Severe light shortage

What's happening

Croton's vivid reds, oranges, and yellows come from pigments it only produces in strong light; in dim conditions it reverts to plain green to capture what little light there is. When the shortage is severe, the plant also stretches its stems toward the nearest window, spacing leaves far apart on long, bare growth as it reaches for more light.

How to fix it

Move the plant to the brightest spot you have — croton thrives in several hours of direct sun a day, especially from an east, south, or west window. If your home simply doesn't get that, a full-spectrum grow light is the most reliable fix and is often the only way to bring the color back indoors. New growth will emerge more colorful and compact in stronger light, though already-greened leaves usually stay green. You can prune back the leggiest stems to encourage fuller, bushier growth once it's well-lit.

This is general guidance based on common symptoms; individual plants vary.