An easy way to go green in the classroom is to upcycle! Upcycling is the process of converting old or discarded materials into something useful. Here are some ideas for upcycling in your classroom!
Use paper towel/toilet paper rolls for a fun STEM activity, like building your own marble run.
The rolls are also great for all kinds of crafts!
Instead of buying containers from the store (hard to resist all those cute and colorful ones I know), try to use some that you already have to organize and store materials. We used this big container that our animal crackers came in to store our wooden building blocks, since the box they came in was torn apart soon after we got them. I didn't take the time to make it cute, but you certainly could with a little paper or washi tape.
I also have used these plastic trays that our yogurt cups come in for counting and sorting practice with my little ones.
I found this image online with no link, so I'm sorry for not giving credit, but these are beautiful holders made from cereal boxes! I can think of tons of ways to use these in the classroom: student boxes, monthly lesson plans, magazines or books!