Plant care guide
Aloe Vera Yellow Leaves: Overwatering, Thirst, Sun or Age?
Updated
Why are my Aloe vera leaves turning yellow?
Yellow aloe leaves that are also soft or mushy, on mix that stays damp, point to overwatering and root rot. Thin, shrivelled yellow leaves on dry mix point to thirst, and a dried lower leaf now and then is normal. Yellow sap oozing from a cut leaf is latex, a normal part of the plant, not a symptom.
What to do first
Squeeze the yellow leaf and push a finger into the mix. Soft leaf and wet mix: stop watering and check the roots. Wrinkled leaf and dry mix: water thoroughly. A single dry lower leaf can simply be removed.
A yellowing aloe is worth a close look, but the color alone does not tell you the cause. How the leaf feels, where it sits on the plant, and how wet the mix is will narrow it down in a few minutes.
One thing first. If you cut a leaf and yellow liquid seeps out, that is not a disease. It is aloe latex, covered in the last section below.
Read the leaf and the mix
Squeeze the yellow leaf gently, push a finger into the mix, and lift the pot.
| What you find | Likely cause |
|---|---|
| Yellow, soft or mushy leaves, mix still damp, maybe fungus gnats or mold on the surface | Overwatering, possibly root rot |
| Yellow leaves that are thin, wrinkled or shrivelled, dry and light pot | Underwatering |
| Yellow or tan patches on the side facing the window, soon after a move | Sun damage |
| Pale, yellow-green new leaves that are thin and stretched | Too little light |
| One or two outer, lowest leaves drying, rest of plant firm | Normal ageing |
Overwatering. This is the one to rule out first. Iowa State University Extension’s succulent problems guide says succulents kept wet develop yellowing, soft and mushy leaves and stems, and leaves eventually drop. The soil surface stays damp, and in severe cases you may see mold or fungus gnats. NC State Extension’s aloe profile says to let the soil dry completely between waterings. Penn State Extension’s aloe article notes that aloes are susceptible to root rot.
Underwatering. Iowa State describes underwatered succulents whose leaves yellow, shrivel and brown before dropping. Leaves may also look wrinkled and mottled. Root rot can mimic this: Iowa State warns that plants with rotted roots shrivel too, and are often given more water by mistake. So check the mix before you water.
Sun stress. UF/IFAS Extension’s aloe page warns that aloe can sunburn when moved from low to bright light too quickly. Iowa State describes the damage as brown or tan patches that do not recover. Strong light more often turns aloe red, orange or bronze. Our article on why aloe turns red explains how to tell harmless stress color from burn.
Low light. Iowa State lists pale, spindly new growth as a sign that light is too low. If the new leaves are yellow-green and stretched, see our aloe etiolation guide.
Age. Iowa State notes that the lower leaves on rosette-forming succulents occasionally dry up and fall off. If the plant is otherwise healthy, a dried lower leaf or two is no cause for concern.
What to do
If leaves are soft and the mix is wet:
- Stop watering. Empty any saucer or outer pot. UF/IFAS says never to let aloe sit in water.
- Slide the plant out and look at the roots. Firm roots are healthy. Dark, soft roots are rotting.
- If the roots are mostly firm, let the mix dry out completely before watering again. Iowa State notes that plants sometimes recover from root rot when allowed to dry out.
- If the mix is fine and organic and stays wet, repot. Iowa State advises a sharp-draining mix. Penn State suggests one part potting soil, one part sand and one part perlite or lava rock.
- Use a pot with drainage holes. NC State recommends several holes and says clay is best. UF/IFAS warns against a pot more than two sizes bigger, which can hold too much moisture.
- If the rot is advanced, Iowa State suggests propagating healthy segments or discarding the plant. Penn State notes that offsets (pups) can be removed and potted on their own; see our aloe propagation guide.
If leaves are wrinkled and the mix is dry: water thoroughly. UF/IFAS advises watering well once the top 2.5 cm (1 in) of mix is dry, then letting it drain.
If one bottom leaf is drying: remove it once it is fully dry. Iowa State suggests simply taking it off.
A yellow leaf does not turn green again. Judge recovery by firm, green new leaves from the center.
Prevention
- Water by the mix, not the calendar. Penn State advises watering thoroughly when the surface is dry in spring and summer.
- Water much less in winter. Penn State suggests keeping the mix barely moist, just enough that the leaves do not shrivel. NC State also advises watering less in winter.
- Move the plant into brighter light in stages, as UF/IFAS advises.
The yellow sap inside a cut leaf
Yes, aloe vera has yellow latex. A toxicology review by Guo and Mei of FDA’s National Center for Toxicological Research (PMID 26986231) describes tubules in the leaf’s vascular bundles that store and carry a bitter yellow latex along the leaf margin. Penn State says it comes from a layer of cells just beneath the outer skin.
It is normal and does not mean the leaf is sick. It is not the clear gel, though. NC State lists skin irritation from the latex, and lists abdominal cramping and diarrhea if aloe is eaten. The ASPCA lists aloe as toxic to dogs and cats. Wash the sap off your skin and keep cut leaves away from pets.
Our article on aloe latex explains how it differs from the gel. Our gel harvesting guide shows how to drain the latex before using the gel.
Related guides
Other aloe vera problems we cover: brown tips, repotting stress, mealybugs. The aloe vera hub lists them all.
References
- Iowa State University Extension and Outreach: Common Problems and Issues of Succulents
- NC State Extension Gardener Plant Toolbox: Aloe vera
- UF/IFAS Extension, Gardening Solutions: Aloe Vera
- Penn State Extension: Aloe, a Hardy Houseplant
- Guo X, Mei N. Aloe vera: A review of toxicity and adverse clinical effects (2016), PMID 26986231
- ASPCA Animal Poison Control Center: Aloe
How this guide was put together: Iowa State University Extension, NC State Extension, UF/IFAS Extension and Penn State Extension guidance, a toxicology review from FDA's National Center for Toxicological Research, and the ASPCA.