What to do if the onion rots in the garden and why it happens

Often, gardeners are faced with the problem of onion rotting. Plants take on a sick appearance, and the harvest is lost before our eyes. Methods for solving the problem are selected depending on the causes of this phenomenon. Timely solution of the problem will save the harvest. Why the onion rots in the garden and what to do with it, we will tell in the article.

For what reasons do onions rot in the garden

Most of the causes of onion rot are soil related. Early detection of negative factors will save harvest from death.

What to do if the onion rots in the garden and why it happens

Excess moisture

Excessive soil moisture is destructive for a plant. Be sure to monitor this rate and do not water too often. Constant rains also cause waterlogging of the soil. In this case, they consider in advance the removal of excess liquid from the beds using drainage in the form of expanded clay or coarse sand, which is introduced into the soil before planting.

Failure to comply with crop rotation

Growing onions in one place from year to year is unacceptable - this leads to the accumulation of pathogenic microorganisms and pests in the soil. When planting, they fall on the plant through the soil and begin to destroy it.

Reference. Lack of crop rotation leads to land impoverishment. The plant lacks minerals, which provokes the process of decay.

Excess nitrogen in the soil

Onions need nitrogen at the beginning of growth. This contributes to a set of green mass. In the future, the plant does not need it and remains in the soil. Application of complex fertilizers, which contain nitrogen, will lead to its accumulation in the soil. Excess trace minerals will soften the bulbs. In the future, they will begin to rot.

Infected planting material

Signs of infected planting material:

  • the upper scales are moist;
  • sevok has an uncharacteristic smell;
  • the covering husk of the wrong color;
  • visible lesions on the head and bottom of the bow.


Decay processes are caused by the development of bacterial or fungal infections. Provoking factors are damp weather, high soil moisture, improper care.

What to do if the onion rots in the garden and why it happens

Basically, the plant is affected by the following diseases:

  1. Cercosporosis - fungal disease of onion feathers. It is characterized by the appearance of clear gray spots with a thin yellow border. When neglected, the leaves turn yellow and die off.
  2. Cervical rot - fungal disease. It starts from the neck of the bulb. The scales become wrinkled, and the inner layer decays, becoming covered with a gray coating with black dots. On the cut, the onion has a boiled appearance.
  3. White rot - fungal infection. Develop at a temperature of + 20 ... + 24 ° C. Yellowing and subsequent death of the leaves is characteristic. The onion quickly withers and dies. A fluffy bloom and soft rot form on the roots.
  4. Powdery mildew - a fungal infection starting from the outside of the feathers. The plant is exhausted and dies. The stems are covered with brown spots.
  5. Fusarium rot - a fungal infection that gets on the plant from the soil: first to the roots, then up to the head and feathers. This is the most rare reason why the bottom of an onion rots and becomes watery.


The main damage to the crop is caused by:

  1. Onion flies... Insect 6-8 mm long, light gray. Outwardly similar to house flies. The plant slows down growth, feathers turn yellow, wither, dry. An unpleasant smell comes from onions.

    What to do if the onion rots in the garden and why it happens
    Onion fly
  2. Stem and bulb nematodes... Small worms that live in the topsoil.The plant slows down in growth, the process of rotting of feathers, stems and roots begins.

    What to do if the onion rots in the garden and why it happens
    Onion nematode
  3. Weevils. Insects with a black strong convex body up to 2-2.7 mm long. At the initial stage, leaves are affected. After 14-20 days, through the gnawed feathers, they descend into the ground to lay eggs.

How to deal with decay

The choice of treatment method depends on the degree of damage. At the initial stages, folk methods of combating onion rotting are effective. In advanced cases, chemical preparations are used.

Traditional methods

Publicly available methods of struggle are used in the initial stages of the disease. They are easy to use and safe.

In rainy weather, the beds are covered with foil. This reduces soil moisture. The second method is drainage in the form of a layer of sand or expanded clay at the bottom of the garden.

What to do if the onion rots in the garden and why it happens

The amount of nitrogen in the soil is reduced by reducing irrigation. Observe the frequency of nitrogen, potassium and phosphorus addition. Nitrogen forms a succulent feather, phosphorus forms a strong onion head. Potassium improves taste, keeping quality and resistance to pests.


  1. Nitrogen is applied at the beginning of the growth period, in the phase of 1-2 leaves. To do this, 10 g of urea is dissolved in 10 liters of water and the garden is watered immediately after planting the onion.
  2. Phosphorus is added in the middle and at the end of growth. To do this, take 20 g of superphosphate and dilute in 10 liters of water.
  3. Potassium is fertilized at planting (half the norm), the rest is divided by 2 times and applied in the middle and end of the period cultivation... At the beginning of the season, 20 g of potassium sulfate is mixed with 10 liters of water. In autumn, after harvesting, a solution of 12 g of potassium chloride and 10 liters of water is added.

Disease control:

  1. Cercosporosis is treated with fermented herb infusion. It is prepared by steaming 1/2 bucket of chopped greens with boiling water. The mixture is left for several days. Then the beds are filtered and watered 2 times with a break of 2 weeks.
  2. White rot is treated with milk whey (1.5 tsp dissolve in 1.5 l. copper sulfate and 3.5 l of water). The resulting mixture is watered every 14 days until the signs of damage disappear.
  3. Wood ash helps fight powdery mildew... 2 tbsp. pour 2 liters of boiling water, insist, filter. Dissolve in a bucket of water and spray the beds. The herb infusion used to combat cercosporosis also helps. A solution of 100 g of raw materials per 1 liter of water has a detrimental effect on fungal spores. Apply the remedy every 14 days until the signs of damage disappear.
  4. The weevil is taken out with burlap, cut into 10 cm wide ribbons. In the evening they are laid out around the bulbs, in the morning they are removed - the pest will get entangled in them.


Insecticides are effective when the lesion is critical. The drugs will cope with pests and will save the harvest. The main condition is to observe the dosage:

  1. For cercosporosis and powdery mildew, "Fitosporin" is used. 10-15 g of powder are diluted in 10 liters of water. The crops are sprayed at intervals of 14 days. In rainy weather, treatment is carried out once a week.
  2. White rot is well treated with Fundazol. 10 g of the drug is dissolved in 10 l of water and the beds are watered every 14 days.
  3. Cervical rot is treated with Bordeaux liquid - 100 g per 10 liters of water. The resulting composition is watered once the beds.
  4. The onion weevil is fought with "Karbofos" - 60 g of the drug per 10 liters of water. The beds are sprayed once during the growing season. The prepared mixture is designed to process 10 sq. m.

Prevention measures

What to do if the onion rots in the garden and why it happens

Prevention measures include:

  1. Compliance with crop rotation. Onions are planted in the previous place no earlier than 3-4 years later.
  2. Selection of varieties resistant to diseases. These include Supra, Farmer Late, Stardust F1, Comet, Goliath, Erica, Stutti, Sterling F1.
  3. Treatment of seeds and soil before sowing. The beds are doused with boiling water and covered with foil for 4 days. Before planting, watered with "Fitosporin" (5 g of powder 10 liters of water). The bulbs are soaked for an hour in a warm (+ 45 ° C) pink solution of potassium permanganate.
  4. Loosening and weeding is carried out every 2 weeks.
  5. Planting carrots and scented tobacco as neighbors (save from onion flies), calendula, marigolds and nasturtium (save from nematode infection).


Among the main reasons for rotting onions in the garden are high humidity, non-observance of crop rotation, excess nitrogen in the soil, contaminated planting material. When fighting diseases and pests, folk methods and chemicals are used. The first option is effective in the early stages, the chemicals are applied later. By following simple preventive measures, rotting is easy to avoid.

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