Through evolution, all we earthlings - plants, animals and humans - were designed to live at a 24 hour lifecycle. This function is encoded in our DNA, that's why you can't grow your plants the way you wanted. The plant compares the light period to this 24 and will not think it's normal, it will think that it's been sprouted very late in autumn and starts growing flowers at once. Plants can adapt to different enviroments, but they can't rewrite their genetic code.

And if you light her with 6/6, she'll think: "The sun rises and sets in six hours?! WHAT THE FUCK IS GOING ON???"