How To Clean / Sanitize Microgreens Trays (Fast & Simple)

One of the biggest pain points I hear about when it comes to doing farm chores and farm tasks is sanitizing trays. I've been able to keep this process really quick, simple, and efficient. When I first started my microgreens business, there really weren't that many trays to sanitize because I was operating at a small scale. But after about a year, I was going through a lot of trays each week, and I had to figure out a good way of getting them sanitized between each use. Today, I'm producing well over 100 trays per week, and I have no problem sanitizing them, so I'm happy to share my process with you.

Sanitizing trays is very important because these microgreens crops are grown so dense and so close together, it creates an environment that's prone to mold growth and fungus that can actually ruin your whole crop. Additionally, you want to be keeping your farm equipment clean and sanitized, not only for the wellbeing of your crops, but for the safety of your customers as well. By sanitizing your trays and equipment frequently, you're taking proactive measures to reduce the risks of not only fungus and mold growth, but also potential harmful pathogens like E. coli and Salmonella that might've snuck into your farm. Sanitizing trays properly is always a good idea.

With this being said, I do see some farmers going a little bit overkill with the cleaning and sanitizing of their microgreens trays, and they're creating inefficient processes that don’t necessarily work as you scale your business. Scrubbing the trays, bringing them outside, and hosing them down might not be necessary for keeping your farm safe and operational. 

What I do is really quite simple—I fill up a 2-liter pump spray bottle with 20 milliliters of a product called ZeroTol and the rest with water. This creates a dilution of the ZeroTol, which is a hydrogen peroxide that is food grade and OMRI-listed for Certified Organic Farming. It’s important to be careful in making this mixture because ZeroTol comes in a highly-concentrated form and is actually a caustic chemical. If you get your hands on this in it’s concentrated form, you’re going to get a chemical burn. Be sure to wear gloves whenever you’re using it.

After the hydrogen peroxide is diluted, I move to my super rack, which I put red tape on, to label it as my designated dirty super rack. After I dump the trays out into the big toter bins, they go onto the dirty super rack because the toters then come out of my farm to get dumped at a compost site. Because they get removed from my farm, I label them as unsanitary. So, if the tray is touching that toter as we're dumping the tray out, there’s potential for it to become contaminated, and I don't want to risk anything. 

Because I use these super racks for a lot of different things, including harvesting and moving trays around out of germination and under the lights, I want to keep them especially clean. Having a designated dirty rack makes sanitation easy because right after dumping into the toters, I load the trays right onto it, and once it gets a decent amount of trays stacked on it, it’s time to sanitize the trays. 

For sanitizing, I move the dirty super rack close to a clean super rack, and I take the trays off one by one. Then, I spray the trays down with the spray bottle of the diluted ZeroTol solution. I spray down both the top of the tray and the bottom of the tray (i.e., a tray set). 

Is this the best and the most thorough way to sanitize your microgreens trays? No, but when you're running a business, you have to keep your systems and your processes efficient. I’ve found that by using this process, it's kept fungus and mold from being a problem. And all of the important parts of that tray are being sanitized. I think this is a process that's simple, yet thorough enough, where it gets the job done and works for the farm and running a successful and profitable farm operation.

Ideally, you would want to be scrubbing down your trays with a scrubber and maybe a little bit of detergent to clean the tray before sanitizing. But in my opinion, I think it's a little overkill. If there's a little bit of soil stuck to one tray, it will get combined with the next use of that tray. And on goes the cycle of life.

When I think about outdoor farming, that’s way more potentially dangerous than indoor farming. There's a lot more variables outside, and it's not it’s necessary to sanitize the ground or anything like that. Again, I think this process is about finding a balance.

If you were super concerned, maybe you could sanitize the top and the bottom like I do. And then once a month, or twice a year, or once a quarter, you do a really thorough scrubbing of the trays by themselves (both the top and the bottom). This seems like a great idea and a great process to me. If I wanted to improve my process even further, I would fill up a big sink with diluted sanitizing solution, and I would place a big stack of trays in the sink. This allows for both a thorough soak of sanitation and a faster process, without having to spray each tray, though this method goes by relatively quick and has not hindered my efficiency in my farm.

Now you’ve learned how to properly sanitize trays, but what if you have other questions about a microgreens farm operation? I’d love to have you in my Microgreens Support Group on Facebook, where thousands of farmers from all around the world are connecting.