This plugin allows you to use bonemeal on dirt to turn it into grass blocks.

If you have a permissions plugin, make sure your players have the permission "bonemealdirt.use"
This resource is part of my custom series. You can view the full list here, prefixed by [Custom]. This series comprises of custom requests from server owners, where I help them out for free and in exchange, I keep all rights to the resource. I am releasing them here for any other server owners who can find a use for them.