Updated at: 27-05-2022 - By: Helen Skeates

Even with plant care, molds may be a major source of frustration for homeowners like you. There is nothing else on your mind but finding a way to get rid of mold on germinating seeds before it does any harm to your healthy seedlings.

There is no need for you to worry about this, as molds are actually harmless to your seeds if they are caught early enough. It’s a problem that beginner gardeners, as well as those who consider themselves “experts,” may run into.

However, it is possible that your seedlings are dying out because of the conditions or surroundings that are allowing the mold to thrive.

You’re in luck, because this article has five simple procedures for removing mold from your seeds. In addition, you’ll learn how to avoid mildew in the first place.

Does Mold In Plant Soil Hurt Seedlings?

Mycotoxins aren’t dangerous to your seedlings, even if you observe fuzzy white mold developing in the soil.

4 Ways 2 Manage Mold & Fungi - Sun, Dry, Cinnamon, Peppermint Oil: Starting Vegetable Seeds Indoors - YouTube

It’s a good sign if you see mold around your seedlings if the conditions are correct for preventing sickness.

A unpleasant condition like that is the last thing you need!

It’s caused by a fungus that causes your plant’s stems to snap and it toppled over in a matter of days. You may, however, learn how to deal with and avoid damping off in the future.

What Causes White Mold In Seed Trays

However, despite the fact that white mold is rather safe for plants, it doesn’t look very appealing, does it? Mold is something I, for one, do not want in my house, and I would wager that you feel the same way.

To keep your seedlings healthy, it’s also a warning that something is wrong with your seed starting setup.

Overwatering, overcrowding, keeping seedlings warm, and a lack of airflow are the most common causes of white mold on seed starting soil.

Everything to Know About Mold On Seedlings

In the garden, mold is a constant issue, particularly when starting seeds inside. It’s easy for mold to take up residence in your seed trays because it’s everywhere.

To thrive, mold prefers the damp and warm conditions that plants require to grow properly. To ensure that all of your seeds sprout and grow to maturity, you must eradicate mold from your seed trays as soon as possible.

Here are some frequently asked questions and the associated solutions to assist you better understand the mold on seedlings issue.

Will Moldy Seeds Germinate?

The first thing you notice when you open a packet of seeds is mold forming on the top. What’s the point of these seeds?

The response is that the seeds’ inside may be fine as long as the outer casing is still solid and not mushy.

You must thoroughly clean your potting trays before planting moldy seeds in order to prevent the spread of molds and fungi.

After spreading the seeds on a tray, use one of the following mists to clean moldy seeds:

  • Vinegar that has been distilled into a clear liquid.
  • Bleach (H2O2)
  • Rubbing alcohol (isopropyl alcohol)

Continue to spray and stir until all of the seeds have been soaked.

Replant the seeds and make sure they receive plenty of sunlight. While the liquid will drain off the seeds rapidly, enough time will be given for the seeds to be disinfected and spores killed.

There is no guarantee that moldy seeds will germinate, so expect a lower germination rate and hope for the best.

Is Mold Bad For Seedlings?

Yes, mold can be harmful to seedlings if it isn’t treated quickly.

It’s disheartening to have to throw out a whole seedling tray since the mold has taken over.

Seedlings can be infected by a variety of molds and fungus.

  • Saprophytic
  • Rhizoctonia
  • Fusarium
  • A mildew with a downy spore count.
  • Pythium

As a seedling grower, you should be familiar with the various varieties of mold and fungi that could be lurking in your seedlings.

There are several molds that don’t immediately harm seedlings. A wide variety of mould feed on the soil’s moist organic content.

Because even “plant-safe” mold depletes the soil of the minerals seedlings need to thrive, there is an issue here.

As a result, mold must be removed as soon as possible because it is still harmful to the development of your seedlings.

Causes Of Mold Growth On Starting Seeds

Why don’t we have a look at the factors that contribute to mold growth on your growing seeds before we begin the mold removal process?

Poor ventilation

The temperature around the seedlings is the most common cause of mold growth. The plot area becomes more humid when there is not enough ventilation or the temperature is too high.

Mold thrives in a moist environment, but the same conditions are ideal for seed germination.

It’s possible that molds would thrive in such a moist environment. You may come across the white fuzzy mold, which is one of the most prevalent types.


Excessive watering of your plants might sometimes result in moldy seeds. Repetitive watering of your seeds ensures that your soil is well-hydrated, allowing your plants to thrive.


When you plant too many seeds in the same seedling plot, it might lead to overcrowding and a lack of air circulation. This overpopulation makes the sprouts an accessible target for fungi because of the lack of airflow.

If you’re looking for more information regarding the causes of white molds on plants, check out this helpful article.

Common Seed Starting Problems (and Solutions!) -

Removing Mold On Sprouting Seeds

Having uncovered the root causes of seed mold, you’re ready to tackle the quick and simple solutions for eradicating mildew from your growing seeds.

Step #1. Prepare tools

To remove the molds, you’ll just need a few simple tools. You can remove the white molds from the soil with a little knife or a pointed pencil.

The seed and soil can also benefit from the use of a fan. This will come in handy in the next stage.

A moisture meter can also be used to ensure that the ground isn’t being overwatered.

Step #2. Remove molds using the tool

Remove as many mould as possible by scraping them delicately to begin the process. Then, wipe it down with a paper towel and dispose of it in an environmentally-friendly fashion.

Remove the white mold from the seedlings and soil by following these instructions.

Additionally, it’s possible that you’ll have to remove any seriously diseased soil fragments. Learn how to properly dispose of potting soil by reading this article.

Step #3. Ventilate pot trays

Mold may have grown on your seedling trays as a result of your lid being on top of them. Allow fresh air into your plot by carefully opening the cap on one end.

However, if the seeds have already sprouted, you can remove the cover completely to enable the soil and plant to breathe. Help the ventilation by using a fan.

Step #4. Dry the soil

Let the soil air-dry for a few minutes after opening the lid. In order to avoid excessive humidity, you need ensure that the soil is evenly moistened.

Prevent the soil from drying out completely by allowing it to dry out between waterings. Before watering, check the soil moisture with a moisture meter.

Step #5. Close the heat mat

Turn down the bottom heat once the seeds have grown to avoid damaging your seedlings with excessive heat.

Prevent Mold

Use Soilless Seed Starter

Using a seed beginning mix that contains organic materials, such as compost or soil, is an easy way to introduce a mold problem to your seedlings.

When you remove organic materials from the ground, you disturb the delicate equilibrium that plants need to thrive.

As a result, bacteria and mold spores found in bagged soil mixes can quickly take hold in your seed trays.

To start seeds and early seedlings, use a soilless seed starting mix instead.

You can then move them to larger pots with a more enriched compost mix once they have established themselves.

Use Non-Organic Pots

If you’re looking for a way to keep your plants healthy and thriving, you can consider using natural plant pots like peat pots or even newspaper pots.

Most of us want to utilize environmentally friendly, biodegradable items or repurpose trash.

However, these pots aren’t necessarily the greatest for seedlings. Mold can grow on the container and soil if they remain moist for a lengthy period of time.

Using plastic cell packs and pots may help if you have a problem with mold when starting seeds.

There are several of ours that have been used for at least five years or more, if you get high-quality ones.

Don’t Over Water

A common mistake beginning gardeners make is overwatering their seedlings, which can be fatal to the plants.

Root rot and damping off disease can also be caused by the presence of mold.

Before re-watering, wait until the top layer of soil is dry. After 30 minutes, thoroughly moisten the seedlings and remove any water still present in the seed tray.

When you water, use an organic fungicide to help prevent mold growth as well.

Increase Air Flow

Increasing the flow of air around your seedlings is a simple way to help keep mold from growing on them.

You can do this by using a low-powered fan to circulate air through your plants.

Seedlings’ stems will be strengthened as well as the soil’s surface will be drier as a result. Leaving the fan running all day is not necessary.

Setting a timer for an hour or so each day might be the most straightforward solution.

It’s also a good idea to provide some breathing room between your plants and your light fixture so that they can breathe properly.

How To Get Rid Of White Mold On Seed Starting Soil - Homestead Acres

Disinfect Your Seed Trays And Pots

Seedling trays can be a breeding ground for mold spores and plant diseases, which can remain latent for long periods of time.

It’s always a good idea to thoroughly clean and disinfect your seed starting trays before using them again to ensure that your seedlings get the best possible start.

What Is White Fuzzy Mold On Seedlings?

It is neither blight or damping off that causes seedlings to flip over at the stem’s base when white fuzzy mold is seen on them.

There is no way to preserve your seedlings if damping-off has infected your seedling tray.

White, fuzzy mold that grows on seedlings is most likely a saprophytic fungal infection. Your seedlings aren’t in danger from the mold, so you have time to deal with it.

Tips To Prevent Mold Growth And Regrowth On Germinating Seeds

In spite of your best efforts, molds might re-infest your seeds even after you’ve eliminated them. To prevent this from happening, take note of the following germinating seed care advice.

  1. An oscillating fan can be used to keep the seed patches well-ventilated. However, keep the soil moist.
  2. Your plants will thrive in a well-ventilated space that isn’t directly exposed to sunlight as well. Seeds will thrive if they are exposed to solid indirect light for 12-16 hours a day.
  3. Before utilizing the seed trays, shovels, and other planting instruments, make sure they are clean and sterilized. Rinse and soak them in a solution of bleach and water.

Fungicide properties of hydrogen peroxide can also be found in plants.

  1. When the seedlings in the tray grow overcrowded, pinch and repot them to prevent poor airflow.
  2. Bottom-watering is an option because it allows water to reach the roots directly. Molds can’t grow because the soil isn’t excessively damp.

How To Get Rid Of White Mold On Seed Starting Soil

The four-step technique of removing white mold from seed starting soil is pretty simple and must be completed so that your seeds can grow.

  1. A spoon or knife can be used to scrape away the mold from the soil’s surface. Moldy soil should be removed from your growing space as much as possible, and then placed in a tiny plastic bag to keep the spores away from your plants.
  2. Step two is to open the seedling trays and allow the seedlings to breathe. Popsicle sticks or pencils work well for opening plastic trays that have been covered. As a result, mold will have a harder time re-increasing in the absence of venting. If your seeds have already sprouted, it’s best to leave the lids off to reduce soil dampness.
  3. This step is crucial because a combination of heat and moisture helps the white mold to thrive.
  4. Allowing the soil in the trays to dry completely is the final step because it is excessive moisture that fosters the formation of white mold. Set up a fan to blow across the trays in a well-ventilated room. It can be difficult to maintain an ideal level of soil moisture for the germination of seeds. Soil that is continually moist but not saturated is essential. It’s safer to err on the side of caution and not water again until the top layer of soil has dried completely. Using a watering can is less precise than misting the tray.

If you spread it out on a tarp or piece of cardboard and let it bake in the sun for a day, you can safely reuse old soil that has a white mold problem. Any remaining spores in the soil will be destroyed by the combination of heat and light.

Tips to Keep Mold at Bay

Using a fan to circulate air over your seed trays will help prevent the return of mold.

Instead of watering from the top, try watering your trays from the bottom. Bottom watering is faster at delivering moisture to the roots, but it keeps the soil surface drier, increasing the likelihood of mold growth.

Keep in mind that if you leave the trays submerged in water for more than 20 minutes, they will absorb too much water and wet the soil instead.

How Do You Get Mold Out Of Seed Starter Pots And Trays?

Sterilizing seed starter pots and trays prior to use is the most effective method for removing mold.

I prefer to make a batch of household bleach and water cleanser and store it in a large plastic container.

Let them soak for a few hours before I start seeding my crops. It saves me a lot of time not having to scrub and rinse off each seed container.

Some of my heavy go-to gardening hand tools such as trowels, rakes, and cultivators (these tools need cleaning as well) are used to keep the plastic down or a couple of huge boulders are used instead.

The bleach solution needs to reach every crevice in the trays to kill any mold, fungus, or bacteria that may be hiding there.

Before using or storing, clean the objects thoroughly with water and allow them to air dry.

Fungicide For Seedlings

It is reasonable for new gardeners to be concerned about the safety and efficacy of fungicides when used on seedlings.

Yes, fungicides can be used to prevent mold and fungi from causing harm to your seedlings in the soil.

There are broad-spectrum fungicides on the market that you can use as soon as you notice any mold growth in your seed trays or before planting your seeds.

When it comes to the environment, the concern is that many fungicides contain dangerous synthetic compounds.

Natural DIY fungicides may be made at home, but some of the substances are less efficient than others when it comes to fighting all the many kinds of mold you may meet when gardening.

Using a fungicide on seedlings has both advantages and disadvantages.


  • Improved germination of seedlings
  • As the plant does not have to compete with fungi for nutrients, its development is robust.
  • Higher yields of crops


  • Plant roots can absorb nutrients that are broken down by helpful bacteria killed by fungicides.
  • Soil and water pollution can be exacerbated by the use of fungicides.
  • The use of certain fungicides can pose a risk to human health.

The most important thing to remember is to use fungicides carefully to protect your plants and the environment.

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Will mold kill germinating seeds?

As a result of the widespread popularity of beginning seeds inside, many individuals become discouraged when they encounter difficulties. Fungus (often misunderstood as mold) on top of the seed beginning soil is one of the most common seed starting difficulties, and it can lead to the death of the seedling.

Can seedlings recover from mold?

Symptoms of infection include a lack of roots or white cobweb-like growth on the plant. Because damping off cannot be reversed once seedlings are afflicted, they must be removed. There is a silver lining to this story? Moldy seedlings can be avoided by following some simple guidelines.

How do you treat mold in seeds?

The anti-fungal solution can also be made with 1 tablespoon peroxide and 1 quart of water. The use of chamomile tea or cinnamon sprinkled over the soil surface shortly after planting has proven successful for many organic growers.

Why did my seeds mold?

Because the mold that grows in your seed trays is what eventually kills your seedlings. Overwatering, poor ventilation, excessive heat, and/or overpopulation are the primary culprits.

Why do my sprouting seeds go Mouldy?

Where did all of my sprouts go bad? In a nutshell, your sprouts are over-watered. Mold thrives in moist and stagnant circumstances, which is why it’s important to keep the sprouts dry between washes.

Can moldy seeds grow?

Those seeds will not germinate if they contain mildew. However, if the damage is limited to the seedcoat or shell, the embryo, seed, or gymnosperm’s heart may still be intact.


As long as the mold hasn’t done any serious damage to your seedlings, it’s a simple operation to remove it from the seedlings.

Remember that in addition to taking quick action, it is equally important to change your planting procedures in order to prevent the molds from forming. In addition to saving you time and aggravation, mold removal can also be avoided.