Updated at: 24-10-2022 - By: Sienna Lewis

My greenhouse’s potting soil is always sprouting some sort of white substance. There could be a variety of things that could happen in the greenhouse, including the presence of components on plants. Here are the specifics of this issue and how you can fix it.

Moist, dark, and stuffy conditions are ideal breeding grounds for mold and other fungal illnesses. Sadly, it’s very easy to establish these conditions, especially when planting indoors. “” The following are things to stay away from:

What Causes Mold Growth on Houseplant Soil?


Too much water will be consumed by fungus and can cause root rot in potted plants. Plants that live in a home tend to need less water than those that live outside. Indoor plants, on the other hand, benefit from indirect sunlight and the confines of a home’s interior, which prevents them from drying out as rapidly as plants outside.

Poor Drainage

Excessive wetness might also be caused by poor water drainage. Incorrect pot size, absence of drainage holes, and dense soil are all factors that contribute to poor drainage.

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PlantTAGG CEO and creator Andrew Levi highlights the importance of using the correct pot size. It’s more likely that you will observe root rot if the roots of your plant are exposed in an enormous pot, he explains. Before you go out and get a container, make sure you know exactly how big your plant is. Bring it along to the garden center to see whether it will fit before you buy it. Some plants do better in pots than others.

Drainage holes are sometimes missing from attractive pots, allowing water to seep through the soil and out the bottom. As a result, mold and fungus thrive in and around the roots when they are absent. It is advised by DeVore to use containers with a number of drain holes of 1/4-1/2 inch diameter.

The water will have a hard time getting out of your soil if it is too dense. For container planting, potting soil is specifically designed. The perlite and peat moss, both of which are lightweight, aid in the drainage of excess water. You can use peat moss as an amendment to compacted soil, or you can simply repot your plant in a higher-quality potting mix.

Poor Air Circulation

In the winter, when windows are closed, indoor plants often lack proper air circulation. This problem is exacerbated in plants that are housed in dimly lit areas or on crowded shelves. Air movement helps plants dry out between waterings.

Contaminated Soil

The lack of appropriate air circulation for indoor plants can be exacerbated during the winter months when windows are closed. In particular, plants that are housed in dimly lit areas or on crowded shelves are at risk. Plants might dry up between waterings thanks to the movement of the air.

Decomposing Leaves on Surface

The decomposition of plant tissue is a food source for mold and other fungal illnesses, therefore a pile of dead leaves in the soil encourages mold. Remove the plant’s dead parts before they build up at its base. In order to cut down on yard waste, use fallen leaves as mulch outside.

What Is The White Mold On My Soil?

Saprophytic fungi, such as the white mold you see growing on the potting soil’s surface, are normally harmless. Although it appears that the fungus is harming your plant, this is an unusual occurrence that may indicate that there are issues with the way your crops are being grown in the greenhouse.

There are a number of possible explanations for the growth of the fungus, including overwatering, poor drainage, and even tainted potting soil. In your damp soil, they feed on rotting organisms.

White mold can also grow on the soil of your potted plants, so be on the lookout for it. Insufficient drainage and inadequate air circulation are the most common causes of these conditions, which result in moist and humid conditions. These conditions are perfect for the growth of white mold.

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What To Do With This

How do I get rid of the white thing that continues sprouting in my greenhouse’s potting soil? Definitely.

The following are possible methods you could take to deal with the ongoing issue:

  • Remove any plants that appear to be diseased. It’s too late to save the plants if the garden is already infested. However, this can be avoided. To prevent the fungus from spreading, remove the sick plants and dispose of them in the garbage rather than the compost pile. At the conclusion of the season, remove all of the leaves and other waste from the garden. It’s also possible to remove the perennials, remove the annuals, and rake up the leaves as you remove the waste. As winter approaches, fungus may feast on your dead plants.
  • Crop rotation is a must. Having a variety of crops in different parts of the garden is essential to avoiding these occurrences. Wherever you have herbs or marigolds or potatoes, move the tomatoes to that location. If your garden isn’t large enough, you can wait a year before planting anything new and move your tomatoes to an area where the fungus won’t be able to flourish. Containers can be used to grow plants.
  • Crops resistant to disease are available. Herbs and vegetables that have been developed to be resistant to soil-borne illnesses are available for home cultivation.
  • Fungicide should be on hand. As a line of defense for the plantation, your greenhouse plants will benefit from the addition of a fungicide.

How Do You Kill Fungus In Soil?

The fungus has been dealt with, but the issue of totally eradicating them is still up for debate. This must be dealt with as soon as possible.

The plants may not develop well if the fungus is allowed to flourish, so don’t put yourself through the hassle of cultivating them. Plants and soil that contain pathogen elements should be thrown away and replaced with new ones as soon as possible.

Unsure of the kind of fungus

What you can do if you’re unsure about the fungus that’s wreaking havoc in your greenhouse soil is this. The first step is to have your soil tested by your local office. A network of universities, federal agencies, and state governments could work together to teach people how to grow healthier gardens, for example.

Does Cinnamon Kill Mold In Soil?

To get rid of or fully eliminate the mold’s soil, Cinnamon may be of use. Most of the problems can be solved by physically removing the fungus, including the topsoil layer, or disposing of it. Wearing a mask is absolutely necessary if you are allergic to anything or have difficulty breathing.

After that, you’ll need to be able to evenly distribute cinnamon powder over the top of the soil. Due to cinnamon’s powerful antifungal properties, it is able to eradicate any lingering fungus.

Avoid re-watering the area until the topsoil has totally dried up. Ground cinnamon should no longer be applied directly to the soil after the fungus has been eliminated. Your garden soil will be devoid of beneficial fungi as a result of this treatment.

What Else Can You Do?

  • Using a saucer filled with water for more than five minutes is a bad idea. Excessive moisture should be removed.
  • To speed up the drying process, place plants in direct sunlight or bright artificial light.
  • It’s best to expose the plant to fresh air and sunlight if you notice any mold growing on it. When you bring the plant back inside, place it in a position that is somewhat brighter and a little more windy.
  • Alternatively, you might move the plant to a larger pot filled with fresh soil. When selecting a pot, look for one with numerous plant holes for drainage.

Is It Safe to Use a Bag of Old, Moldy Potting Soil?

When you don’t use all of the potting soil at once, you may notice that fuzzy white stuff has sprouted inside the bag when you go to use some more later. In certain cases, you may notice the same thing when you buy a new bag of potting soil and bring it home. Is it still possible to make use of the soil?

  • As long as you are planting, transplanting, or simply reseeding, sure. Simply mix the contents of the bag and re-incorporate the white items into the dark ones before using it. You may also want to add some fresh compost to the mix. After cutting open the bag and exposing it to the sun and air, rotate it every few hours for at least a day or two. Fresh compost can also be added to the mix.
  • For seed-sowing purposes, however, such soil should be avoided. In order to give the seedlings a fighting chance against the mold, it’s preferable to start them in some fresh dirt.

Is the White Stuff Growing in Your Potted Plants Dangerous to Humans?

Most of us instinctively cover our mouths and flee when we spot mold. However, despite what most mold removal firms would have you believe, the mold in your potted plants is not very harmful to humans.

You may not want to take any chances if you have a severe allergic reaction to mold. Allergic symptoms have been reported in response to the spores, according to some.

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How to Prevent Mold From Growing in Soil

There is no way to completely remove mold. It’s natural to see mold spores in soil, but they’re usually safe. The real threats to your plant are heat, humidity, and low ventilation. Mold spores mature into adult fungi under these conditions and produce even more spores. Because they retain more moisture, indoor planters and container gardens have become increasingly popular as hosts. Mold can be prevented by following the easy measures outlined here:

  1. There is no way to completely eradicate mold. It’s usual for soil to have mold spores, but they’re generally safe. Your plant is most at risk from high temperatures, high humidity, and a lack of enough airflow. As the mold spores mature, they release even more spores into the air. Because they retain more moisture, indoor planters and container gardens have become increasingly popular as hosts. Here are a few tips to keep mold at bay:
  2. In order to reduce the amount of moisture in the air, you should open the windows. Mold flourishes in stale environments, which are created by the combination of these two factors. In addition to reducing humidity by avoiding overwatering, using a small fan or placing your plants in more sunny, well-ventilated areas can help further reduce moisture in the soil.


My greenhouse’s potting soil is always sprouting some sort of white substance. Potting soil and mixtures frequently contain fungus, and this is often due to excessive amounts of bark or wood chips in the soil. In general, the fungus prefers to eat them and other decomposing organic material.

When plants are cultivated inside, excessive watering might cause problems with the soil. Because of the lack of sunlight, the top layer of soil in these regions never dries up completely. As long as the conditions are right, the fungus can grow.