Seasons, Cycles, and Worms: A Less Obvious Fall Science Unit

Fall is my favorite season. Gorgeous temperatures (usually), gorgeous foliage (almost always), crunchy leaves underfoot (I don’t have to rake them), cozy sweaters, the beginning of hot chocolate season, and pumpkin everything! There are a gazillion great fall lesson compilations out there, like here, and here, and here (especially love the one at that last link about graphing the colors of leaves – except I’d just tape the leaves themselves to the graph rather than coloring in a representation –  more concrete that way, and more creative looking).

Most of these lessons involve the changing leaf colors, apples, pumpkins, temperature changes, etc., and they’re great. I’d like to take a less-explored aspect of fall – the decomposition cycle.

Stay with me here. The falling leaves of autumn are great for stomping, raking, rubbing, stamping, making into wreaths, and all manner of other activities. But when we’re done with them, what happens to them? What happens to the ones we leave on the ground? Are they still there in the spring? Well, some of them are, but many more of them decompose over the winter. Plants need healthy soil to grow, and winter is the time when soil rests and rejuvenates, and the dying plant matter of fall is what feeds the soil for the plants of next year. Think of winter as spa season for the dirt, and all those leaves and apple peelings are there to moisturize and replenish.

You can watch and track this process happening in your classroom. I’ve done it, it’s not as difficult as you might think, and it doesn’t have to smell at all. You just need worms to help you.

Vermicomposting

Yes, worms. Vermicompost is composting with worms, and it’s cleaner than you think. I’ve done it in classrooms and in a NYC apartment. It doesn’t smell unless you’re doing it wrong. You may find the idea of small wriggly worms unpleasant, but kids LOVE this. You’ll have a few who don’t want to touch them, but most will go for it, and if you do this project in pairs or groups, as I did, the daintier children can watch without having to be too uncomfortable.

There’s even a picture book that makes the introduction a little more friendly, Diary of a Worm by Doreen Cronin. Not directly about vermicomposting, but includes a lot of basic info about our wiggly friends.

A few basics. Worms need:

Darkness
Moisture
Brown matter (dead leaves, paper – this is their fiber)
Green matter (veggie scraps – this is their dessert)
Warmth (but not too much, they can dry out and die if it’s too hot)

You can buy worms at a number of places. I’ve always gotten mine from Uncle Jim’s Worm Farm (yes, that’s really a thing), where you can buy 500 Red Crawlers for about $16, or 1,000 for $20. He also keeps a helpful FAQ page that I’ve consulted more than once.

You can also buy special worm kits that make vermicomposting that much more straightforward, but they’re really not necessary. Any old storage bin will work, and created worm composting bins for an entire 2nd grade out of take-out containers donated from my local grocery store. You could use old hummus containers too, especially the family size ones would work well.

For a really good guide on creating one big class bin, look here.

The big class bin is more traditional worm composting, and probably the most efficient option if you want to keep the composting experiment going for the year (you could use the compost in the spring to start seeds for your Mother’s Day projects and bring the plant cycle conversation full circle). Just make “checking the compost” a classroom job and you can mostly ignore it. The only downside is that it’s harder for the whole class to watch the process in detail.

Which is why I did individual composters when I did it in classrooms two years ago. We weren’t extending it for a year, and my big priority was making sure all the students had a chance to see the decomposition in action. So here’s how we did it. Start with a small plastic container with a lid. This is one of the takeout containers we used in my classes, lid not shown.

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Make sure you poke some holes so the worms can breathe. Yes, worms need air too. Don’t worry, they have zero interest in escaping. It helps if you have an old-fashioned paper spike.

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Worms like the dark, which is why you normally raise them in opaque containers. But we want students to be able to watch them, so I used clear containers, and mitigated the sunshine problem by filling the container with dirt:

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This is regular potting soil. It’s actually a little nutrient-rich for worms, so they may take longer to get around to eating your veggie scraps. If you’re using opaque containers, you don’t even have to start with dirt, you can just fill the container with moistened (not drenched) strips of newspaper for bedding. I was afraid newspaper bedding wouldn’t give the worms enough darkness, hence the potting soil.

Note on moisture: Worms need a moist habitat. Too dry, and they dry out (they’re 90% water) and die. Too wet, and they drown. So make sure your bedding, whether it’s leaves, newspaper, or potting soil, is a little damp to the touch but not soaked. Keep a little spray bottle near the worm area so that if any containers get dry, they can be spritzed until they’re the right consistency.

After creating a worm-friendly habitat, add some worms! If you don’t want to touch them, you can just scoop them with your dirt cup, just make sure each container has a few. I’ve seen some websites recommend that you add your veggie scraps first and let them sit for a couple days, but you don’t have to. The worms might just ignore them for the first few days until they break down a little. So, after adding your worms, add food:

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Fallen leaves are fiber for worms. Very healthy. Make sure at least half the food you add is fallen leaves or moistened newspaper so your wigglies can keep their cholesterol down.
Smaller pieces are easier for the worms to tackle.
Smaller pieces are easier for the worms to tackle.
Don't forget your veggie scraps! These are like dessert for your worms. It's okay to spoil them a little, but if you give them too much, it can mess with the acidity and smell bad. These are brussel sprout leaves.
Don’t forget your veggie scraps! These are like dessert for your worms. It’s okay to spoil them a little, but if you give them too much, it can mess with the acidity and smell bad. These are brussel sprout leaves.

Final notes on keeping the worms: If possible, keep the containers in a warm (not hot), dark place. Like a closet, as long as your closet isn’t too close or too far from the window or heater. Take them out sometimes to check on them and note their progress, but for the most part, they do best when you leave them alone. After you add some veggie scraps at the beginning, leave the worms alone until the scraps are gone. If you add too many too fast, the system will get backed up and start to smell. Also, some foods are not easy for worms to eat and will start to smell before the worms can finish them, so avoid:

Meats
Dairy
Anything oily
Cooked food (tends to have oils and other additives that can be problematic)
Onions
Garlic
Citrus (too acidic)

Things that are great to add:

Raw veggie scraps – peelings, cores, the ends you chopped off, etc. Smaller pieces are better.
Newspaper (moistened)
Dead leaves (take a nature walk and bring back worm food!)
Eggshells (grind them up first)

And that’s about it! As noted above, if you keep them around long enough, you can use the worm castings (read: worm poo, read: nutritious dirt) for your spring planting projects and bring the unit around full circle. When you’re finished with your worm experiment, you can pass them off to anyone with a garden, or release them into any garden bed and they’ll make themselves comfortably at home.

Arts Integration

I usually consider this project hands-on enough to already count as “arts-integrated” even though there’s technically no art involved, but if you really want to bring it up a notch, you can make a construction paper mural of the decomposition cycle. Have students cut or tear out long strips of brown construction paper – this is a GREAT way to use up all those brown pieces they never want – and lay them out horizontally to make the dirt. Use brown strips of a different brown color to make a tree trunk with some branches and roots. Have the kiddos cut out a lot of leaves, both green to go on the tree and red/yellow to fall to the ground. Last, have them cut out some long red worm shapes which you can scatter across the dirt. They can write on notecards describing what happens in each part of the cycle.

Leaves fall in autumn -> They become worm food -> They are pooped out as nutritious dirt -> They feed the tree -> Which creates new leaves -> Which fall in autumn to continue the cycle.

Have each student keep a diary of the process, and you have a bulletin board. Ta-DA!

What do you think? Would you try this? Have you tried it? What worked? What would you do differently?


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