The "planet of origin" of the Krynoids was located in the Mutter's Spiral. The Fourth Doctor theorised that it was possibly a very turbulent planet from time to time, and that internal explosions could cause surface matter to go shooting into space, launching Krynoid seed pods into the galaxy. (TV: The Seeds of Doom) He also considered that the cold of Antarctica could be considered "glorious summer" on the Krynoid planet. (PROSE: Doctor Who and the Seeds of Doom)
Eve Black hallucinated about the possible Krynoid homeworld, and watched a creature like a giant hummingbird get eaten by a plant. (AUDIO: The Root of All Evil)