It’s a buildup of mineral salts from hard tap water or fertiliser. Switching to rainwater or filtered water, and feeding only in spring and summer, will help
What’s the problem?
There is a chalky white crust on the top of my spider plant’s potting mix, and the leaf tips are turning brown. Why is this happening and how do I fix it?
Diagnosis
This is a buildup of mineral salts from hard tap water or fertiliser. As water evaporates, salts are left behind and come to the surface. Over time, they concentrate around the roots, drawing out moisture and scorching sensitive tissues, which shows up as brown, papery leaf tips and edges. It can also throw off the soil pH, so plants struggle to absorb nutrients.
