Ask The Plant Expert: I've just got back from holiday and my peace lily's leaves are turning black at the edges. I watered it before I went 2 weeks ago, but the curtains have remained closed. Could the lack of sunlight be causing this, or the water? - Matthew Flower Shop Network Plant Expert Reply: Mathew, I am going to assume that water is the issue here, or possible cold temperatures. If the soil became dry while you were gone, the leaves would turn brown first, and then turn black. The peace lily would also appear to be wilting. If you turned your heat way down while you were out of town, the leaves would turn black. Both of these situation can be overcome. Begin by hydrating your soil. Make sure that all soil particles are rehydrated. However, you want to make sure that excess moisture can drain away from the peace lily plant. Then make sure the room with the peace lily is kept between 55-68 degrees at night, and 68-90 degrees during the day. I would [...]