"I want you to weed the garden. I'll be back at three," the man said and drove away. It's gardening, Grandpa," Francisco said.

(In this passage, what does 'it' refer to?)

The "it" refers to weeding. It is saying that weeding is a part of gardening.

Be sure to put quotation marks just before "It's...

It seems to refer to the job that Grandpa is telling Francisco to do, the weeding.

To determine what "it" refers to in the given passage, we need to carefully analyze the context and the surrounding sentences. Let's break it down:

"I want you to weed the garden. I'll be back at three," the man said and drove away.
"It's gardening, Grandpa," Francisco said.

From the information provided, we can infer that Francisco is addressing his grandpa and referring to something related to gardening. However, the specific meaning of "it" is not explicitly mentioned in the given passage. To fully understand what "it" refers to, we may need additional context or information from a wider conversation or preceding sentences.

If more context or information is available, please provide it, so I can help you determine the referent for "it."