If it's only been one day then I'd switch the lights back, top them and wait for the new tops to form then change the lights back to 12/12. You might want to take the opportunity to trim any low branches as well.
Purple Daddy Reviewed by Purple Daddy on . advice needed please Hi Guys, my 1st post here. I am new to growing and have come across a 'big' problem. I am growing 8 plants in an NFT system, but I think the plants are gonna out grow my space. I have just switched lights to 12/12 yesterday. Due to space issues, it will be very difficult to bend them over, so is it safe to cut the tops off the plants, or is this frowned upon? Any help or advice would be greatly appreciated. Rating: 5