I also experienced slow growth with my B+s.... Do you still have the tape on your jars??? I took my tape off and the mycelium was very happy and rewarded me with fast growth. Defintaly make sure your jars are in an area that is at about 80-86F as Thunderfuck suggested.------------------
"My mind dont work if my spine dont jerk"
-Quote from Eminem-
~PanTrop~