These should have been put into flowering a long time ago.
That hydro system is meant for a few smaller plants.I would have flowered at about 1 1/2 feet.

If your going to cut it just to a small trim first.Don't cut too much or you'll shock your plant or kill it.
I'm more worrieed about your ROOT SPACE!!!!
Is it full of roots that are growing together.If it's running out of room they might die anyway.
If it comes down to it.You could kill every other plant and double it's grow space and root space.
But thats up to you.Take a pic of the roots! :thumbsup: