Yes, your interpretation is correct.
심으시고 is 심으시다 in the -고 connective ending which is like an "and" connection.
You would normally say 작물을 많이 키우시고 고구마도 심으신다, but 작물을 많이 키우신다. 고구마도 심으시고 is also possible, as when you think of something to add after finishing the first sentence, like "In addition / Also, ..."
심으시다 is the honorific version of 심다 (to sow) showing respect for the subject of the verb.
"아버지를 닮은 것도 있지만 제가 아버지를 닮고 싶어 하는 것도 굉장히 많아요" (굉강히 -> 굉장히) has two parts.
- 아버지를 닮은 것도 있지만 = while there are things(것) I take after (닮은) my father = while I take after my father in some ways.
- 제가 아버지를 닮고 싶어 하는 것도 굉장히 많아요 = there are also so many (굉장히 많아요) things (것) that I would rather be / I wish I was like my father.
- While I take after my father in some ways, there are many more ways that I wish I was like him.