Carolina Biological OSE – April 2024


Forums / Elementary Science / Composting

Elementary Science


Author Post
Susan Rush Susan Rush 775 Points

I'm working on an assignment for class and wanted to look at composting for elementary students. Do you think an indoor composting bin for a year is feasible? Too smelly? I know you can do it with minimal smell and I like the idea of students watching how waste turns into something reusable.

Victoria Tomik Victoria Tomik 225 Points

Also, if you are able to make a compost pile outside, plant some rocks in it so students can later feel them and notice how hot they can get!!!

Kehau Samuelu DonnaLynn Samuelu 3485 Points

Hi Susan, I don't know how big of an indoor compost bin you were thinking but I think smell and small insects like gnats or ant might be your biggest challenges. In a second grade class, we have made a compost jar and only kept it for a month. The smell wasn't too bad but it was a distraction for some students. They would check on the jar every 20 minutes once ants an other tiny insects started to come around. We found that putting it in the sun helped the food to break down. We also found that if the food was shredded like any vegetable peels, it really did break down in a month. Good luck with your compost. Kehau Samuelu

Susan Rush Susan Rush 775 Points

Ah, that's a good point. Thanks for the input!

Maureen Stover Maureen Stover 41070 Points

Hi Susan,

What a great idea to teach your class about composting. I really like that you will be doing the project for an entire year so your students can really see how the composting process works. Have you though about building a compost bin outside? Maybe you could have students collect food scraps from lunch and snacks to add to your bin. You could could even have the kids plant a garden (maybe with vegetables that could be used in your school cafeteria or flowers to beautify your school?). Here is a link to a website that has several different compost bins you can build: Compost Bins. Best of luck with this project! Keep us posted on how everything goes!


Robyn Terry Robyn Terry 360 Points

We just started an outdoor classroom this past year. This info is extremely helpful!

Patty McGinnis Patricia McGinnis 25635 Points

Make sure you research the types of things that should go into the compost bin and not go into the compost bin. Things you want to avoid are fruit and meat products (fruit will attract fruit flies). Here's a link that may help you:

Don Dean Don Dean 200 Points

This is definitely do-able without smell - just make sure it gets plenty of air. I had success with a vermicomposting bin. You need to get the right type of worms and there is some maintenance, but it works. Don

Susanne Hokkanen Susanne Hokkanen 79520 Points

I have two worm bins - and my kids love taking care of them. There is little to no smell, and it could not be any easier. The kids bring vegetable peelings, coffee grinds, egg shells and newspaper to school, as needed. I have attached a small collection I have started on worms and composting to this post. I would highly recommend worm bins for composting. :-)

Worms Collection (6 items)
Cristina Kelesides Cristina Solis 1355 Points

An indoor composting bin is great! I limit the organic stuff to egg shells, orange peels, things that are more dry and limit the quantity that enters the bin. And as someone else mentioned - never meat, fish, etc. One of the jobs they'll love is misting the compost bin with a water bottle and another is stirring it with a wooden stick.

Kathy Renfrew Kathy Renfrew 37148 Points

So I just read this wonderful string of conversation about composting. I am wondering, what is the next step? Do you use the compost? Did you ever consider a "kitchen garden" where you would grow ingredients that your chef at school would later use in cooking for the whole school populations.

Victoria Tomik Victoria Tomik 225 Points

Yes! You can definitely use the compost.. It is better and cheaper than buying gardening dirt at Home Depot. Great for when you are starting a garden!

Jennifer Rahn Jennifer Rahn 67955 Points

I have had classroom and home worm composting for about 3 years. It is great to see the reaction of the kids to the worms initially, and then see how they become more curious over time.

There are some great hints at How Stuff Works and New Mexico State University There is also a great little book, Worms Eat My Garbage, which has been out for about 15 years, and still very good.

As far as constructing the bins, I used several small bins, about 8 inches deep, and 13x18 on the top. Large is not better, because you need air circulation. I drilled holes in plastic bins, and use a second lid underneath the bin. Be sure you use lots of good bedding with your worms too - we have found that shredded office paper works great, but it could be a wonderful experiment in your classroom.

I do not use any animal products, citrus, or onions in my bins, and limit the amount of bread, which tends to become moldy. Onions tend to develop an odor. You may develop fruit flies, which can be irritating, unless you plan to use them for experimentation! I use a couple of bottles containing vinegar, and a paper funnel to trap the little buggers.

I will do some digging around, because I have a bunch of lesson plans for the composting, as well as some interesting supporting materials. Just have to figure out which drive they are on!

Peggy Ashbrook Margaret Ashbrook 10953 Points

If you want to try a worm bin at a minimal level, take a look at this one, photo attached. In an empty box for commercially sold salad we put shredded newspaper, some salad (no dressing), water to dampen, and about 20 "red wigglers" (purchased from the refrigerator at a pet store). One preschool class kept it for about a month with daily checks to add drops of water or vegetable scraps as needed. The resultant compost was heavy on newspaper and used to plant a houseplant. I used a hot metal skewer to melt holes in the lid for ventilation before working with the children. I don’t know if such as small bin would be sustainable for a school year, Peggy


Jennifer Rahn Jennifer Rahn 67955 Points

Just an idea - how about the plastic boxes that are sold containing a poubd of spinach or lettuce. Because they are clear, you would probably need to paint it. Worms prefer a dark environment.

Peggy Ashbrook Margaret Ashbrook 10953 Points

Yes! Jennifer, that is exactly what I used. I didn't paint it and the worms stay under the bedding, at least during the day, I don't know about at night. I could set it into a slightly larger cardboard box--do you think this is necessary or better? Another question, what do you do with your bin over the summer? Peggy

Jennifer Rahn Jennifer Rahn 67955 Points

We use our bins all year round. A bin that size will fit under the kitchen sink. I have not used one that small, because we generate way more scraps than it would accommodate. I really should try it - there have been several participants at a couple of conferences where I presented that were interested in the smaller size. In my experience, the darker the box, the better. Even though they hide in the bedding, the worms will eat more and be more active in a dark environment. I have set dark bins outside over the summer, and found that the sunlight through the drilled holes seems to encourage the worms to burrow deeper. If you want to observe the worm trails, you might create a "worm farm" similar to an ant farm, using thin plexiglas fronts and cedar for the sides. Keep the farms in dark paper bags, and pull them out when we want to observe. The worms move surprisingly quickly. Another thing that surprised me is the noise that they worms make as they munch. Get the kids to listen carefully. Some of they kids report that the worms seem to really like bananas and melon rinds. Look for small, light-colored yellow cocoons containing the young.

Jill Tung-Loong Jill Tung-Loong 300 Points

Thanks for all of your posts. You've all shared great ways to start classroom compost. I'm sure my students will be intrigue and curious to see how compost is created and the uses of compost.

Susanne Hokkanen Susanne Hokkanen 79520 Points

I use storage tubs...I think the 10 gallon variety, and we drill holes in the top. My next mission will be to seperate the compost from the worms...the bins are getting full. :-) It was recommend that I set up a new feeding area - one side of the bin with fresh newspaper stips (moist) and food...and only feed the worms on the new side. The worms should migrate to the new area, leaving the compost for collecting. My students have been 100% responsible for the worms' care this year, and they love it!! I am considering a planting project with my students, maybe a plant for Mother's Day, using the compost our worms have created.

Rena Roybal Rena Roybal 1810 Points

I have personally had a vermicomposting bin at my home with red worms for the last 4 years. At our school, the 5th grade classes use this in their science curriculum and our Kindergarten teachers are (reluctantly!) going to start using these bins next year. Initially, my family was reluctant to start our bin for fear that it would smell but it has no smell at all. In fact, if it does have a smell it means that there is an imbalance in the system. I started out with an 8" pot and now have a 2' x 1 1/2' large bin that I harvest about 4 times a year. I use the "tea" and harvested dirt for my planting. The dirt is so rich that it can be mixed with regular potting soil. I used shredded bills and papers in addition to recycled newspapers in my bin. (Worms can even help with curbing identify theft in this way!) This is an excellent teaching tool for any grade level classroom from K-12 and covers many different areas including recycling, decomposers, life cycles, ecosystems and the list goes on and on. Here are a few resources that showcase a school that used it to create a pipeline vermicasting system and the company that helped them set it up: Yes, this is a large scale project but any classroom can start off with an 8" bin. And, teachers, don't be afraid to get dirty!

In the past, I've done vermicomposting with 2nd and 3rd graders in 8-12 inch bins. We would keep a log of what was put into the bin each time it was filled. After the end of each quarter, we would harvest the fertilizer, weigh it and bag it. We tracked the amount of what went in, the length of time it took to decompose, and the weight of the fertilizer harvested. The fertilizer is very rich and I'm sure when mixed with soil will be great for planting. The fertilizer is then given to those who were interested in having it for their plants. Had I planned beyond composting, I would've used used the fertilizer to pot plants to extend the science lesson. The students loved having the bin and participating in composting throughout the year. It gave them a sense of responsibility as they had fun gaining knowledge. During the summer, a student volunteer or the classroom teacher would bring the bin home until the school year starts again.

Peggy Ashbrook Margaret Ashbrook 10953 Points

They run a very impressive composting system!

Shawna Fischer Shawna Fischer 2300 Points

This post is inspiring me to try a worm bin! I might have to wait until next school year though. A few other teachers in my grade level use it all year long for inquiry learning. They weigh it at the beginning and as soil is created through the year. They have the students develop a hypothesis about which color paper the worms would "prefer" and then test it out. I think it is too late this year to start one but maybe I will borrow my coteacher's worm bin for a few lessons. The fruit flies seem a little discouraging though!

Caryn Meirs Caryn Meirs 26235 Points

This is such a great thread! I love my worm bin! We have some worms making the rounds to different classrooms - a 1st grade teacher reported that student journaling improved with the worms, and how students even incorporated the worms into their own writing pieces - giving them jobs and dialogue! It is interesting to look at the compost with hand lenses/microscopes to see the different states of material and look for the worm casings. I owe a long time ago Quaker teacher for this fantastic idea - she had her students do an entire marketing project about the compost - lots of research, writing and communication skills right?! They designed package labels and they actually sold it as a fundraiser toward the class garden project. Genius!

Jorge J. Zaldivar Jorge Zaldivar 3470 Points

Susan, How did this project go? Did you complete the year long process? I know it may be difficult because of the summer, regardless this initiative is definitely worth enacting. Catching up on this idea while helping me gather some great information. I am setting up a lesson on composting. I will be focusing on the following standard for my state. [b]Florida - SC.2.E.6.2 Describe how small pieces of rock and dead plant and animal parts can be the basis of soil and explain the process by which soil is formed. Excellent thread! [/b]

Catherine JeanPaul Catherine JeanPaul 805 Points

I think its great that students are being exposed to composting right in the classroom. It is an important way to recycle resources, something our future generations need to be well aware of. I think its important to consider what is going in the compost, and where it should be placed; Taking into consideration student allergies and seating charts. The students checking on it every "20 minutes" isn't inevitable with great classroom management. Having designated time to "make observations" and time to create the compost is a way to keep students on task and away from the bin or jar. I believe this exposure to methods of sustainability is absolutely uplifting for students as well as for teachers.

Steve Rich Steve Rich 928 Points

You can find composting lessons and related topics in both of my NSTA Press books Outdoor Science and Bringing Outdoor Science In. Search for them at the NSTA online book store.


Author Steve Rich's Website (External Website)

Victoria Tomik Victoria Tomik 225 Points

Hello! I would definitely not suggest having an indoor compost pile/system going on. However, you could do a mini worm bin! Worm bins can be done if you layer plastic containers if you punch holes in the bottom of each.

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