How does the air in space effect the growing rate of a plant?

Question: How does the air in space effect the growing rate of a plant?
- Keywords:
  effect,
  grow,
  plant,
  space
Asked by Holly to Delma on 4 Dec 2015.
- Delma Childers answered on 4 Dec 2015:
  
  I don’t recall the air on different space stations affecting plant growth so much, but gravity, light, and water definitely do. Most certainly, the vacuum of space would be quite problematic for plant growth. 🙂

Question: How does the air in space effect the growing rate of a plant?