Yes, GREW is a Scrabble word!

verb

1. pass into a condition gradually, take on a specific property or attribute; become
2. become larger, greater, or bigger; expand or gain
3. increase in size by natural process
4. cause to grow or develop
5. develop and reach maturity; undergo maturation
6. come into existence; take on form or shape
7. cultivate by growing, often involving improvements by means of agricultural techniques
8. come to have or undergo a change of (physical features and attributes)
9. grow emotionally or mature
10. become attached by or as if by the process of growth