Troubleshooting Common Issues

When a first closed jar looks poorly, beginners water it, move it, and open it all in the same afternoon. Then nobody knows what helped. The method is slower than the panic: look, change one thing, wait.

This page is for collapse and plant symptoms. Fog lives on the watering page. White fluff lives on mould vs mycelium. Send people there first if that is what they are actually seeing.

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A notepad beside the jar with three lines filled in — “Fittonia floppy / mix dry / glass clear” — so the method is visible. Real handwriting, not a graphic.

The method

1. Write down what you see (which plant, wet or dry mix, glass weather, smell).
2. Change one of: water, light/place, or debris.
3. Wait several days (Fittonia thirst wilt is the exception — that can recover in under an hour).
4. Only then change the next thing.

RHS houseplant first aid is the same shape: check water, light, temperature, then cut off what will not recover. A sealed jar just makes overwatering faster and underwatering rarer.

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A simple three-box card on the table — Water / Light / Debris — one box circled. Prefer a physical card over a UI mock.

Yellow

In a closed tropical jar, yellowing leaves are usually too much water, not hunger. Excess condensation leads to rot if you ignore it. Take yellow and dead tissue out of the glass so it does not mould.

Confounders:

• Fittonia yellow from gloom, not wet — pale, stretched, still firm. Move to brighter shade, do not add water.
• Fittonia yellow from wet feet — lower leaves, mix soggy, glass never clears. Vent and siphon.
• Pilea depressa yellowing or curling — too much water, too little, or not enough light. Confirm against the glass weather before you add mist.
• Old leaves. A few lower leaves ageing is normal. A sudden flush of yellow is not.

Do not dose liquid feed into a sealed beginner jar to “fix yellow.” Feed is not the first lever.

Media (still)

Fittonia with yellow lower leaves over wet mix (wet-feet) beside a pale stretched Fittonia in a gloomy corner (gloom). Caption which is which.

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10–15s: tweezers taking a yellow leaf out of the jar onto paper. End on empty tweezers.

Mush (rot)

Mushy Pilea depressa stems, black Fittonia crowns: too wet, too still, sometimes too cold. Fittonia dislikes waterlogged compost even though it loves humidity. Cold draughts and between-curtain windowsills in a UK winter make rot more likely.

First steps: cut away mush with clean scissors, remove it from the jar, vent, stop watering. Leave the lid off long enough that the mix is damp, not glossy. If a stem is brown and squashy all the way down, that plant is done — replace it rather than nursing jelly.

After a heavy prune, air the jar 30–60 minutes. Clippings left in are a reliable way to get mould.

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Macro: a Pilea depressa stem that is squashy and brown vs a firm green trail. Side by side on damp kitchen paper, not inside a wrecked jar if you can avoid stressing a display.

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15–20s: clean snips cutting mush, bits landing on paper, lid left ajar. Daylight. No music.

Brown moss

Cushion moss browns at the tips when it dries or cooks. Clear glass for days, lid gaps, or sun through glass are the usual UK causes. A light mist on the moss only — not a soak of the mix — and a move to bright shade is the first fix.

Brown and slimy is the opposite problem: underwatered-then-flooded, or constant wet in gloom. Do not answer brown with a flood. Check the glass.

Pale or yellow moss with dry, shrunken mix is a dry cue: a small amount of water, then wait.

Never collect wild moss to “replace the brown bit” unless you own the land and know it is clean. Buy cultivated moss.

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Brown crispy moss tips (dry/sun) vs brown slimy moss (wet). Two cushions.

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8–10s: one or two sprays on moss only, not a shower of the mix.

This jar, specifically

Nerve plant (Fittonia albivenis). Dramatic faint when dry; usually stands up after a drink, often within the hour in a pot — in a jar, use a pipette, not a thorough drench. Repeated collapsing weakens it. Brown crispy edges: low humidity or heat/sun — in a closed jar that usually means a leaky lid or a hot windowsill, not a need to mist more. Keep warm (about 15–17°C or above) and out of draughts. Grey mould on damaged leaves: pick off.

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20–40s if you can: Fittonia fainted flat, pipette at the roots, then the same plant standing again. If recovery takes longer in a jar than a pot, say so in the caption — do not fake a 30-minute miracle. A before still + after still with times written on a card is honest if a clip is awkward.

Cushion moss (Leucobryum). Surface pearly-green is the aim. Brown tips: dry or harsh light. Slime: wet. It is a humidity buffer, not a sponge you drown.

Pilea depressa. Tiny round glossy leaves on trailing stems. Small pileas suit terrariums; avoid overwatering; grey mould shows up in still humidity. Faster and greener than P. glauca, so pinch it before it blankets the moss. Not Chinese money plant (P. peperomioides). Not Soleirolia, even when a UK shop calls it baby tears.

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Pilea depressa in the first jar — round leaves trailing over cork — with a handwritten label “Pilea depressa”. Optional contrast still of P. peperomioides (disc leaves on stalks) marked “not this one.”

Later warning — Soleirolia soleirolii (true baby tears). Not in this trio. It creeps, roots as it goes, and smothers neighbours in a tiny jar. If someone added it, shear it back or take it out.

Closed Tropical Mix. If it smells sour and looks like mud, water and air have failed. Fluff the surface only if you can do it without wrecking roots. Recurring swamp: rebuild drainage, start damper-not-wet, cycle again. Springtails after that, not into the swamp.

Wrong plant. A succulent or haworthia in this sealed tropical set will collapse. That is a plant-list error, not a watering puzzle. Swap it out.

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A haworthia or similar succulent in a closed humid jar looking unhappy — or a “do not” card on an open arid bowl as the contrast exit.

When to replace a plant

Replace when stems are mushy throughout, roots are brown slime, no new growth after many weeks, or the same fungal mess returns on that plant alone. A healthy spare Fittonia or Pilea depressa cutting is cheaper than another month of fiddling.

What not to do

• Do not move and flood and add springtails on the same day.
• Do not put the jar in a south window “to dry it out.”
• Do not use pesticides or copper in a jar that will host springtails.
• Do not oven-bake living plants.
• Do not treat history or “self-sustaining” as a promise that nothing dies.

Science note

Yellowing from wet soil is roots losing air, not a mystery nutrient crash. Fittonia’s faint is a fast wilt when the mix cannot supply the leaves — dramatic, often reversible. Pilea depressa trails and fills; Soleirolia smothers — that is why only depressa is in the first jar. None of that needs numbers on the page.