Why Are My Monstera Leaves Turning Yellow or Brown?

• Problems
• Watering

Photo by ignartonosbg on Pixabay

Yellow and brown monstera leaves usually mean too much water, too little light or a drying root ball. Here is how to tell which, and what to do first.

Start with the pot, not the leaf

Compost (potting mix) is what we call the stuff in the pot throughout. A yellow monstera leaf tells you something is wrong. The pot tells you what. Monsteras are forgiving plants, which is why they get overlooked until a leaf changes colour, and by then the cause has usually been running for weeks.

The pattern of yellowing helps. The RHS notes that other signs of overwatering include old and new leaves yellowing and dropping at the same time. On a dry plant the picture differs: older leaves at the base of the plant will often yellow and fall first. So ask which leaves are yellow, and whether you can see the same thing on the newest growth.

Our wider guide to why houseplant leaves turn yellow covers the general case. Here is what is specific to monsteras. Pothos shows the same pattern, and we cover it in why pothos leaves turn yellow.

Five checks that find the cause in a few minutes

1. 1

   Lift the pot

   A thirsty monstera in a pot of dried-out compost is light. A waterlogged one is heavy, even days after watering. Learn the weight of your plant just after a drink and this becomes your fastest test.

2. 2

   Push a finger into the compost

   Go in past the surface, to about the depth of your first knuckle. Dry all the way down means thirst. Cool and damp at that depth, days after the last watering, means the roots are sitting wet.

3. 3

   Check the saucer or cover pot

   Water collects out of sight in decorative outer pots. If the plant stands in it, the roots cannot breathe. Tip it away and do not put the plant back until the pot has drained.

4. 4

   Slide the plant out and look at the roots

   Healthy roots are firm and pale. Rotting roots are brown or black, soft, and often smell sour. This is the check that settles the argument.

5. 5

   Look at where the plant stands

   Note the window, the nearest radiator or door, and whether any leaf touches the glass. Light and temperature account for most cases the pot check does not explain.

For a plant you suspect of overwatering, the RHS suggests you lift it out of its pot to see if water has collected in the base, tipping away any excess. It also says that rather than watering at set intervals, it is good practice to check the moisture levels. Our guide to how often to water houseplants explains how.

If the compost is wet: overwatering and root rot

This is the most common reason for a yellowing monstera. Compost that stays wet drives the air out of the pot. The roots suffocate, then rot, and a plant with rotting roots cannot take up water even while standing in it. So the leaves yellow, and often droop, which looks exactly like thirst and tempts people to water again.

What to do:

• Stop watering until the compost has dried out well below the surface.
• Drain it properly. The Illinois Extension advises making sure pots are not sitting directly in water, so empty saucers and cover pots after every watering.
• Check the roots if the compost stays wet or the plant keeps yellowing. Cut away any soft, dark roots with clean scissors, shake off the soggiest compost and repot into fresh, free-draining houseplant compost in a pot with drainage holes.
• Do not go up a pot size. A big pot of compost that few roots can use stays wet for a long time. Match the pot to the roots you have left.
• Water lightly afterwards, and only once the top layer has dried. A monstera with fewer roots drinks much less than before.

Wet compost is also where fungus gnats breed, so tiny flies around the pot back up the diagnosis.

If the compost is bone dry: underwatering

A monstera left too dry also yellows, but the order differs. The lower, older leaves yellow and drop first, the compost shrinks away from the edge of the pot, and the pot is very light. The edges of leaves can go brown and crisp as well.

Water it slowly from the top until the compost takes the water and some runs out of the bottom, or stand the pot in a bowl of tepid water until the compost has soaked it up, then drain it fully. A hard, dry root ball repels a quick splash, which runs down the gap at the edge and out of the pot. After that, build a rhythm of checking rather than waiting for the plant to complain. Regular checks matter more than a fixed day of the week.

Brown leaves: sun, draughts and dry air

Brown without much yellow first usually means the leaf was damaged from outside.

Too much direct sun. The RHS says strong, direct sunlight, such as from a south-facing window in summer, can cause brown scorched patches on leaves. In the southern hemisphere, the same applies to a north-facing window. In plain terms, any window where the sun lands directly on the leaves for hours will scorch them. Pull the plant back from the glass, or filter the light with a sheer (net) curtain.

Draughts and cold. The RHS lists draughts as a cause of leaf yellowing and dry leaf edges, and blackened leaves, drooping and whole plant collapse as symptoms of cold damage. A monstera by a door that opens onto a cold hallway, or pressed against a single-glazed window on a winter night, can show it. Move it somewhere steadier.

Dry air near heat. Brown, crisp edges and tips often come from a radiator or heater close by. Our guide on plants near radiators covers how far is far enough, and brown tips on houseplant leaves goes through the remaining causes.

Low light and slow growth

A monstera in a dim corner grows slowly and uses little water, so it takes ages to dry out. That makes overwatering far more likely. The RHS lists weak, spindly growth and pale leaves among the signs that a plant is not getting enough light. If your monstera is pale, stretching towards the window and yellowing, move it to a brighter spot that avoids hours of direct sun, and water less often than you did before.

Yellow after repotting, and black leaves

After repotting. A plant with disturbed roots takes up less water, and fresh compost in a bigger pot stays wet for longer. Expect a leaf or two to yellow while it settles. Keep light and position steady, water only when the compost has dried a little at depth, and resist feeding it as a pick-me-up. Fertiliser on stressed roots does harm, not good.

Black leaves. Black means tissue has died quickly. The two usual causes are rot from long-term overwatering and cold damage. Slide the plant out and check the roots. If they are firm and pale, look at the temperature and the draughts instead.

What to do with the damaged leaves

Treat the cause first, then tidy up. The RHS advises cutting off mouldy, shrivelled, completely brown or completely yellow leaves with secateurs (pruners). Use clean scissors or pruners, cut at the base of the leaf stalk and leave any leaf that is only partly discoloured, because it is still feeding the plant.

A fully yellow leaf is finished. What you are watching for is the next leaf: if new growth comes through a healthy green and unfurls cleanly, you have fixed the problem.

Stop guessing which cause it is

The difficulty with a yellow monstera is that wet and dry compost both produce yellow leaves, and the deciding evidence is in the pot. That is the gap Folly is built to close.

Folly's Smart Care schedules set each plant's watering interval from more than fifteen attributes, so a monstera in a bright room and a monstera in a dim hallway get different intervals. Tap the plant and every factor is listed with the percentage it added or removed. Most apps hand you a number and ask for trust. Folly shows its working, so you can see whether the schedule is the problem rather than guessing.

If the pot check does not explain what you are seeing, photograph the leaf. Plant Doctor matches it against 500+ diseases, pests and deficiencies, with a step-by-step treatment plan, a recovery timeline and prevention notes. Chore day grouping, free, keeps watering and checking on days that suit you rather than scattered across the week.