Black Nebula Carrots are ready for harvest in around 58 days. These purple carrots reach around 6 to 8 inches in length. Approximately 180,000 to 500,000 seeds per pound.Black Nebula Carrots have purple skin with an orange core. This variety resists breaking and splitting.Germinate at 78 degrees Fahrenheit for 14 to 21 days. Cover with 1/4 inch of soil.