When the potting soil goes mouldy: This is how you remove the fungal lawn

 Almost every hobby gardener has experienced this: the potting soil of the freshly repotted house plant suddenly turns mouldy. We explain how the mould develops and what can be done about it.

First of all, you must clarify whether you are really dealing with mould on your potting soil: If you live in a region with hard, i.e. lime-rich tap water, 

the deposits can also be lime or other minerals - especially if the plants in the room are on a windowsill that is warm enough to heat. 

The irrigation water rises up through the pot ball, evaporates at the surface and leaves the minerals dissolved in it behind. 

Simply take a wooden stick and scrape off a little of the supposed mould. If it is hard and crumbly, these are mineral deposits. 

They are a purely aesthetic problem and can easily be scraped off the surface with a spoon or a planting shovel. 

Then, if necessary, fill the pot with a little fresh potting soil and you have solved the problem for the time being.

A fluffy, soft, white coating is more difficult, 

because this is usually mould: the mould does not usually only settle on the surface of the pot ball, but also permeates the inside with its mycelium. 

They often also spread a slightly musty smell. Although not all moulds are problematic, 

some are classified as hazardous to health if their spores accumulate in higher concentrations in the room air. 

In people with chronic or allergic respiratory diseases, the mould spores can also trigger asthma attacks.

At a glance: When Potting Soil Mould

✔Take the affected pot outside and air the room

✔Pot the plant and scrape off the mouldy soil

✔Clean the pot thoroughly with a brush and vinegar solution

✔Pot the plant with new, high-quality soil

 In principle, any potting soil with a higher humus content can become mouldy. 

In nature, moulds have an important function as destructors - this is the biological term for organisms that live on the decomposition of dead organic matter. 

However, an excessive spread of individual species is an indication that the potting soil has lost its biological balance. 

This happens above all when the water supply is too good, 

because mould spreads particularly quickly in permanently damp environments. 

Experience also shows that poor quality potting soil with a high compost and black peat content is particularly susceptible to mould. 

One reason is that the structure of cheap soils is often not stable and deteriorates rapidly with age. 

With decreasing aeration, the susceptibility to mould growth then increases.

How do you remove the mould in the flower pot?

First, you should take the flower pot with the mouldy potting soil outside and then air the room or apartment thoroughly. 

Outside, pot the houseplant and scrape off the loose, mouldy soil from the surface of the pot ball with a dustpan. 

Then remove all the loose soil as far as possible so that only the intensively rooted rest of the bale remains. 

During the dormancy period in autumn and winter, 

you can now reduce the root ball of robust houseplants by about a quarter to a third by cutting off several thin slices at the bottom and sides with an old bread knife. 

After this procedure, take the pot and clean it thoroughly from the inside and outside with a brush and warm vinegar solution.

Then repot your plant with new, high-quality indoor plant soil and return it to its original location. 

Make sure that the soil has as high a mineral content as possible, 

such as sand or lava grit, and if in doubt, mix in a handful or two handfuls of clay granulate.

It is also important that the bottom of the planter has enough drainage holes. 

They will not clog up so easily if you cover them with fragments of clay before filling the expanded clay. 

Depending on the pot size, a layer of expanded clay about two to three fingers high ensures that excess water cannot accumulate in the soil.

How do you prevent new mould infestation?

With good drainage and high-quality potting soil, you have already created the most important conditions to prevent mould from spreading again. 

Now the most important thing is to dose the water quantity correctly. 

It is better to water your houseplant a little too little than to keep the pot ball constantly moist. 

It will only need new water again when the surface of the bale has dried out well. 

You can easily check this by briefly checking the soil moisture with your finger or by inserting a watering indicator from a specialist shop.

Especially during the dormancy period in the autumn and winter months, the water requirements of many indoor plants are extremely low. 

During this period, you should therefore reduce the water supply a little further and spray the leaves with rainwater more often to help them cope better with the dry heating air in the room. 

Irrigation via the coaster is also helpful: pour small amounts of water several times until the pot ball does not absorb any more water, and pour the rest away. 

The next watering is only done when the surface is dry.