Yellow leaves are the most common way a plant asks for help — and for beginners, the most confusing. The good news: there are only a handful of causes, and each one leaves a clear clue. This guide walks you through how to diagnose and fix yellow leaves, fast.
Start with the most likely cause: overwatering
If your plant has yellowing lower leaves and the soil feels damp, overwatering is almost certainly the culprit. It’s the number one killer of home plants. Roots sitting in soggy soil can’t breathe, so the plant drops its older leaves.
The fix:
- Do the finger test — push a finger 3 cm into the soil. If it’s damp, wait to water.
- Only water when the top few centimetres are dry, then water deeply until it drains out the bottom.
- Make sure the pot has a drainage hole and never let it sit in a saucer of water.
Then check drainage
Even with careful watering, a pot with no drainage hole traps water at the bottom and rots the roots. If you’re not sure your pot drains, tip it after watering — water should run out freely. No drainage hole? Repot into one that has it. This single fix prevents most yellow-leaf problems.
Too little light
If the whole plant looks pale and washed-out, and it’s grown tall and thin reaching for the window, it isn’t getting enough light. Herbs and vegetables want bright light — most need 4–6 hours of direct sun a day.
The fix: move it to your brightest windowsill (south- or west-facing is ideal), and rotate the pot every few days so all sides get sun.
Hunger (needs feeding)
A plant that’s been in the same pot for a while can simply run out of nutrients — this shows as an overall pale-green to yellow color, often starting with older leaves. This is common once a plant hits its active growing phase.
The fix: feed it. A gentle organic option like diluted compost or worm-castings “tea” every couple of weeks is plenty for kitchen herbs and greens.
Underwatering (less common, but it happens)
If leaves are yellow with dry, crispy brown edges and the soil is bone dry and pulling away from the pot, the plant is thirsty. Water deeply, and going forward don’t let the soil dry out completely between waterings.
A quick diagnosis cheat-sheet
- Lower leaves yellow + soil damp → overwatering. Water less; check drainage.
- Whole plant pale + leggy → not enough light. Move to a brighter spot.
- Overall pale, older leaves first → hungry. Feed it.
- Yellow with crispy brown edges + dry soil → underwatering. Water deeply.
- A few old bottom leaves yellowing slowly → often normal aging. Nothing to worry about.
When yellow leaves are normal
Don’t panic over a single old leaf. Plants naturally shed their oldest, lowest leaves as they grow — that leaf did its job. It’s only a problem when several leaves yellow at once, or new growth is affected.
Most yellow-leaf issues come down to water and drainage. Nail those two, give your plant enough light, and the rest usually takes care of itself.
Growing herbs or vegetables and want to get watering exactly right? Our guides on growing basil at home and the easiest microgreens to grow walk you through it step by step.