In general, leaves that turn yellow indicate one of the following:
- Excess moisture due to poorly drained soil, excess watering or excess rainfall.
- Lack of fertilizer; especially nitrogen.Only water if the soil is dry and not just the mulch. It helps to allow the soil to dry slightly between irrigations and force the plants to work and make their roots stronger. SunPatiens can tolerate some wilt stress and forcing them to work a bit more promotes a stronger root system and overall more vibrant plant.
- Try feeding them with fertilizer weekly with Miracle Gro at the ½ or 1/3 rate. Feeding more often at a weaker strength works better in some situations.
- Keep mulch away from the plant stems to avoid stem rot.