Fluoride or chlorine sensitivity

What's happening

Spider plants are unusually sensitive to the fluoride, chlorine, and dissolved salts in municipal tap water. Those chemicals build up in the soil and accumulate at the very tips of the long leaves — the farthest point from the roots — where they burn the tissue brown while the rest of the leaf stays green.

How to fix it

Switch to a low-mineral water source: collected rainwater, distilled water, or tap water left out uncovered overnight so some chlorine can off-gas. Once a month, flush the pot by running plenty of plain water through the soil until it drains freely, to wash out accumulated salts. The existing brown tips won't turn green again, so trim them off with clean scissors — cut at an angle following the leaf's natural point — and new growth should come in clean.

This is general guidance based on common symptoms; individual plants vary.