Mold in greenhouse: How to control and prevent

Mold in greenhouse How to control and prevent
Mold in greenhouse How to control and prevent

A greenhouse is an enclosed space in which the soil is under special conditions. Compared to the open-air environment, greenhouse soils have no possibility of self-healing. All biological processes occur faster in them, and negative flora and fauna accumulate more intensively.
In order to provide optimal conditions for the growth of the necessary products, the rapidly depleting soil constantly needs replenishment of nutrients and water, sufficient light and air, and soil temperature.
Changes in air humidity combined with high temperatures can promote rapid growth of mold in greenhouses, affecting living plants, as well as damaging any woody structure of the greenhouse or shed, with very negative effects on human health.


In the plant system, fungi are identified as a separate kingdom in biological nature. In total, there are more than 250 species of fungi, divided into different groups and orders according to their biological properties. In the modern international classification, mycorrhizal fungi (Fungi bissoidei) are classified in order 6 and are represented mainly by unicellular and less often by multicellular organisms. They are called microfungi because of the small size of their individual representatives.

Usually, mycorrhizal fungi grow in large colonies that exhibit the appearance of branching hyphae without large substrates. Most molds are classified as specialized or parthenogenic parasites (i.e., parasites that are able to live in the host environment or live independently). Spores of mycorrhizal fungi are able to survive in space, permafrost, and high radiation conditions. Only some species die after being exposed to temperatures above 212°F (100°C) for at least 3 hours.


Mycorrhizal fungi can live and reproduce in water or soil. Their extensive colonies are ubiquitous in warm, moist places with adequate nutrient media. This medium for mycorrhizal fungi in greenhouse soil. The quality of the substrate determines the health of the plants, which in turn depends on the quality of the grown seedlings. Changes in greenhouse soil quality parameters have a negative impact on the growth and development of seedlings. The main manifestation of greenhouse fungal infestation of seedlings is the appearance of white patches on the greenhouse soil, which are the mycelium of harmful fungi.


Cultivation of crops and seedlings in protected conditions in violation of the rules of agricultural engineering leads to the main development of pathogenic microflora.

The mold spreads mainly in dirty rooms. Therefore, the greenhouse must be systematically cleaned and treated with antifungal agents (cleaning, bleaching, painting, etc.).


Tiny spores are easily spread by air currents and can remain dormant for dozens or more hours. Under the right conditions, they begin to grow and multiply rapidly, taking over living plants with soft tissue (seedlings of vegetable crops, tomatoes, cucumbers, etc.).

The optimal conditions for the spread of harmful fungi are as follows.

  1. In a closed room with air humidity higher than 95%.
  2. Room temperature 68-71 °F (20-22 °С).
  3. Lack of ventilation and poor ventilation.
  4. Increase soil humidity after irrigation, water retention in the root system, caused by incorrect watering, water leakage at damaged watering pipes.
  5. Insufficient light (overcast weather, absence of supplementary lighting, insufficient UV radiation from thickened vegetation).


Mold is associated with the processes of bio-erosion and vegetation decomposition. As a result, mold growth is strongest during the fall. However, the single use of the preparation does not provide an effect against mycorrhizal fungi. To create optimal conditions for plant growth and development on protected sites, a set of measures is needed.

After the fall harvest, it is necessary to disinfect the greenhouse/garden in preparation for the next season’s nursery and seedling-free vegetable crops. Greenhouses and soil can be disinfected in several ways.

One effective way to destroy mold is to treat the greenhouse with an oxidized sulfuric acid firebox.

If mold was found in the greenhouse the previous year, you should repeat the disinfection treatment in the spring with a solution of manganese with an added binder (you can use soap).

During the cultivation of seedlings and crops, it is necessary to constantly control air and soil moisture indicators.

Keep the irrigation system in good working order. Avoid over-watering. If seedlings develop black feet (one of the indicators of overwatering), sprinkle dry sand in the soil under the seedlings. Ventilate the greenhouse thoroughly (no drafts).

Molds do not tolerate alkaline conditions, so for all plants under greenhouse soil 2-3 times a season, 3-4 weeks apart, you need to use a mixture of ash and charcoal (1:1), ground to a powder.

If the soil appears moldy (especially compacted), you can treat the greenhouse soil with peatin, which is represented by a dried block of high moisture peat. Peat contains a synthetic polymer that acts as a soil loosening agent and increases its volume several times during the soaking period. To neutralize the acidity of the soil, it is treated with a copper solution of peat, to which a water-soluble mineral fertilizer is added.

To prevent damage to plants by fungal diseases (blackleg, Fusarium wilt, root rot, etc.), treat plants with a bio fungicide, using Benomyl or similar as recommended, 8-10 days after germination. The same bio fungicide can be used for soil treatment under the plants. Treatment with biocides (soil and plant) should be repeated after 15-20 days unless other terms are specified in the recommendations.

When growing seedlings at home, it is best to use special soil, especially for beginner gardeners. These soils are specially treated to prevent pests and diseases and are fertilized according to agricultural techniques.

Cultivation of seedlings and seedless crops under greenhouse and home conditions requires strict adherence to agronomic measures. Otherwise, the protective measures taken may not produce the desired results.

Remember, molds are not harmful to human health. But a greenhouse infected with mold can cause bronchitis, bronchial asthma, allergic rhinitis, and otitis media. Mold spores deposited in the lungs can cause lung disease up to cancer. Foods, including mold-affected fruits and vegetables, should not be eaten.

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Title: Mold in greenhouse: How to control and prevent
Source: ThumbGarden
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