Worms in Microgreens Trays?

Recently, Shaul G posted in our Worm Farming Alliance discussion group about a YouTuber who calls himself “Papa Blue Shirt”. This gentleman is big into growing microgreens and baby greens…with a twist.

He adds composting worms to all his grow trays!

Naturally, this caught my attention and I decided I had better check out some of his videos.

Here is one that shows his basic process for setting up new trays with worms:

For a full list of all his worms + greens related videos I recommend checking out the Papa Blue Shirt Worms in Microgreens Playlist.

I myself have dabbled with microgreens in the past, and I’ve certainly had lots of “volunteer” plants sprout up in active worm bins (eg. the crazy pumpkin sprouts I wrote about in my “Worm Bin Microgreens” post), but I’ve never purposely grown greens with worms in the mix.

Obviously, the soil mix used to grow greens is a far cry from the rich environment found in a typical worm composting system, so I naturally wonder where the worms will get their nutrition – and what sort of contribution they will actually make to the growth of the greens.

Papa Blue Shirt says they help to control mold growth in the trays, which seems reasonable – especially given their limited food options.

Whatever the case may be, I KNEW this was something I needed to test out for myself!

Luckily, I still had some nifty microgreens trays my friend Alan Yokiosha (Urbafresh) sent me a couple years ago. I also had a bag of potting mix + “pit moss” used for my last microgeens experiment.

I always have lots of old seed packets kicking around, and I figured it would be fun mix up some different greens – arugula, a mesclun mix, romaine lettuce, and kale

My trays are definitely smaller than the ones Papa Blue Shirt uses, and they have the added disadvantage of being transparent – so the worms will have a rather small zone in which to completely avoid the light. That said, I am starting with a lot fewer worms (than PBS puts in his trays) – and they are from my coffee tub system so they are already used to having limited space.

For the sake of providing the worms with a bit more nutrition I decided to add a small quantity of poultry feed pellets down in the very bottom of the tray. To keep things consistent I did the same in the no-worm tray as well.

My soil mix was fairly dry, so once I filled the trays most of the way with it I added quite a bit of (rain) water and let them to sit for a while.

Once I felt the soil had a decent moisture distribution I added 15 worms.
[Note: I just happened to snap a picture of two adults, but most of the worms are actually very small juveniles.]

Next, I added a bit more soil and a similar mix (and quantity) of seeds to both trays, before adding a cover layer of the soil mix and watering again thoroughly.

The trays will be sitting in a (DIY) styrofoam grow chamber that sits on top of my heating mat. I don’t have the best growlights but the white walls of the box should help a fair bit. Lights will be turned off at night, giving the worms the opportunity to roam around a bit more.

I’m pretty excited about this experiment. Always fun growing things, and I am really interested to see how the worms do in this type of environment! I honestly don’t predict any earth-shattering differences between the trays, but I guess we shall have to wait and see.

Stay tuned!

**Want Even More Fun With Worms? Sign Up for the RWC E-mail List Today!**
Previous Post

Worms in Microgreens Trays – Update

Next Post

World’s Smallest Bin – Coffee Tub System Update


    • David
    • September 24, 2021

    Traditionally growing microgreens can be a big problem with mold since you have to keep the growing medium so wet all the time. To combat that, growers use sterile potting mix and fans to keep the air circulating. I’m interested to see how things turn out by adding worms to the mix!

    • Bentley
    • September 24, 2021

    Hey David!
    Yeah I am especially interested given the fact that I added the pellets. I will not be surprised in the least if those end up causing issues in the no-worm tray. The big question is whether or not the worms can keep things “clean” in the other tray!

    • Michael Linley
    • October 21, 2021

    So the other benefits I see with using worms in the trays is better aeration and drainage due to worm tunnels everywhere. The worms will also be eating and leaving behind nutrient rich castings for the roots to take up into the microgreeens. Sometimes when I grow wheatgrass the roots eat up pretty much every last piece of soil so I am wondering what will happen to the worms if the soil gets eaten up by the roots! I have seen worms just wander into my outdoor wheatgrass trays so they don’t mind the environment but I use my own compost and sometimes it has unbroken down organic material in it so they are going for that I am sure plus they like the high moisture content. I also add azomite to my soil and sometimes compost tea.

    • Bentley
    • October 22, 2021

    Hey Michael – Red Worms aren’t really burrowers like various soil species but yeah they should definitely create some air spaces just via their movements in the substrate. What you mention about the roots taking up all the space is an excellent point – and this was in fact my major concern! Not sure if you are on the RWC email list, but as I recently shared, it turns out the worms did surprisingly well (after a month of living in the grow tray). I recovered all 15 worms and they seemed very healthy (all the small ones had grown quite a bit as well), even with their habitat completely overgrown with roots. Pretty cool (and surprising). 😎

    • Shaul Grantz
    • November 25, 2021

    According to the original source (Papa Blue Shirt), there is no mold issue, because the worms come up onto the surface at night and eat all the mold. Furthermore, he said that with the worms in the grow trays he was able to achieve more than 10 consecutive plantings without any additional fertilizer.

    • Shaul Grantz
    • November 25, 2021

    I wrote my comments before I saw the (above) article. Ah well…

Leave a Reply

Your email address will not be published.

Get Your Free Vermicomposting Guide!

* Join the Red Worm Composting E-Mail List Today *