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It’s a problem.

You’re growing plants in the planter box, and things were going great. But today you see some mushrooms have cropped up in the potting soil.

You don’t like how they look and want to get rid of them. But how to do that without harming your plants?

In this post, I’ll help you with 6 super tips to get rid of mushrooms in your planter box. I’ll also show you how to prevent mushrooms from growing. And why you should consider keeping the mushrooms in your planter box.

Let’s begin.

How to get rid of mushrooms in planter box?

1. Move the planter box under sunlight

Mushrooms prefer humid environments. Some will prefer cold locations while others may grow in humid conditions.

The easiest way to get rid of mushrooms is to move the planter box outdoors where there is bright sunlight.

The sunlight will dry the mushrooms and the potting soil where they tend to grow. And the mushrooms will die as a result.

It’s important that you don’t water the potting soil when you keep the planter box outside to give the best chance of killing mushrooms.

I asked fellow gardeners if they prefer to remove mushrooms from their potting soil. A majority 97.6% of them felt that mushrooms are harmless and they leave them alone.

2. Pull out the mushrooms by hand

This is also an easy method to get rid of mushrooms. You just pull them out of the potting soil and dispose them.

You need to be careful not to spread the spores when pulling the mushrooms out. Otherwise, the spores will get into the potting soil and you’ll have mushrooms growing in a few days.

I would suggest grabbing the cap and pulling that out first to prevent the spores in it from spreading. Then you can pull out the stalk from the potting soil.

Pull all parts of the mushroom out of the potting soil. You can take out the top 2-inches of the potting soil and dispose that as well to keep as many spores away as possible.

It’s best to put the mushrooms and potting soil in a ziplock or garbage bag and throw it away. Don’t put those in the compost pile as the spores can remain and the mushrooms grow back when the compost is used.

The best thing to do if you have mushrooms in your soil? Let them be! If they are bothering you visually, simply pluck them from the soil and toss them. You can put them in your compost pile. Or, if you’re worried about them spreading in your compost, toss them elsewhere in your yard to safely decompose. – Kate Moore, Mushroom Enthusiast, Remeday

3. Use organic fungicide to get rid of mushrooms

I would recommend using organic fungicide than a synthetic one to get rid of mushrooms. You will avoid damaging the plants and wildlife.

Some options that can work to get rid of mushrooms include soapy water, vinegar, sulfur, and baking soda.

Soap water

Mix 2 tablespoons of organic dish soap with 1 gallon of water in a container and mix it well. Dig small holes in the potting soil around mushrooms and pour this solution in them.

You can also spray the solution on the mushrooms. This will dry out the mushrooms and kill them.

Vinegar

Mix 1 part vinegar with 1 part water in a spray bottle and spray it on the mushrooms to kill them. You need to be really careful only to spray on the mushrooms as this can damage the plants as well.

Sulfur

You can dust sulfur powder on mushrooms because it works as a fungicide. The problem is sulfur can make your potting soil acidic.

You can use lime sulfur instead that balances out the acidic levels of the soil. The benefit of sulfur is it will keep some other diseases away from the soil as well.

Baking soda

Baking soda is another natural ingredient you can use to get rid of mushrooms. Mix 2 tablespoons with a gallon of water and spray it on the mushrooms.

Baking soda is alkaline, so be careful that you don’t use too much and change the pH level of your potting soil.

Neem oil

Neem oil is a natural fungicide that can get rid of several fungi, including mushrooms. Use organic, pure neem oil so there are no chemicals.

Mix 1 tablespoon neem oil and a tablespoon of dish soap with a gallon of water. Spray this solution on the mushrooms every few days.

organic neem oil
Organic neem oil I use on my plants

4. Clean up the potting soil

Mushrooms grow when the potting soil is moist and rich in nutrients. If you want to get rid of them, you need to get rid of some potting soil as well.

The first option to try is to remove the top 2-inches of the potting soil together with the mushrooms. If mushrooms are still growing, you’ll need to get rid of the entire potting soil. Collect the potting soil in a garbage bag, seal it, and throw it away.

Clean the planter box with a solution of 1 part bleach and 9 parts water. Scrub all the dirt away and let the bleach solution stay in the planter box for an hour. Then use clean water to rinse the solution off the planter box.

Use good, sterile potting soil in the planter box to ensure it does not introduce mushrooms spores.

5. Reduce watering the potting soil

Mushrooms love a humid environment that can occur in a planter box. You need to be careful with the watering.

Check the moisture in the potting soil before you water. Stick your finger 2 inches into the potting soil and check it.

You only need to water the plant if the finger comes out dry. Otherwise, there’s still sufficient moisture in the soil.

Another easy option is to use a moisture meter that is placed in the potting soil. It will tell you exactly how much moisture is there and if your plants need watering.

Once you reduce the moisture in the potting soil, the mushrooms will die off a well.

6. Increase alkaline levels in the potting soil

Mushrooms prefer acidic soil to grow well. So one option to get rid of them is to make your potting soil more alkaline.

This can affect your other plants that would also prefer acidic soil, so be careful and only use this for certain plants.

You can use organic material such as baking powder or sulfur to increase the alkaline levels in the soil. These materials also act as a natural fungicide to get rid of the mushrooms.

How to prevent mushrooms from growing in planter box?

1. Ensure the potting soil gets good sunlight

Make sure that your planter box is in a location that gets good sunlight. You want to avoid a humid environment that can encourage fungus like mushrooms.

Keep enough space between the plants in the planter box so there is no crowding and shaded spots. You can trim some of the foliage if this problem already exists.

If the planter box is in a shaded area, you can consider moving it to a better location that gets enough sunlight and wind to keep it dry.

2. Keep the potting soil clean and free from debris

Mushrooms like to grow in environments with decaying organic matter. So if your planter box contains fallen leaves, mulch, or fresh manure, mushrooms would use that as a growing medium.

I recommend keeping your planter box clean and remove any fallen leaves and branches. You can add those to your compost pile instead.

3. Use a good, sterile potting soil

This is one of the common issues that can cause mushrooms to grow. The potting soil could contain mushroom spores that start growing when put in a planter box.

Use potting soil that is sterile and purchased from a good source. This does not mean you won’t get mushrooms, but it would reduce the chances.

I would not suggest using garden soil in your planter box, as that can contain plenty of mushroom spores and even pests or diseases.

If you want to reuse potting soil or garden soil, I would recommend sterilizing it before use. You could bake the potting soil in an oven for an hour before use. So it would kill the spores, pests, and diseases in the soil.

Mushrooms are caused by spores and the breakdown of organic matter. One way to get rid of the mushrooms is to sterilize your soil.  This can be down by covering, or containing your potting soil and steaming it or baking it. This can harm good microorganisms or beneficial insects in the soil.  I would do this only if it was an extreme situation. – Stuart Mackenzie, Horticulturist and Expert at Trees.com

4. Prevent overwatering the potting soil

Mushrooms like potting soil that is moist and has plenty of decomposing organic matter. If you keep overwatering the soil, this becomes an ideal environment.

Preventing such overwatering will help keep mushrooms away from your planter box. You want your planter box to have sufficient drainage holes at the bottom.

Make sure those drainage holes are the right size and don’t get clogged because of the potting soil. You can line the planter box with plastic liner to help with this.

Check the potting soil before you water the plants. Stick your finger a couple of inches into the soil and test if it comes out dry. That’s when you can water the potting soil and not otherwise.

It’s best to water the potting soil in the morning so that the excess moisture will dry when the sun comes out and prevent a humid environment for the mushroom growth.

5. Turn the potting soil every week

You can prevent damp potting soil by turning it every week. This gives plenty of aeration to the soil in the planter box and the mushroom spores won’t be able to grow.

You can use a trowel, fork, chopsticks, or knife to turn the potting soil. This also helps with the drainage in the potting soil as it prevents clumps.

You can also add a slow-release fertilizer to the potting soil as you’re turning the potting soil. Typically, you add this every month to give a boost of nutrients to plants.

Should I remove mushrooms from my planter box?

I don’t recommend removing mushrooms from your planter box because they are useful for your plants. The mushrooms decompose organic matter and provide nutrients to the soil. The mushrooms will also decompose after some time and enrich the potting soil.

They don’t harm the plants as they grow on the nutrient medium in the soil, such as decomposing leaves, branches, or mulch.

However, there are a few reasons you might remove mushrooms from the planter box. Some of these mushrooms could be toxic, so consuming them could cause problems. This could be mild issues that cause a visit to a doctor or, in worst cases, result in hospitalization.

You don’t want your children or pets near such mushrooms growing in the planter box. So you can remove these mushrooms to be on the safe side.

The other reason to remove the mushrooms from your planter box is for aesthetics. Some people don’t like mushrooms and think they are gross. I, personally, don’t mind mushrooms and think they are beautiful. They add character to the planter box and your garden.

Mushrooms growing in your compost isn’t a bad thing. People get scared when they see fungi fruits appear, thinking that it’s poisonous and can make them ill, especially around vegetables and fruits. However, fungi and mushrooms in your soil are an indication that the soil is packed with life, and these fungi will continue to break down the organic matter into useable nutrients for the plants you are growing. The mushrooms in the potting soil also aid in water retention, which acts like a sponge, a reservoir if you like that your plants can tap into. – Tony O’Neill, Gardener, Simplify Gardening

Here are some of my favorite container gardening tools

Thank you for reading this post. I hope it helps you with your gardening needs. I’ve listed some tools below that can help you with container gardening. These are affiliate links so I’ll earn a commission if you use them.

Gardening Gloves – I find the Pine Tree Tools Bamboo Gardening Gloves really good for both men and women. It’s made from bamboo so helps absorb perspiration. They are also comfortable and fit very well.

Containers – You know picking the right container is crucial for your container gardening. I’ve written a detailed post on the best containers you can choose from. If you’re happy with a plastic container, you can check out the Bloem Saturn Planter.

Watering Can – This is a must-have tool when you’re growing plants in pots or grow bags. It helps to water the potting soil without splashing on the foliage. The Kensington Watering Can is stylish, strong, and can provide precision when watering potted plants.

TrowelGarden Guru Trowel is my favorite because it’s durable and comfortable to use. My gardening friends really love having a trowel because they use it for digging soil, mixing fertilizer, moving seeds, leveling out the soil, mixing compost or mulch, and also dividing tubers

Bypass Pruner – I really like the Corona Bypass Pruner because it’s durable and gives a clean cut that helps plants recover faster. If you’re looking for something cheap, get the Fiskars Bypass Pruner that is really good as well.

To see an extensive list of the best container gardening tools gardeners recommend, check out this resource that I made for you.