We recently got a big cardboard box that the kids quickly had torn up. I cut off a few pieces of it thinking the panels would come in handy for some art projects. For this one, we went and got a bowl full of dirt from outside. I had wanted to do it outside but the weather changed those plans for us. Anyway, the kids painted on some colored glue onto the cardboard then sprinkled the dirt on top of it. We let it dry and then shook off the dirt that didn't glue. It has a really different texture. I did have the kids put their dirt projects in containers to "contain" the dirt but it still got everywhere. Just a word of caution....
When the dirt and glue dried, we painted the dirt creation. It was quite a different sensory experience and they both noticed that it was much different painted on dirt than just paper.
Super cool (messy) project!