Plumeria seedlings prefer bright, indirect light, especially in their early stages of growth. This preference for light aligns with their natural tropical habitat, where they receive ample sunlight filtered through other vegetation. Here are key points to consider regarding light for Plumeria seedlings:

1. Bright, Indirect Sunlight: In their initial growth stages, Plumeria seedlings thrive in bright but indirect light. Direct sunlight can be too intense for young seedlings, potentially causing leaf burn.
2. Gradual Sun Exposure: As Plumeria seedlings mature and strengthen, they can tolerate and eventually require more direct sunlight. It’s important to gradually acclimate them to direct sun, starting with a few hours of morning sunlight, which is gentler, and gradually increasing their exposure.
3. Indoor Lighting: If growing Plumeria seedlings indoors, place them near a south-facing window where they’ll receive plenty of light. If natural light is insufficient, consider supplementing with grow lights. These lights should be placed a few inches above the seedlings and left on for about 12-14 hours per day to mimic natural sunlight.
4. Outdoor Lighting: When moving seedlings outdoors, initially place them in a location where they’ll receive filtered sunlight or partial shade, especially during the hottest part of the day. Over time, as they acclimate, you can move them to a sunnier spot.
5. Seasonal Adjustments: Be mindful of the changing intensity of sunlight with the seasons. In summer, when the sun is more intense, you may need to provide some afternoon shade, especially in hotter climates.
6. Avoiding Deep Shade: While direct sunlight can be harmful to young seedlings, too little light is also detrimental. Plumeria seedlings grown in deep shade tend to become leggy and weak and may not develop properly.
7. Monitoring Plant Response: Observe your Plumeria seedlings’ response to light. If they appear to be stretching towards the light or becoming spindly, they likely need more light. Conversely, if the leaves show signs of burning or drying out, they may be getting too much direct sun.

Providing the right lighting conditions is crucial for the healthy growth of Plumeria seedlings. With proper light, these plants can develop strong stems and lush foliage, setting a solid foundation for future flowering.