How To Keep Plants In Greenhouse From Growing Mold

Addressing the worry of how to keep plants in greenhouse from growing mold, manage the humidity, ventilation and circulation, and spacing and cleanliness indoors. We already know how worrisome it is to see mushrooms growing in the greenhouse, but what more if what’s growing indoors is a type of fungi that’s detrimental to plant health. Mold infestation in the greenhouse affects crops’ production, but the good news is it’s preventable with simple management practices.

When one sees mold growing in the greenhouse, it can pertain to different types of fungal diseases. White mold and gray mold are equally concerning to see indoors, but both also have the same management practices to prevent them from growing. The three methods below will keep your greenhouse healthy and mold-free.

How To Keep Plants In Greenhouse From Growing Mold

Guide On How To Keep Plants In Greenhouse From Growing Mold


Humidity control

When we think of mold and fungal growth, our minds automatically go towards the greenhouse humidity level. One of the most common fungal diseases, gray mold, or Botrytis blight, is manageable with proper humidity control. And if you think about it, controlling the indoor humidity will cost you way less than the loss you’ll experience from fungal diseases.

So how does one manage the humidity in the greenhouse? The University of Massachusetts Amherst recommends proper ventilation and airflow. This article will discuss these two practices in greater detail later on. 

Additionally, you can also use a dehumidifier to decrease the indoor humidity to prevent mold germination. Remember that if the greenhouse’s relative humidity goes over 85%, in addition to poor air circulation, warm temperatures and standing water will inevitably lead to the growth of mold. Therefore, ensure that the humidity level indoors should only be around 50 to 60%. 

This way, the plants still get their requirement, but you’ll also not encourage mold growth. 


Proper ventilation and circulation

As mentioned earlier, proper ventilation and circulation are the keys to preventing mold growth. You do this by using the vents and adding fans to the greenhouse. If you live in a humid area, a dehumidifier will also help maintain the humidity level in the greenhouse, but incorporating these two practices will be optimal. 

What ventilation and air circulation do for the humidity is to ensure that potentially moldy air goes out and fresh air comes in the greenhouse. Additionally, ventilation helps regulate the temperature to prevent the growth of mold. You can start by opening the vents in the greenhouse, and then you can gauge if you’ll need to add fans later on. 


Proper spacing and cleanliness

Besides the greenhouse conditions, a significant factor for preventing mold growth is proper spacing and cleanliness. We know that hygiene plays a huge role in keeping grass from growing in the greenhouse, which is also applicable to mold prevention. Much like weeds, spores of fungi quickly spreads through direct contact, air, and water. 

Ensuring proper spacing will prevent infection among plants and, as a bonus, also helps with air circulation and drying time after watering. This is because standing water on the surfaces also supports the growth of mold. Additionally, since fungi spread via the air, an air purifier can kill spores that might be present indoors. 

Lastly, cleanliness and sanitation throughout the surfaces, walls, and floors will help prevent fungal infection. It also includes thinning plants, removing dirty water, clippings, and potting soil, and wiping the tools you use for gardening. Infected soil and plant material can also cause mold problems, so be diligent in everything you bring and use in the greenhouse. 


Common Fungi In Greenhouse

Different types of fungi can grow in the greenhouse. However, the common ones are gray mold, white mold, powdery mildew, and black sooty mold. Most greenhouse gardeners tend to see gray mold as the familiar one because it can infect almost any plant. 


How To Get Rid Of Mold In Greenhouse

If you already have an existing mold in the greenhouse, you don’t need to fret because you can still get rid of it, depending on the circumstances. For example, both gray and white mold is the most problematic because you have to remove the infected plants in the greenhouse and bury them to prevent spores from spreading. On the other hand, you’re in better luck if you’ll be tackling powdery mildew because you can remove the infected leaves, and you’re good. 

What about black sooty mold? Bugs like aphids cause this infection, and therefore, getting rid of bugs will solve this issue. Start removing ants as they support other bugs, and then use insecticidal soap to manage the insects and pests. 



Greenhouse gardening will only be productive and rewarding if you know how to prevent potential problems beforehand. One of the common issues that you must learn is how to keep plants in a greenhouse from growing mold. With proper management practices like managing the humidity, ventilation, and circulation, and ensuring the spacing and cleanliness indoors, you don’t have to fear fungal diseases. 

The common molds in the greenhouse are gray mold, white mold, powdery mildew, and black sooty mold. Each of them has different ways of removal, so it’s best to practice prevention instead. Overall, the practices you’ll do to prevent mold growth will benefit you, not just against fungal diseases. 

Your plants will also thrive, and you can avoid other greenhouse problems. It’ll be like hitting multiple birds with one stone. 


One comment

  1. I appreciate that you brought up how you can prevent your plants from developing harmful diseases like gray mold by ensuring that humidity the levels are adequate. My uncle is thinking about growing lettuce in a greenhouse that he recently purchased last year, but he wants to keep the humidity levels consistent since the weather tends to fluctuate in his area. Maybe he should find a way to manage the humidity in his greenhouse.

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How To Prevent Root Rot In Hydroponics: 3 Useful Tips

If you’re a newbie gardener who’s looking to find ways to hone your skills, you’d want to learn how to prevent root rot in hydroponics even before this problem affects your plants.

Hydroponics can be advantageous to crops in more ways than one. However, it also comes with risks of diseases, such as root rot, which can be destructive or even lethal to your plants.

Unfortunately, there are no effective methods to recover the wilted parts that were affected by the root rot once it hits your plants. The only thing you can do if you do not want this catastrophe to befall your crops is to prevent it before it happens. Read on to learn more about this subject.


What is Root Rot?

Root rot is a disease that attacks the plant roots and causes them to suffer decay. This usually happens when a lack of oxygen supply occurs in the substrate.

To give you an idea, think about plant roots that are submerged in water that only has a little oxygen in it. Over time, the plant suffocates and dies.

Aside from rot and decay, this disease also leads to the proliferation of fungi that are naturally present in the soil. These include Rhizoctonia, Alternaria, Pythium, Botrytis, Fusarium, or Phytophthora. As soon as fungi colonies start to grow, they tend to target the weakened roots and infect your precious plant babies.

Once the plant becomes infected, they won’t be able to take in what they need to grow – water, oxygen, and other nutrients. When this happens, it won’t be long before the plant dies.


What is Hydroponics?

In case you’re not aware, the term hydroponic is derived from a Latin word that means “working water”. To put it simply, hydroponics is an art that involves growing various types of plants without soil. If you’re like most people, the first thing that comes to mind when somebody talks about hydroponics would be a picture of plants with roots suspended into the water without using any type of growing medium.


Avoiding Root Rot in Hydroponic Systems

Detecting and identifying root rot can be tricky. When your plants get infected, their leaves and roots gradually wither until the whole crop itself dies from the lack of nutrients, which is a common symptom of many diseases.


What causes root rot in hydroponics?

One of the requirements in hydroponics systems is oxygen. Without it, your plants are basically on the road to death. On the other hand, lack of such is one of the major triggers for root rot, and it must be avoided at all costs.

Just like when planting in soil, you loosen up the ground so that your plants’ roots can have their required intake of oxygen. That is the case for crops grown in aqueous solutions as well. If they cannot breathe, they would not be able to grow.

Another agent for root rot is the temperature. The last thing you would want in your system are parasites that leech nutrients intended for your plants and infect the water during the process. In common terms, these fungi are called molds.

One of the best breeding grounds for these is warm and moist areas. For this reason, if the water temperature inside your reservoir is high, then you are susceptible to it. Something as minor as letting the solutions exposed to sunlight can already be a risk factor.


3 Useful Tips on How to prevent root rot in hydroponics

There is good news! Root rot in hydroponics can be prevented! Just follow these tips:

Tip#1: Use the right air pump

If you do not want root rot to affect your plants, you merely have to avoid its causes. If you need oxygen, keep the water bubbling by providing an air pump of appropriate size, and also give importance to proper ventilation in the room.


Tip #2: Maintain the temperature

The temperature should be maintained within the 70 to 80 degrees F range. Get rid of any materials that can make your system vulnerable to infections, and make sure not to disturb your crops while they are trying to grow.


Tip #3: Get rid of the rotten parts

However, if you failed in preventing the disease, then the rotten parts should be removed immediately. Cut them off as there is no chance of reviving them, and focus on the potential new growth instead. Fix your hydroponics system and eliminate the risks.


Why Give Greenhouse Gardening a Try?

Greenhouse gardening offers numerous benefits to greens aficionados who dare to take their gardening experience to the next level. Aside from acting as a shield against the effects of inclement weather, a mini, hobby, or semi-pro greenhouse can also serve as a protective layer that keeps harmful bugs and critters at bay.

What’s more, its enclosed structure allows you to control your plants’ growing conditions including the temperature, light, moisture, and ventilation of the greenhouse’s internal environment. With a controlled environment, you’ll be able to extend growing seasons and grow plants that aren’t native to your area.



No matter how well-informed you are about how to prevent root rot in hydroponics, you cannot completely eradicate the risks. Therefore, to avoid the worst-case scenario, you should be prepared to sacrifice the infected for the sake of others. While you’re at it, consider trying your hand at greenhouse gardening as well.


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