you know that white tape type shit that you use on pvc piping threads? the shit that comes in a blue plastic roll that snaps into a white round outer casing?? U need to get that shit. Tape up your main stalks, n that stuff acts like a bandaid and can be removed hella easily. Once you have them tied up, then use your supports to hold up the stalks so they dont bend up. Itll probably take like a week or so, but your plant will heal for sure. Stuff like that happens to people all the time man, dont sweat it - my first grow i was just stupid and i snapped my main stem cuz i pulled on it too hard wheni pulled it towards me to check out the nugs. I i split that fucker right down the middle man, n i was heartbroken. But i took some of that tape shit and wrapped it around the stem TIGHT, and used a support. After a week she started binding back together. another benefit of using that threading tape is that you can take it off n put it back on without hurting anything, so you can check your stem frequently to see if shes healing herself.
The down side though, you need to be aware that the stress that your plants are gonna go through trying to heal might cause one or two of them to turn hermie, so you need to be on the lookout for that. Check every single innernode every day man.
Other than that, good luck man, n your plants will be just fine
***EDIT*** another thing that you need to do while your waiting for them to heal up, is foliar feed the top part of the plant that got broken. It sucks that you gotta do this cuz foliar feeding shouldnt be done during flower, but its the only way you can be sure the plant is uptaking any nutrients or water when you feed the lower half. After she heals you can go about feeding her as normal, but until then, just to be safe, foliar feed. If anything it will keep the top half alive until you decide what to do with the plant should something go wrong. You could always take the top half, soak the bottom of the stalk into some rooting gel, and replant it, LOL, but thats not the greatest idea in the world either
just do what your doin, n foliar feed (but keep it light).
