Alocasia leaves turn yellow most often because the compost is staying too wet. Overwatering is the usual culprit, but a single yellow leaf can also be normal ageing, a response to low light, or a sign the plant is trying to go dormant. The trick is reading which one you are looking at.
Here is how to tell the causes of yellow Alocasia leaves apart, and what to do about each.
Overwatering & Soggy Compost
If several lower leaves yellow at once and the compost is damp days after watering, the roots are the problem. Alocasia are thirsty when in growth, but they hate sitting wet, and soggy compost quickly leads to root rot. Check the top few centimetres before every water, and only water when they feel dry. If the pot is heavy and the mix stays claggy, repot into something more open like our Alocasia Premium Potting Mix.
Normal Leaf Drop & Dormancy
Alocasia keep a small number of leaves at a time. When a new leaf unfurls, an old one often yellows and drops. One older leaf slowly going yellow while a fresh one appears is nothing to worry about. In autumn and winter, especially in a cool room, an Alocasia may shed most or all of its leaves and go dormant, surviving as a corm underground. If yours is doing this as the days shorten, ease right off the watering and wait; it usually returns in spring. This is the same behaviour behind an Alocasia that suddenly droops.
Underwatering, Light & Feeding
Yellowing is not always about too much water. If the compost has dried out hard and the leaves are yellowing and crisping at once, the plant is too dry. Water thoroughly and let the excess drain. Too little light also drains colour: Alocasia want bright, indirect light, and in a dim corner older leaves fade and yellow. Move it somewhere brighter, but out of harsh midday sun. A hungry plant in summer can yellow between the veins too, so feed with a balanced houseplant food through the growing season.
What to Do About Yellowing Alocasia Leaves?
Work through the problem in order. Start by checking the compost. If it is still wet, hold off watering and check the roots for any signs of damage. If the compost is completely dry, give the plant a thorough watering.
Next, look at which leaves are affected. Yellowing on the oldest, lowest leaves is often a natural part of the plant’s growth cycle, although it can also be a sign of overwatering. If newer leaves are turning yellow, this may point to a more serious issue with the roots, light levels or feeding.
Before making any drastic changes, consider the plant’s light levels and the time of year. Alocasias naturally slow down during the cooler, darker months and may shed older leaves as they prepare for dormancy.
Once a leaf has turned fully yellow, it will not turn green again. We suggest allowing the plant to fully die back rather than removing leaves too early, as the plant can continue to draw nutrients from them while they are still green. Once the leaf has completely died back, cut it away at the base using clean, sharp scissors and focus on providing the right conditions for healthy new growth.
Yellow leaves are one of the most common houseplant worries, and the causes are similar across species. Our general guide to why houseplant leaves turn yellow covers the pattern across your whole collection.