots on the fruit set. In order to recognize these in good time, the tomatoes should occasionally be turned up or viewed from below. The spots change color darker, the fabric dries out and ultimately the complete fear changes color.

In midsummer, there is a particularly high risk of end rot. If the disease remains undetected, the fruit falls off the bush.

Fight end rot

The pH of the soil can provide information about the calcium content in the soil - © Deyan Georgiev /

Since the disease only affects individual fruits and spares the stems and roots of the plants, the final blight is easy to treat and the harvest is not in danger.

If you keep an eye on your tomatoes, you will recognize the abnormalities in the fruit described in good time. All infested tomatoes are removed from the shrub. In most cases, the irrigation has been insufficient because the tomato plants absorb the necessary calcium via the irrigation water.

The determination of the pH value provides information about the condition of the soil. This can be determined by using the appropriate sets that are available in any hardware store. If the substrate is too acidic, the proportion of potassium and magnesium increases. These two substances have the property of binding calcium.

If the soil is too acidic, lime can be used. Lime can be spread in the form of stone powder and lead to an increase in the pH value. The fertilizer is applied to the leaves. If their needs are met, the calcium absorbed through the roots is fed into the tomato fruits.


  • remove infested fruit
  • Increase the amount of water
  • Provide acidic soil with lime

What happens to the infested fruit?

If the disease is recognized in time, only small parts of the fruit are affected. The taste of the tomatoes is not affected. After the brown spots have been generously cut out with the knife, the tomato can be consumed and processed as usual.

However, the tomatoes are often attacked at an early stage of development. In this case, further cultivation is not worthwhile. The fruits are removed and disposed of. This can happen on the compost because the disease is not caused by fungi or bacteria.

The main thing now is to water and fertilize the plant sufficiently and thus to encourage rapid crop rotation.

Prevent end-of-flower rot

The preventive measures start with the selection of the plants. New varieties adapted to the local climate are less at risk of suffering from end-of-flower rot. It can also be exciting to grow the aromatic new varieties.

Tomatoes are sensitive to moisture. The leaves should be protected from the rain as much as possible. Here greenhouses, shelters or special film tunnels are suitable as cover.

The plants should be kept evenly moist. However, you should avoid waterlogging. The substrate should be enriched with a special tomato fertilizer. This gives the plants all the necessary nutrients in the required concentration.

To ensure that the fruits are supplied with sufficient nutrients and that the strength does not predominantly get into the leaves, excess leaves can be removed from the tomato plants.