How to Sanitize Seed Trays

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If you’re using seed trays to start seeds indoors or if you’re transplanting your seedlings into larger containers, you’ll need to know how to sanitize seed trays to protect your new seedlings from diseases caused by fungi and mold.

how to sanitize seed trays disinfect clean diy

I may have jumped the gun and planted my seeds a little too early this year. I guess I just couldn’t wait to jump into gardening season again!

But that means I now have fifteen tomato plants that have outgrown their pots and need to be transplanted into larger containers.

I got onto a social media group for my local town and asked if anyone had any plastic pots I could use. I got a good response in a matter of hours and was able to gather enough pots to transplant all my tomato starts!

sanitize seed trays transplanting tomato plants rootbound root bound growing trays seedlings starts clean disinfect

Bonus!! One of the kind people who was giving me her extra seed trays and plastic pots happened to be moving soon. She starting giving me other items in her shed that she no longer wanted. I walked away with a huge roll of thick landscape fabric and a couple of self-watering planters in addition to what I went there for.

People are good! If you’re ever in need of things for your garden, it’s worth asking your local groups.

Watch Video: How to Sanitize Seed Trays

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Why Should I Sanitize Seed Trays?

In order to use containers that are dirty and/or have been used before, they need to be cleaned and sanitized. Cleaning is removing the visual dirt that you can see on the surface. Sanitizing is removing any harmful fungus or mold spores remaining on the seed trays so that your brand new little starts won’t become sick and die from anything that was in there from past plants.

Supplies Needed to Sanitize Seed Trays

plant containers seedlings starts seeds potting soil disinfect sanitize seed trays wash clean

Instructions for How to Sanitize Seed Trays

Step One: Remove Dirt

Shake as much dirt out of the trays as you can. I advise doing this outside! Then, rinse any extra loose dirt out of the seed trays.

Step Two: Clean Seed Trays

Add liquid dish soap to the seed trays, and use an old sponge or scrub brush to remove dirt that is caked onto the sides of the containers.

Rinse seed trays well. If you feel anymore dirt on the container, scrub it a second time, then rinse again

Remove the clean seed trays from the sink and spray down the sink before the next step.

diy how to sanitize seed trays seedlings seed pots starts disinfect spray bottle hydrogen peroxide

Step Three: Sanitize Seed Trays

Place the clean seed containers back into the sink.

Remove the lid from the hydrogen peroxide and add a spray nozzle. I removed the spray nozzle from a glass cleaner bottle — just be sure to rinse it thoroughly so the chemicals don’t mix.

Spray the hydrogen peroxide all over the surfaces of your containers. Let sit for 20 minutes.

Step Four: Rinse & Dry

Rinse containers with water and towel dry. If you will be planting right away, then don’t worry about getting the seed trays completely dry.

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  1. Fantastic info! I’m pretty sure I’ve killed a few plants by transplanting them into containers that may have had a fungi or mold from it’s previous occupant.

    1. Thanks, Tara! I’m glad you found this post helpful!

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