What is the difference between växa and öka?
Both can be translated "to grow" or "to increase." Sometimes the Duolingo grader seems to allow these two Swedish verbs to be used interchangeably but sometimes not. It seems to me that växa usually refers to physical growth (of plants, animals, or children, for example) while öka refers to growth of numbers (population, unemployment rate, etc.). Am I on the right track?
You are on the right track, I think. In my opinion it's more or less like this: växa = to grow, öka = to increase. While you often can use växa as to increase, I wouldn't use öka for growth in physical size (thought it is possible if worded right) . I'd like to think that in first hand, växa is used mainly when talking about size and öka when talking about numbers or amounts.
Yes you are.