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Yellow leaves on button fern: causes and fixes

Pellaea rotundifolia

Quick answer

Yellow leaves on your button fern have a few possible causes, and on this plant the likeliest is thirst.

Button fern (Pellaea rotundifolia)
Button fern · Pellaea rotundifolia
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First, check the soil. Push a finger 2 to 3 cm (0.8⁠–⁠1.2 in) into it and lift the pot. Dry and light means thirst. Wet and heavy means too much water or poor drainage.

Most likely cause

Thirst (underwatering)

Illustration of a wilting plant in dry, cracked soil with a watering can beside the pot

How to tell

  • The soil is bone dry, and the yellowing arrives alongside crispy leaflets with dry soil rather than soft, mushy growth.

The fix

  1. 1
    If the soil is dry, water thoroughly (every 6 to 8 days in summer is the usual pace for a button fern), then settle into feeling the soil before every watering rather than watering on a fixed day.

Other possible causes

Not a match? Compare the signs below to find the one you have.

Too little light

The yellowing comes with pale, stretched new growth leaning toward the nearest window.

The fix

  1. 1
    Move it to a brighter spot, but keep it out of harsh midday sun, which scorches.
More about this

That combination shows that the spot is too dim for a button fern.

Overwatering & early root rot

The soil is still wet days after watering, the lower and oldest leaves yellow first, and the stem base may feel soft.

How to tell

  • Small dark flies around moist potting medium may be fungus gnats.

The fix

  1. 1
    Stop watering.
  2. 2
    Make sure the pot can actually drain, and wait until the top 3 cm (1.2 in) of soil feel dry: ferns don’t like drying out.
  3. 3
    If the base is mushy or smells sour, unpot it and trim any brown, soft roots before repotting in fresh mix.

How to get rid of fungus gnats →

More about this

They suggest conditions suitable for breeding, without proving that the surface never dries.

Hungry (nutrient shortfall)

Older leaves fade to an even pale yellow and growth has clearly slowed.

How to tell

  • On a plant that likes 50–70% humidity and regular water, this shows up after many months in the same tired mix once feeding has lapsed.

The fix

  1. 1
    Feed with a balanced, diluted liquid fertilizer through the growing season, and refresh the top layer or repot if it’s been over a year.

Simple old age

A single bottom leaf slowly yellows while the rest of the plant looks healthy and is pushing new growth.

The fix

  1. 1
    Nothing is wrong.
  2. 2
    Snip the spent leaf off and carry on.
  3. 3
    Plants retire their oldest leaves.

All button fern guides

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