Like most other commercial crops where the seeds or fruits are not the primary
crop, tobacco seeds are usually pinched off in the field.  Otherwise, the plant
will spend much of its energy growing the seeds instead of the more valuable
leaves.  Leaving the seeds also makes a much stronger tobacco than if the seeds
were pinched off.
 
However, some extra fine sieving, or better yet, flotation might reveal
interesting results.  I would recommend the attempt.  For easily accessable
information on tobacco growing (not meant to be a commercial plug) see:
 
The Tobacco Growing Discussion Room at:
http;www.tobacco.co.uk/growingboard/wwwboard.html
 
or
 
Grow Your Own Tobacco In Your Own Garden at
http://www.bcity.com/oztobacco/index.html?inFrame
 
Hopes this helps,
Smoke Pfeiffer
 
 
 
***********************************
Smoke (Michael A. ) Pfeiffer
Archaeologist
Ozark-St. Francis National Forests
605 West Main Street
Russellville, AR 72801
[log in to unmask]
***********************************