Across
- 3. the number of hardiness zones in the U. S.
- 7. short nights and long days
- 8. daily temperature change
- 9. color of light or width of each wavelength
- 11. hour amount most agricultural plants require
- 14. moving leaves towards light
- 15. zones the U.S. is divided into for plant growth
- 16. amount of time light is present
- 18. temperature where plants grow the best
Down
- 1. brightness of light
- 2. roots grow down towards gravity shoots grow up
- 4. light color of light plants grow best in
- 5. plants killed by frost
- 6. neutral unaffected by length of day
- 10. example of a cool season plant
- 11. long nights and short days
- 12. example of warm season plant
- 13. light that is reflected
- 17. season plants that can survive in mild spring frost