Mint: lower leaves turning yellow

What it is likely to be on mint

1. Pot-bound

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mint — care

   Checked 2026-08-13

   A root system that has filled its container and has nowhere left to go: roots circling the inside of the pot or emerging from the drainage holes, compost that dries out within a day of watering, and growth that has stalled despite feeding. The plant is short of both water and nutrients because there is almost no compost left to hold either.

   Points towards it

   • · a pot full of mint roots holds almost no water and dries within a day
   • · the lower leaves go first as the plant runs out of everything at once

   Argues against it

   • · a recently repotted plant has root room by definition — this rules it out entirely.

   Check this next

   Tip the pot out. A mint that has been in the same container for more than a season is a solid mass of white runners with hardly any compost left, and water runs straight down the side of it rather than soaking in.

   What to do now

   Split the clump, throw away the woody centre and replant a few vigorous runners in fresh compost. Mint is grown in a pot to contain it rather than because it likes one, so this is maintenance every year or two rather than a rescue.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mint — dividing

   Checked 2026-08-13

2. Seasonal dieback

   May be normalvery common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mint — growing

   Checked 2026-08-13

   A herbaceous perennial collapsing to nothing in autumn, or a seasonally dormant houseplant dropping most of its leaves in winter. The plant is intact underground and the top growth is expendable — an alocasia that has shed every leaf but has a firm corm is dormant, not dead, and is most often killed afterwards by being watered as though it were still growing.

   Points towards it

   • · an outdoor clump dies back to the roots every autumn and returns in spring
   • · the whole clump goes down together rather than in patches
   • · nothing has been done to it; the season has simply turned

   Argues against it

   • · a plant kept warm indoors is not responding to autumn

   Check this next

   Check the calendar before the plant. Mint yellowing and collapsing from late summer onwards outdoors is the normal end of its year, and scraping the compost surface will show fat white shoots already waiting at the base for spring.

   What to do now

   Cut the dead top growth away and leave the roots alone — it will come back stronger than it went down. This is the point in the year to divide an old congested clump if you were going to, because the roots are dormant and lift cleanly.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Mint — care

   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 mint — 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 Mint profile lists the problems it is prone to.