I prefer to delay *formal* grammar until grade 3, focusing on phonics, fluent reading, and beginning spelling in grades 1 and 2. However, we are using FLL this year in 2nd grade. It is gentle, not what I consider *formal* grammar, and it is a great way for me to be sure we get our narration and memory work in. ;)
We use 1 lesson per day, so we will finish the whole book in this year and can then move onto R&S English 3 in 3rd grade.