How Long Should I Leave a Grow Light On? (For Every Type of Indoor Plant)
Last updated: 30.05.2026. If you’ve just bought your first grow light and you’re trying to figure out how many hours per day to run it — here’s the simple answer, broken down by what you’re actually growing. Most indoor plants: 12–16 hours per day.Herbs and leafy greens: 14–16 hours per day.Seedlings: 14–18 hours per day.Flowering…