Calathea: lower leaves turning yellow

What it is likely to be on calathea

1. Cold damage

   Candidate 1common on this plant

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Houseplants — siting

   Checked 2026-08-13

   Blackened, translucent or limp tissue appearing suddenly after a cold night or a spell beside a draught. Tender plants show it well above freezing — basil blackens around 10 °C — so 'there has been no frost' does not rule it out.

   Points towards it

   • · a calathea is a rainforest floor plant that suffers below about 15°C, and a windowsill behind a closed curtain in January is colder than the room
   • · an indoor siting problem
   • · the leaves nearest the glass or the draught go first

   Argues against it

   • · nothing changed, and this cause needs an exposure that was not there before
   • · wet compost is the other main reason a calathea yellows and should be excluded before cold is blamed

   Check this next

   Put your hand where the plant sits, last thing on a cold evening, and then check which leaves are affected. A calathea chilled behind a curtain or beside a draughty frame yellows the leaves on the cold side first and the damage stops where the cold does — a sharp boundary across the plant is the signature, and a plant yellowing evenly all over has a different problem.

   What to do now

   Move it off the windowsill into the body of the room for the winter and keep it away from doors and unheated porches. Reduce watering while it is cold, because a chilled root ball in wet compost is the combination that turns a recoverable setback into root rot.

   ·source

   Sourced guidancemoderate confidence

   • Royal Horticultural Society: Houseplants — siting

   Checked 2026-08-13

2. Overwatering

   Candidate 2very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Overwatering

   Checked 2026-08-13

   Not a matter of volume but of frequency: roots need air as well as water, and compost that never dries suffocates them. It kills more houseplants than every pest and disease combined, and its cruellest feature is that the early signs — yellowing, wilting, dropping leaves — look exactly like drought, so the instinct is to water more.

   Points towards it

   • · calathea is famous for wanting moisture, and the advice is routinely over-applied until the compost never dries at all
   • · an indoor problem
   • · failing roots yellow leaves right across the plant rather than on one side

   Argues against it

   • · the compost is dry, so the roots are not waterlogged — this rules it out entirely.
   • · a recent chill explains a sudden yellowing better than a gradual root decline

   Check this next

   Separate the two things people mean by 'humidity' before deciding. A calathea wants damp AIR and merely moist compost, and the failure mode is treating the second as a way of achieving the first: if the compost has not dried even at the surface between waterings for weeks and the yellow leaves feel limp rather than crisp, the roots are the problem and misting was never going to fix it.

   What to do now

   Let the top two or three centimetres dry before watering again, and stand the pot on a tray of damp pebbles rather than watering more often. If the yellowing continues, slide the plant out and look for roots that are brown and soft instead of firm and pale — that changes the job from watering less to repotting into fresh compost.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Overwatering — recovery

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on calathea — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general lower leaves turning yellow page lists causes across all plants, and the Calathea profile lists the problems it is prone to.