WATER! I have to check every day, all that growth sucks up a lot of h2o. I have my timer set for 14hrs on, going to cut back to 10 hrs on for 8 weeks in mid Dec.
I've been struggling with a small pot of variegated string of pearls. Two very hot days in late summer cooked it and I lost 60-70%. I moved it indoors a month ago and had about 1-2 inches from the t5ho. It didn't look happy so I set in at about 6-7 inches from the bulb. That's the sweet spot, I can see daily growth, it wants more water than you would think My regular string of pearls loves being very close to the bulb but not the variegated.