I like the concept of what they are using to contain heat. Probably build it differently I like to take other people's ideas then improve them .... http://www.thenorthwestgardener.info/2011/03/cheap-seedling-box.html?fbclid=IwAR0NAaqwMl5XQ31PJCp2lkYrckG8mD35HY9XeWgJ38Myao2XHdneLAa9jEE