Shiitake Mushroom Growing Block Kit Contains: One ready to start sawdust block inoculated with mycelium. First mushrooms grow usually within 2 weeks after starting the kit. Best Temperature for Growing: 65 - 68 degrees Fahrenheit plus or minus 5 degrees. Kit Dimensions: Length 9.5",Width 7.25",Height 7.5" Usually ships within 2-3 days.