Why does my moth orchid have yellow lower leaves?
On a moth orchid this is the lowest leaf on the plant turning a clear yellow and finally dropping. The leaves above it are firm and green, and the plant looks otherwise well.
The most likely cause, as the entry says, is an old leaf being shed. A moth orchid usually makes one or two new leaves a year, and it gives up its oldest as it goes, so one bottom leaf yellowing slowly while the others stay firm is the plant working normally. The RHS advises cutting off old leaves as they begin to fade to keep the plant looking its best.
To confirm it in a minute, count the yellow leaves and look at the roots through the pot. One bottom leaf, plump silver or green roots, and the rest of the plant firm confirm it. Then look into the crown. Tip the plant sideways: if water pours out, that is the second cause, because water left standing in the crown rots the growing point.
Two other causes are worth ruling out. Too much water kills the roots, and a plant with few live roots yellows its leaves. The entry's interval is about 7 days in the growing season and about 12 in winter, and a watering habit that has not stretched with the season can keep the bark wet. And a leaf that is yellowish or reddish all over, not just at the bottom, is a plant in too much light, as the entry notes about leaf colour.
A yellow leaf will not go green again. If it was age, nothing more needs to happen, and the plant carries on with its remaining leaves. If water was standing in the crown, the next new leaf is the proof it has been dealt with. A soft crown does not recover.
What this plant wants
| Light | Bright indirect light |
|---|---|
| Water, growing season | Every 7 days |
| Water, winter | Every 12 days |
| Humidity | High |
| Temperature | 16 to 29 °C |
| Grows in winter | No |
The fix
One bottom leaf yellowing slowly is normal. Water in the sink and tip the plant to empty the crown, because water left there rots the growing point.
Read on
- Yellow leaves at the bottom of the plant
- The same sign on any plant, with the causes in the order they are likely.
- Moth orchid care
- Light, water, feeding, repotting and the rest of the entry.
- Check it in the diagnoser
- Opens with the plant, the part and the sign already chosen.
Checked against
The figures and the advice on this page were checked against the sources below, and where they disagree the page says so.