Depends. I plant my Greigii and Kaufmannianas about 6 inches but I plant the others, like the Darwins, triumphs, single early at about 8 inches and then I plant the Emperors 10 inches deep. I plant them close together. So about one bulb space apart. Like in a row a bulb, a space the size of the bulbs, next bulb. And multiple rows in a grid like that also. I put them close together.
