How do I get into the computer in the greenhouse?

Hint 1 of 4:

Did you notice what happened when the puke monster attacked you?

Hint 2 of 4:

He dropped a slip of paper to the left of the computer.

Hint 3 of 4:

Pick it up.  That has a five-digit code.

Hint 4 of 4:

And you need to input a five-digit number into the computer.