That's a very powerful led and having it 12cm away would be your prob, heat stress as they are not only droopy they are coning in on each other. Check your lights recommend height distance. But it's a 1000watt so it must be in the 1500-3000 ppfd 500-1000 par, thats way to close. Around 30cm but again I'd check your light cause Its usually 30-40cm from a 100-600watt so check ur lights brand instructions. Good luck.