The goal is enough light for sturdy growth without suddenly exposing tender leaves or a small root ball to conditions they have never experienced. Where the seedling grew before matters.
Move toward stronger light in stages
- For seedlings raised indoors or under shade, begin in a bright, sheltered outdoor position with gentle morning sun.
- Increase exposure gradually over roughly one to two weeks as a practical starting plan. Extend the transition during unusually hot, dry, or windy weather.
- Check for bleached or scorched patches, persistent wilting, and very hot pots. Pause the increase if injury appears; already burned tissue will not turn green again.
- Once acclimated, provide a sunny growing location. Six to eight hours is common plumeria grower guidance for flowering, but intense inland heat may call for afternoon protection.
My 2024 seedlings were outdoors in full sun from the beginning. That describes their history; it is not a reason to move shade-grown seedlings directly into harsh midday sun. Measure conditions near your plants when possible. Regional air temperatures are not measurements of plug, pot, or leaf temperature.
Follow the plant through seasonal change
In warm, bright conditions, keep supporting active growth. When growth slows and leaves fall, reduce watering and stop routine feeding. A small green seedling under adequate indoor light may still be active when a large deciduous plant beside it is resting. Judge each plant and its root-zone moisture.
Protect young seedlings well before frost. For home growers, moving them to protection when forecast nights approach 50°F (10°C) is a conservative planning trigger, not a tested injury threshold. A protected warm, bright space is more suitable for tender seedlings than cold, dark storage intended for established dormant plants.
During a genuine rest period, inspect regularly and keep pots from remaining wet. Do not impose months of complete dryness on every tiny seedling. If the plant begins shrinking, check stem firmness, root health, and medium moisture before deciding whether a small watering is needed. Resume normal watering and feeding gradually with active growth and adequate warmth and light.
References: Wisconsin Extension: Plumeria; Southern California Plumeria Society: Summer Care and Flowering; My 2024 Water-Tray Growing Account.