Hello all. I bought 2 yucca cane's from Home Depot approx 2 months ago. I put them in soil mixed 1/3 potting soil, 1/3 perlite, 1/3 sand. I water when the moisture meter says the soil is dry. I thought it was lack of sun so I got a UV light that's on for 8 hours a day. They are at a S-SW window. I really have no idea what else to do but they are dying pretty fast and it's very concerning.

Any help would be GREATLY appreciated. Thanks in advance!