Why Houseplant Leaves Turn Yellow in Winter: 7 Causes and Fixes

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You walked past your pothos this morning and a leaf that was green last week is now bright yellow. By the end of the month it might be three or four. The short answer is that winter yellowing almost always comes from a change in the plant’s conditions, and the most common change is too much water for the amount of light the plant is getting.

Most of the causes below are easy to check in about ten minutes. Start with the soil, then look at the light and the spot where the pot sits. We have put the causes roughly in the order we would check them. University extension services, which we link to as we go, back up each one.

1. Too much water

This is the first thing to rule out. Plants grow slowly in winter and use less water, so the same weekly routine that worked in July can leave the soil soggy in January. Extra moisture cuts off air to the roots, and Cornell Cooperative Extension lists overwatering and poor drainage among the main reasons for yellow foliage. The University of Kentucky notes that yellowing and dropping leaves often point to overwatering.

The fix: push a finger one to two inches into the soil. If it feels damp, wait a few days and check again. Make sure the pot has a drainage hole and empty the saucer within an hour of watering. Our guide to how often to water houseplants in winter breaks the timing down by plant type.

2. Not enough light

Winter sun is weaker and sits lower in the sky, so a spot that was bright in summer can be dim now. University of Kentucky Extension recommends a south or west window in winter, set back a little from the glass so the plant is not hit by cold air. Low light also shows up as lower leaves that yellow and drop first while new growth stretches toward the window.

The fix: move the plant closer to the brightest window, or add a lamp overhead. Iowa State University Extension advises changing light levels gradually, so shift the plant a little at a time instead of all at once.

3. Cold drafts and sudden temperature swings

Leaves near a drafty window, an exterior door or a heating vent often yellow on one side only. Iowa State University Extension names sudden blasts of cold or warm air as a cause of yellowing and leaf drop, and says to keep temperatures steady.

The fix: move the pot away from the door, the glass and the vent. If a plant has to sit at a window, slide a piece of cardboard or a folded towel between the leaves and the glass on the coldest nights.

4. Dry indoor air

Heated homes can be 10 to 20 percent drier than the rest of the year, according to University of Kentucky Extension. Dry air tends to cause brown, crispy edges first, but Iowa State lists low humidity among the causes of leaf drop, and a stressed plant may yellow along with it.

The fix: group plants together so they share the moisture their leaves give off. You can also set pots on a tray of pebbles with water just below the tops of the stones, so the pots stay dry. A bathroom or kitchen with a bright window is a good home for plants that like humidity.

5. Too much heat at night

Cornell Cooperative Extension says high temperatures, especially at night, lower a plant’s vigor and can lead to yellowing. A pot on top of a radiator or beside a space heater is a common culprit.

The fix: Cornell suggests keeping plants cooler at night, ideally 60 to 65 degrees Fahrenheit, and away from heat sources. A spare room that stays a little cooler can work well.

6. Feeding at the wrong time

Too little fertilizer can turn leaves pale yellow, and too much can burn the roots. Extension sources do not fully agree on winter feeding. Cornell suggests feeding every five to six weeks in winter, while University of Kentucky Extension says to skip fertilizer until new growth appears in early spring.

The fix: if your plant is growing slowly and sits in a dim room, holding off on fertilizer is the safer choice. If it is in bright light and still pushing out new leaves, a light feeding every five to six weeks is reasonable. Never fertilize a plant with dry, stressed roots.

7. Pests and crowded roots

University of Georgia Extension lists scale and spider mites as causes of yellow leaves, along with older plants that have become pot-bound. University of Minnesota Extension names spider mites, mealybugs, scale, fungus gnats and whiteflies as the usual indoor pests. Check the undersides of leaves and the stems for webbing, sticky residue or small bumps. Roots circling the drainage hole are the sign of a pot-bound plant.

The fix: isolate any plant with pests so they do not spread, and treat early. For crowded roots, move up one pot size only. Minnesota recommends increasing the diameter by no more than two to three inches. Winter is not the best time for a big repot, so see our guide on repotting your plants before you start.

When a yellow leaf is normal

One yellow leaf near the bottom of a plant now and then is just a leaf reaching the end of its life. University of Georgia Extension says an occasional leaf dropping as it ages is normal. Worry when several leaves yellow at once, when new growth turns yellow, or when the yellowing spreads from one week to the next.

What to do with the yellow leaves

A leaf that has turned fully yellow will not go green again. Snip it off at the base with clean scissors so the plant stops spending energy on it. Then change one thing at a time, usually the watering first, and give the plant two to three weeks before judging the result. Changing everything at once makes it hard to tell what helped. For other problems you may spot along the way, our post on common plant problems covers more of the usual suspects, and our look at indoor plant care through the seasons shows how needs shift through the year.

FAQ

Can a plant with yellow leaves recover?

Yes, if you fix the cause. The yellow leaves will not recover, but new growth should come in green once the plant’s conditions improve.

Should I cut off yellow leaves?

Once a leaf is mostly yellow, yes. Trimming it keeps the plant tidy and lets you see whether new leaves are staying healthy.

How do I tell overwatering from underwatering?

Check the soil. Soggy soil with yellow, drooping leaves points to too much water. Bone-dry soil with crisp, shrinking leaves points to too little. University of Kentucky Extension notes that rapid leaf drop can also mean the plant needs water.

Want a quick way to match symptoms to causes? Our free Houseplant Rescue Cheat Sheet covers yellow leaves and other common warning signs, and you can get it here.

Ginger Durett has more than 10 years of experience as a professional grower, including general growing and medicinal cannabis growing. Blair Sutherland is a co-founder of Happy Healthy Living.