Plants never thrive when they are potbound
Interesting research from Germany tells us what many suspected: Plants never thrive when they are potbound. Read about it in BBC Nature News:
"Plants grown in pots never reach their full potential, images of their roots show. A medical imaging technique called magnetic resonance imaging (MRI) has been used by researchers to capture plant pot root snapshots. The pictures reveal that the roots 'sense the size of the pot' and restrict the growth of the plant."
Here's an MRI of plant roots:
Here is a link that might be useful: Read more here