Growing the growing season

It  would   be  great  to have  cold  weather   crops under  production  this  fall  and  winter.
The  secret  garden  is protected and  likely gets  some radiated  heat  from  the  building  in the
cold  months.  How  much  sun infiltrates  the   space   as  the    sun  sits  lower  in  the  southern   sky I  have   yet  determine  but think the upper  portion  of the  north  wall  should  get  some  . That  should   provide  heat  and  reflected   light  that  a  green house    could  capitalize  on.  Broccoli,  cabbage,
and  lettuce might  be  possible  to  grow throughout  the  winter.  

My  thought is  to build something  like     this  in  modular  pieces so  that  the  covering  could  be   removed
in  the    summer.  Hanging   plants  could    be  supported in  the   upper    portion  of  the  structure where  they  would   catch  winter  light.  Even  in  the  summer  the  structure  would  provide  vertical    growing   possibilities.
One  of  the  gutters units could  be    enclosed  as  a  germinating location  in  early   spring.
Going  to  put  numbers  on  one  unit and  my    hunch is  it  would  not   cost    that   much if  done  right.
Inspired  by  the  Man    of  La  Mancha. :)   Richard T.  and  Shannon C.  suggested  60  degree  angle   for    roof  line   so  that's  what  it  has.

This in  ground    garden I really  kickin'  it.  Can't  wait  for  those tomatoes.