Most sunflowers develop pretty significant root systems, even small ones like these that mature at 1 to 2 feet, so give them about 10 inches—that a base (underground) of about one-third to one-half of the plant at maturity. It’s a rough gauge—you just don’t want the plants to be top heavy in pots that are too small.
Most sunflowers develop pretty significant root systems, even small ones like these that mature at 1 to 2 feet, so give them about 10 inches—that a base (underground) of about one-third to one-half of the plant at maturity. It’s a rough gauge—you just don’t want the plants to be top heavy in pots that are too small.