YOU SAID:
I like to help picking potatoes
INTO JAPANESE
私はジャガイモを選ぶのを手伝っています
BACK INTO ENGLISH
I am helping to pick potatoes
INTO JAPANESE
私はジャガイモを選ぶのを手伝っている
BACK INTO ENGLISH
I am helping to pick potatoes
That didn't even make that much sense in English.