Troubleshooting

Why are my pothos leaves turning yellow?

Almost always one of five things. Work down this list in order — the first two cost nothing to check and explain most cases.

First: is it just one old leaf?

If a single leaf low on the vine is going yellow while everything above it stays firm and green, that is normal. Plants retire old leaves and pull the useful material out of them before dropping them. Pinch it off and carry on.

Worry when several leaves turn at once, when new growth is affected, or when the yellowing comes alongside soft roots or smelly water.

1 · Stale water

The most common cause in a water-grown jar, and the easiest fix. Water that has sat too long goes low on oxygen and high on bacteria, and the plant responds by shedding leaves.

What to do

Change the water completely. Top the jar off weekly and replace the water entirely every one to two weeks — sooner if it looks cloudy or smells sour.

2 · Not enough light

Pothos survives in dim corners, but surviving and growing are different things. In low light it cannot support all its leaves, so it drops the oldest ones. You will usually see long bare stretches of stem between leaves as well, and the gold marbling fading on new growth.

What to do

Move it to bright, indirect light — a few feet back from a window that gets good daylight. Not a sunny windowsill, where direct sun will scorch it.

3 · Root trouble

Lift the plant out and look. Healthy water roots are pale cream or light tan, firm, and slightly see-through. Roots in trouble are dark brown to black, soft or slimy, and come apart when you touch them.

What to do

Trim away only the mushy, blackened parts with clean scissors and leave every firm root alone. Rinse what is left, scrub the jar, refill with fresh room-temperature water, and move it out of direct sun. A little browning with age is normal — softness and smell are the real warning signs, not color alone.

4 · Nothing to eat

Plain water contains almost none of the minerals a plant needs to build new tissue. A cutting coasts on what it stored for a surprisingly long time, then stalls — and older leaves start yellowing as the plant cannibalises them for material.

What to do

Use a fertilizer labeled for hydroponic or water-grown plants, start at the mildest dose on the label, and mix it into fresh water rather than pouring it onto the roots. Follow your own product's label; concentrations vary enormously between brands, so no guide can give you a number that is safe for every bottle.

5 · Too much fertilizer

The opposite problem, and it looks similar at a glance. Look for brown crispy leaf tips alongside the yellowing, and white crust on the glass or stones.

What to do

Stop feeding, change the water, rinse the roots and the jar, and go back to plain water for a few weeks.

Change one thing at a time

The temptation is to fix everything at once — new water, new spot, some fertilizer, a bigger jar. Do that and you will never learn which one mattered, and you will have stacked four changes onto a plant that was already stressed. Change one thing, then give it two to three weeks before judging.