what to do for the girls?

im wondering if there isnt enough sun this summer. and the plants have grown to a decent size can they enter the flowering stage on their own? and still be dense nugs? or can they be covered completely for the 12/12 stage?

depends on your area , what the weather does and when your sun rise and set cause the plant to convert to flowering ....if you get hard freezes in oct then no it won't finish here in south texas we may not get a freeze until march if at all, so you have to know more about your conditions