Minecraft wiki entry for The_second_day, associated text: As you explore your world, you are likely to pick up some dirt blocks. These are not good for building structures, but they are quick to place and remove, so you can use them for temporary staircases, pillars, and such. More importantly, you can use them to modify the landscape, making it easier to get around near your home. If you've had a creeper explode nearby, you can also use your collected dirt to fill in the hole (immediately after the explosion, there may be dirt and perhaps stone items left in the crater. Pick those up, but don't expect to get enough to fill in the crater). Note that mining grass blocks (that is, full blocks with a green top, not "tall grass" plants) drop dirt — don't worry about the difference for now. If you place the dirt next to grass blocks, the grass eventually spreads to the dirt, cleaning up the "scars" of your work.