Yellow leaves are your plant's way of writing you a note. Here's how to read it.
Lower leaves only, plant otherwise happy
Usually just age. Old leaves retire so the plant can put energy into new growth. Snip them off and move on guilt-free.
Yellow with damp, heavy soil
This is the most common one: too much water. Roots need air as much as moisture. Let the soil dry out more between waterings.
Pale yellow all over, slow growth
Often hungry — usually nitrogen. A balanced liquid feed every couple of weeks during the growing season perks things up.
Yellow with green veins
A little iron shortage, common in alkaline soil. An iron tonic (chelated iron) from the garden centre usually fixes it within weeks.