How to PREVENT Microgreens MOLD (Problem SOLVED)

In my previous post I discussed the actual reasons why mold forms in your microgreens, but I never really talked about any of the solutions. By the end you will know the exact methods I use here in my farm to prevent mold from ever forming in the first place.

I've been growing microgreens commercially for years and have dealt with my fair share of mold, especially in the beginning when I first started. I’ve lost plenty of trays due to damping off, mold, and fungus problems. But I've dialed in my business procedures in a way that reduces the chance of mold in the first place. I don't sanitize my microgreens seeds, and mold never really forms in the first place, the ideal scenario, so I'm excited to share with you right now how to prevent mold from ever forming in your microgreens trays.

There's actually no way to eliminate mold spores because they're floating in the air around us… We're actually breathing them in every single day! Mold only causes problems when it replicates and is allowed to thrive, so the idea here is to limit and control the environmental factors that would cause the mold from forming in the first place.

The first step in preventing mold growth is keeping your equipment clean. Always sanitize your trays after each use and sanitize your equipment on a schedule to prevent the buildup of mold growth. When deciding where to initially set up your grow room, consider the past conditions of that space. If the space isn't clean or already has an excess buildup of mold spores, chances are this will cause problems. If the space is naturally hot, humid, and lacking fresh air, you might not want to grow there.

Controlling your environment is crucial when growing high quality greens and preventing mold growth. Use a dehumidifier to keep the humidity down, preferably between 50 and 60%. Make sure to have proper heating and air conditioning, this way you can control the temperature. I never let my farm get above 76 degrees Fahrenheit.

The most important environmental factor in my opinion is air flow. Even if your temperature and humidity happens to rise, air flow will keep those spores moving so they can't settle and proliferate. Keeping the air moving in your farm, whether you have big fans that move it through the whole farm or you have small fans that you have mounted to your microgreens racks, this will be a huge help in preventing mold growth.

Another way to encourage air flow without fans is to use shallow microgreens trays instead of the deep ones. This will position the base of the plants higher, closer to the top of the tray which will encourage air flow across the base of the plants where microgreens mold problems typically arise.

Your process of growing microgreens is also very important. Dialing in your watering is probably the most critical skill and process to develop when growing microgreens because overwatering will lead to excess moisture, causing mold and damping off. Overwatering is probably one of most common problems that new microgreens growers face when it comes to mold because this skill takes time to develop.

Dialing in seed density also plays a very important role here because too high of a seed density will trap moisture beneath the plant’s canopy within the microclimate and will also prevent airflow. Make sure to experiment with your seed densities so that you can find the ideal amount of seeds to use for your needs.

Also, if your seeds don't germinate properly, this is going to cause problems because the purpose of mold is to break down dead plant matter. Make sure to use high quality seeds meant for growing microgreens that have high germination rates and also make sure to have proper germination procedures in place.

Lastly, let me mention this specific tip that actually solved my problem with wheatgrass mold: Seeds generate heat as they grow, so even if the temperature is 70 degrees in your grow room, the seeds/plants could be reaching temperatures in the 80s while they are stacked and germinating. This, along with the necessity for moisture during germination, can definitely cause mold problems. My advice to you is to get your trays out of germination as soon as possible! The second I know that my seeds are rooted into my growing medium, I remove them from germination and put them under lights. This way they have less time in the germination phase where there is high humidity, high heat, and no air flow.

Now you have specific tactics you can use to prevent mold from forming in your microgreens, but what if you have other questions? Join my Microgreens Support Group on Facebook, that way you can get the help you need from myself and other growers.

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