Basil: plant wilting although the soil is moist

What it is likely to be on basil

1. Root rot

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Basil — problems

   Checked 2026-08-13

   The consequence of prolonged waterlogging rather than an independent event: water moulds that are present in most soil and compost become active when roots are deprived of air, and colonise tissue that is already dying. The treatment is therefore the watering, not the fungus.

   Points towards it

   • · basil roots die quickly in compost that stays saturated
   • · the whole plant goes limp at once when the roots have failed
   • · a supermarket pot with no drainage hole, watered on a schedule, is the commonest way this happens

   Argues against it

   • · roots cannot be rotting in compost that is dry — this rules it out entirely.

   Check this next

   Slide the whole plant out of its pot and look at the roots. Healthy basil roots are white and firm and smell of nothing; rotted ones are brown, soft, and pull away from the stem when you touch them.

   What to do now

   Stop watering and let the compost dry until the pot feels light. If most roots are already brown there is no recovery, but basil roots readily from a cutting — take a healthy shoot tip, strip the lower leaves and stand it in water, which saves the plant rather than the pot.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Basil — care

   Checked 2026-08-13

2. Cold damage

   Candidate 2very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Basil — hardiness

   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

   • · basil collapses after a single cold night, and below 10 °C is enough
   • · outdoors in Britain is below basil's tolerance for most of the year

   Argues against it

   • · cold damage follows a specific event; a plant in a steady warm spot has not been chilled

   Check this next

   Look at the leaf edges rather than the roots. Cold turns basil's leaf margins black or translucent within a day or two while the stem stays firm and the compost smells clean — rot works the other way round, from the bottom up.

   What to do now

   Move it somewhere that stays above 12 °C overnight and leave it alone for a week before deciding what is dead. Do not water it to perk it up: chilled roots cannot take up what is already there, and adding more is how a cold basil becomes a rotted one.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Basil — growing

   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 basil — 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 plant wilting although the soil is moist page lists causes across all plants, and the Basil profile lists the problems it is prone to.