The plants are starting at -3, I would say that the plants can grow further down past negative three.
I would draw an open circle at -3, then have the arrow pointing to the left. This shows that the roots can grow lower than -3.
Depending on what numbers I'm rounding to, hundreds, tens, ones etc
If the ones place is 4 and lower, I would round to 30. If the ones place is 5 and higher, you would round to the next tens place. That would make 89 to 90.
Hope This Helps!
