Why Are My Peace Lilies Dying?

Q: Many leaves on my 20-year-old peace lily are turning brown. I repotted it ten years ago. It stays in the window of a cool room and I water it once every other week. How do I make it healthier? 

A: I think it is way past time to repot your plant and change the soil. Potting soil naturally decomposes over time. It becomes harder for roots to grow through it as the soil particles become smaller. Take your plant out of the pot and wash all of the soil off the roots. You might find that you have multiple plants growing in the pot now. Use a sharp knife to separate them. Each one can be planted in its own pot for your future houseplant enjoyment or to pass on to your family.