Mold grows easily in warm and moist environment. However, you can control contamination with mold spores and spreading among plants in greenhouse. The most common types of mold that grow on plants include gray mold, powdery mildew and black sooty mold.
So, how do you get rid of mold in greenhouse?
The most effective way to get rid of mold in greenhouse is to prevent it from spreading. Follow the 6 easy steps below when setting up a greenhouse. However, if the mold is already growing on a surface, to get rid of mold in greenhouse you can use any of these two ways:
Solution 1 – pour vinegar into a spray bottle and apply it to the area affected by mold. Leave the vinegar on for a couple of minutes and wipe it off with a clean cloth.
Solution 2 – use an organic fungicide like a concentrated hydrogen peroxide (H2O2) solution. Mix one teaspoon of hydrogen peroxide with one cup of water. Dip in the cloth and wipe on area affected by mold. Leave the mixture on for at least 10 minutes, scrub the surface to remove mold and stains. Wipe down the area with a clean cloth.
How do you prevent mold in a greenhouse?
#1 – Maintain the proper temperature in a greenhouse
Greenhouse mold grows best in warm environment. However, if you set up your greenhouse facing south it will soak up direct sunlight early in the morning. It will help to dry the morning dew rapidly.
Although it helps to reduce the mold development because of the buildups of moisture being trapped, this trapped heat will create a humid and most environment without prompt ventilation.
You need to balance the temperature and humidity levels. Start by getting a greenhouse thermometer and hygrometer to monitor the temperature and humidity levels throughout the day. If required, get a greenhouse heater or follow 10 easy steps to heating a greenhouse without electricity.
#2 – Control humidity levels
There is a high chance of mold to take over when the humidity is high – over 85%. Keep in mind what you are growing but I would advise to aim for humidity level between 30%-50%. You can reduce humidity by improving ventilation and not overcrowding your plants.
Winter is especially tricky when it comes to humidity. When the temperature outside greenhouse goes down it cools the greenhouse panels while the warm air within the structure causes condensation. The greater the difference between the outside and inside, the more water condensates on the various parts of the structure.
#3 – Allow sufficient air flow in a greenhouse
Air circulation is a key to prevent mold from growing. When the airflow is poor, humidity levels increase which stimulates spores to spread. A natural airflow is created with the wind and circulation.
However, if you need to increase the airflow in a greenhouse you can use a fan. Install it in the front or back of the greenhouse to draw the warm air through a greenhouse and then blow it outside.
#4 – Keep excess water to a minimum
Excess moisture provokes mold development. Don’t overwater your plants and install a pump or a drainage system. Think about an appropriate watering system for your greenhouse. For example, drip irrigation helps to keep the leaves dry.
Make sure to remove the standing water from the plant foliage, soil, greenhouse frame and glazing panels as well as from other surfaces inside of the greenhouse.
Also, when watering your plants don’t leave the pools of water on the trays and floor. It is very important for the excess water to be drained when you are watering plants. If the water soaks up into the wooden greenhouse frame, black mold can form.
#5 – Avoid overcrowding
Ensure that there is an adequate space between plants. Packed plants create perfect conditions for growth and spread of mold. There is a poor air flow between densely packed plants which leads to higher humidity levels.
Moreover, it is harder to treat overcrowded plants affected by mold. When spraying or dusting the solution it does not penetrate or cover the dense foliage effectively. To avoid it you need to start thinning vegetable crops.
Thin plants in stages bearing in mind the end size of a healthy mature plant. You can thin plants by pulling or snipping off plant leaves and stems. Depending on what you are growing, I would recommend to keep plants 2-4 inches apart from each other.
#6 – Pay attention to a hygiene in greenhouse
Good hygiene helps to prevent plants from the contamination with mold spores. Each time when you enter a greenhouse you are most likely to bring something with you. If on a way to a greenhouse you walk across a lawn, you pick up mold and transfer it into greenhouse.
Remove the yellow and dead leaves, dying buds and flowers as soon as possible. Don’t leave dead plant material on the soil. Throw away any dropped fruits right away as they can start to develop mold. The fungus is in the ground. If you noticed leaves infected with powdery mildew, don’t panic and remove them.
Make sure to have a good cleaning routine in place. I would recommend cleaning the whole greenhouse with vinegar solution at least once a year. Also, don’t forget to clean all the tools and staging with vinegar too.
How do you treat gray mold in greenhouse?
Gray mold is caused by a fungus Botrytis cinerea and is the most common type of fungal infection in greenhouses. It affects many plants and is mostly prominent in herbaceous ornamentals. Also, it is a popular disease of soft fruit including gooseberries, strawberries and grapes.
To treat gray mold in a greenhouse use a combination of fungicides with different mode of actions and biological control agents like Bacillus subtilis, Streptomyces lydicus, Streptomyces griscoviridis and Trichoderma harzianum.
Botrytis is resistant to certain chemicals so using one chemical or a group of chemicals with the same killing properties won’t work. To treat gray mold use Copper Fungicide at the start of flowering, then apply BiotaMax soil probiotic around the base of the plants for 2 weeks.
Why is there mold growing on greenhouse soil?
Mold is growing on greenhouse soil because of the overwatering, poor drainage or contaminated potting soil. Most of the time the white stuff what you see on the soil is white fluffy fungus known as saprophytic fungus which does not damage plants.
To treat mold on greenhouse soil you need to remove mold from the surface. If the soil is soggy, consider changing the watering pattern or having drainage system in place.
Also, a very common reason why you get mold in seed soil is that the potting soil is contaminated. Remember that good potting soil lasts for 1 or 2 years max and you need to seal it properly after each use.
Why is the top of my greenhouse soil turning green?
The green top of the soil in greenhouse indicates that you are overwatering the soil and green stuff is blue-green and green algae. Although algae is harmless to plants, it acts as a growth medium for fungus which damages plant roots.
To get rid of green algae in soil you need to allow the soil to dry between waterings and increase the air flow in greenhouse. Consider to improve watering or start using high porosity soil instead as it will dry out faster.
