Can You Use Moldy Potting Soil? - Backyard Boss
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Can You Use Moldy Potting Soil?

Soil is essential for healthy plant growth. But, what if you notice mold growing in your plant’s soil? Is it dangerous or could it be beneficial to the plant? Learn everything you need to know and some tips on how to deal with moldy potting soil.

Can You Use Moldy Potting Soil and is it Bad For Your Plants?

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While it isn’t necessarily immediately harmful, it is a good idea to get rid of mold in your potting soil. It may fight with your plants for nutrition and it also gives out a very unpleasant smell that no one would like to have in their home or backyard.

However, it is important to first find out why your potting soil might be moldy before deciding on what to do about it. The most common type of mold you can see on your potting soil is white mold. It does best in humid conditions and is most commonly seen when there’s overwatering, bad drainage, or impure potting soil. Moreover, it could result from poor aeration or lack of sunlight. Another reason could be the usage of organic fertilizer.

What Will Happen if Your Soil is Moldy?

Mold on your potting soil isn’t always a bad thing. It will not damage the plant immediately but is a clear sign that your soil is lacking what it needs to flourish. White mold is called “the litter transformer”. This is due to its ability to consume decaying organic matter and make it into something helpful to the soil. However, this is not to say that you should take no action!

The mold will eventually affect your plants and they will start turning yellow, wilt, or will even die. Thankfully, there are a few easy ways to get rid of mold on your potting soil.

3 Tips on What to do About Moldy Potting Soil

While your first instinct may be to scrape the mold off, there are a few easier and more effective ways to remove it. However, ensure that you have gloves and a facemask at your disposal. Mold can be quite harmful to humans!

1. Sunlight

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Your first step should be putting the plants in a sunny and well-aerated place. If you’ve caught the mold early, then receiving enough air and sunlight should be enough to make it go away.

2. Repotting

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If putting your plants in a sunny and well-aerated place doesn’t do the job, you should try to take the plants out of the pot and remove the moldy soil, then replace it with a fresh one. Moreover, you will need to clean out the pot very well, to minimize the risk of mold returning.

3. Use a Fungicide

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If neither of the previous ways worked, you should find a fungicide. It will help get rid of any leftover mold. If you aren’t a fan of chemicals, though, and prefer a homemade mixture, you can mix potassium bicarbonate with water and use that. Cinnamon can also be an excellent fungicide.

If you are looking for an overall good fungicide, you should look at the Garden Safe Fungicide spray. It can be used on a wide range of plants and it can be used up to harvest day. It is a great choice for those of you who are into organic gardening.

If you are looking for a different option that is more budget-friendly, then you should look no further than the Bonide Sulfur Plant Fungicide Dust. It is effective against a lot of insects and diseases and you can use it on fruits, vegetables, and even ornamentals! Moreover, it is safe for animals.

Preventing Mold Growth

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Mold will never be completely gone because its spores are a component of soil, even though usually quite harmless. While heat, humidity, and lack of good aeration are a hazard to your plant, they can help mold spores thrive and become adult fungi. However, if you follow these steps, you will be on the right track to avoiding them:

1. Water in Moderation

Usually, mold growth in containers is caused by overwatering. Spores are more likely to do well in consistently humid conditions. This is why you should always make sure that the soil in the pot is dry before watering. To check if your plant needs water, stick your finger in the soil about one or two inches deep. Pull your finger out and if the soil feels dry, your plants need water and if it’s moist, check again in 24 hours.

2. Increase the Aeration

A stale environment will help mold thrive. This is why you should place your pots and containers in sunny and well-ventilated areas. If this is not possible, use a fan to help the aeration process.

Frequently Asked Questions

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1. Does moldy potting soil hurt plants?

No, mold in your potting soil won’t hurt your plants, but they indicate your plants are lacking the right environment to thrive. Maybe they’re over-watered, they lack proper drainage and air circulation, or they don’t receive the amount of sunlight they need to grow.

2. Can you use a bag of moldy potting soil?

Sometimes it may happen that the brand-new bag of potting soil you just purchased is moldy. The question is – can you use that soil? Yes and no. Yes, you can use the soil if you are transplanting, planting, or replenishing.  Mix it up well and massage the mold into the rest of the mix. Or, you can add fresh compost to the mix. Leaving the bag outside under direct sun for a couple of days is also a good way to ensure that it is suitable for use. No, don’t use it if you are seed-starting. The mold will compete with the plant for nutrients, which will lower its fighting chance and will most often result in its demise.

3. Why does potting soil in a sealed bag have mold?

If you keep your sealed potting soil bag in a dark, humid environment, it’s likely to attract mold. It’s a good idea to keep sealed potting bags in places where they receive some hours of direct sunlight to keep in dry inside out.

4. A large amount of my plant’s soil is moldy, can it be saved?

It’s best to repot your plant because there is likely something wrong with the soil it’s growing in. After repotting the plant, go back to the pot with moldy soil. Scrap out as much as you can and spread the remaining soil on a clean tarp under the sun. Let it “bake” for a few hours and then add an anti-fungal solution to it. If you don’t have one handy, sprinkle cinnamon or baking soda on the soil. Mix it thoroughly to ensure that the solution, cinnamon or baking soda is evenly distributed. You can continue to semi-bake it under the sun (keeping it in a place that doesn’t receive direct sunlight) to let it dry and aerate before using it again.

5. Is plant mold dangerous for humans?

Always remember to wear your gloves and a mask whenever you’re handling mold. People who’re sensitive to mold can develop allergic reactions soon after touching or inhaling mold spores. Symptoms include sneezing, runny nose, blood-shot eyes, and possibly some skin rash. People with serious mold allergies must never go near or touch mold without proper gear because it could cause shortness of breath.

In Summary

While the sight of mold in your pot or container can be upsetting and stressful, it does not necessarily mean that your plant is in grave danger yet. All you have to do is ensure that your plant has a lot of sunlight, good airflow, and is not over-watered.

However, if these factors are there, but the mold hasn’t disappeared, maybe a fungicide can help. If you can’t use cinnamon or baking soda, you have the Bonide Sulfur Plant Fungicide Dust as your budget-friendly and very effective option and the Garden Safe Fungicide Spray as your more versatile and slightly more pricey option.

Hopefully, this article has helped you deal with your moldy potting soil and has reassured you. If you have any questions, please leave a comment down below!

Happy Gardening!