Houseplant clinic: why is there a chalky crust on my plant's soil?

"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."

"Run tepid tap water through the mix for a few minutes until plenty of water drains out. Repeat a week later. If the crust is heavy or the mix is compacted, repot in fresh, free-draining, peat-free compost and clean the pot before reusing it. Trim crisped tips with clean scissors, mirroring the natural shape of the leaf. Switch to rainwater, filtered water or boiled and cooled tap water."

There is a chalky white crust on potting mix and brown leaf tips due to salt accumulation. Mineral salts from hard tap water or fertiliser remain as water evaporates and migrate to the surface. Salts concentrate around roots, drawing out moisture and scorching sensitive tissues, resulting in brown, papery leaf tips and edges. High salt levels can alter soil pH and impair nutrient uptake. Remedy by flushing the pot with tepid water until clear drainage, repeating after a week, and repotting into free-draining, peat-free compost if the mix is compacted. Use rainwater or filtered/boiled and cooled tap water, feed only in active growth, and flush containers monthly.

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