How to Clean and Sanitize Microgreens Trays with Tips and Tricks from On The Grow®, LLC
Updated: Jan 3
You know How To Grow Microgreens, but you’re unsure of How To Properly Clean & Sanitize your trays now that they’ve been harvested…. Well luckily, On The Grow® is here to help answer this question! Knowing How to Clean & Sanitize trays is just as important as knowing how to grow the crops, because it is vital to creating a business and providing your costumers with safe product… Plus, it can help prevent you from running into pathogen issues like “Dampening Off”, which can wipe out an entire tray quickly and is frustrating to both Home Growers and Commercial Growers.
The very first step is to always clean off any debris left over after you’ve harvested, such as grow medium residue or microgreens that are still stuck. Then you will follow that up with sanitizing the trays and lastly allowing them to dry before your next use. It sounds simple, but this can be very time consuming if you haven't figured out some good methods that work efficiently for you. Which is why we wanted to share some of the methods that we've tried and hopefully it will make your next experience easier when its time to Clean & Sanitize your trays!
As a home grower, one option you have is to use your Kitchen Sink and do what we call the “Rinse, Scrub, Rinse” method, where you simply rise the trays off with tap water, then take a small Scrubbing brush and scrub off anything that is stuck to the tray, and then just give it another rise after scrubbing to ensure that everything is off. Make sure you have a strainer in your sink to catch any debris from the trays... Then you can either Spray the tray with a sanitizing agent like Bleach, Vinegar or Food Grade Hydrogen Peroxide that’s been mixed at the right portions with water as stated by your Local Health Department. If you have a dishwasher, they usually have a “Sanitize” option on it, which uses super high heat humidity to sanitize your trays. Keep in mind that the high heat may warp your trays since they are plastic. These are great options if your someone who really is not growing too many trays of Microgreens at a time.
Say you are a Home Grower, who does find themselves with a stack of dirty Microgreen trays and you have some space outdoors… Here is a fast option that may work for you! The Rise, Scrub, Rise, then Set in the sun to UV Sterilize method – but remember that this is meant more for people who are home growers and are growing produce for themselves because in a commercial setting this method could cause you to get a health code violation since UV sterilization is probably not an approved way to sterilize.
If you are on the commercial side of growing and find yourself with stacks of trays that need to be washed and sanitized, then these next methods will be better for you!
Rise, Scrub, Rise, Spray with Sanitizing Agent then allow to Air Dry – The great thing about this method is you won’t take up as much space since you won’t need a bunch of reservoirs like the following methods, but the Downside is you’ll find yourself getting wrist and hand cramps from the Spray Bottle over time, which can be painful and linger for a few days.
Rise, Scrub, Rise, Dunk in Sanitizing Agent For up to 10mins, then allow to Air Dry – This method is much faster and less hard on your hands then the previous method. This will require you to have a reservoir of water with Bleach or another sanitizing agent added. As for the ratio of Bleach to Water most people say the PPM of bleach added should be no higher than 200, otherwise it becomes toxic. The best thing you can do is contact your local Health Department to find out what your area's requirements and restrictions are when it comes to Sanitation for items that come in contact with food.
Dunk Multiple Trays in a Clean Reservoir together and Scrub all to remove Debris, then finish off with a Dunk in a Sterilizing reservoir together - This is faster than the previous two methods but comes with the downside of debris build up on first reservoir… it may be better to either spray rise the trays before the first reservoir or add in a 3rd reservoir. This way you can dunk in the first reservoir to get the main debris off, then dunk in the Second reservoir to get the left over Debris off and finish with the Sterilizing dunk last before air-drying.
Then our final method that we have found to be the absolute fastest of them all and our favorite is: First, you lay out however many trays you can fit on a plastic mat or on a clean area of concrete. Then you take a power washer and power wash off all the debris from the trays remembering to rotate them so you can get both sides. Lastly, you finish them off with a method of Sterilizing that best fits you and your local areas codes such as Dunk Sterilizing, UV Sterilization, Hot Steam or Spray Sterilizing.
We’ve found that the power-washing method works most efficiently with two people, one person sprays the trays while the other person can follow and flip them over so both sides get cleaned. Then the second helper can take the tray’s to be sterilized as you replace the clean trays with dirty trays for the person who is power washing. Keep in mind though do NOT use power-washing soap in your power washer, since most soaps sold for power-washing are NOT food safe and can leech some nasty chemicals into your greens. It is preferable to buy a power-washer and use ONLY for cleaning microgreens trays.
That’s it for Cleaning and Sanitizing methods we suggest, keep in mind you can mix and match methods with others until you find a way that works best for you!
As for how much and what type of Sanitizing agents you should be using, the absolute best thing you can do is contact your Local Health Department and ask them what their Sanitation Guidelines are because the amount of Sanitizing Agents that you can legally use is different in every county, state and region. Along with what type of Sanitizers are approved for the use of food, some places may require that you use bleach and others may just say that it must be an EPA approved product. Remember to do your own research so that way you can keep your business running smoothly and legally!
If this Article was hard to understand, and you need some visual reference for each method, then be sure to check out our YouTube video on Microgreens Tray Sanitation by clicking this link (here)
Here are a few reference links that we were able to find (keep in mind that some of the information is for certain States and may not apply to yours)
Also, here's a link to a list that has a few Green Options for Disinfectants & Fungicides
Lastly, if you find out your Local Requirements and need to measure your PPM (Parts Per Million) of your water to Sanitizing agent, Here is a Link to a PPM Pen that helps with this.
Want to learn EVERYTHING we learned from all our years of growing and experimenting with microgreens? Or maybe even learn some new recipes to use your Microgreens in?? Then check out our Books below!