Science Fair Project: Light Color Effects on Sunflower Growth

I'm doing a science fair project testing which color of light causes sunflower seeds to grow best. I need research on sunflower seed growth—can you help?

Guidance for Your Project

Sunflower seeds actually germinate in darkness, but once they sprout and bloom, the flower heads track the sun (heliotropism). This suggests blue and red light spectra are important for different growth stages. Red light (around 660nm) promotes flowering and fruiting in many plants—commercial tomato growers even use red plastic mulch to reflect red light onto plants. For your experiment, try comparing full-spectrum white light, blue light (400-500nm), and red light (600-700nm). Search "light spectrum effects on sunflower growth" or "photomorphogenesis in Helianthus annuus" for scientific sources. NASA and university horticulture departments have excellent research on this topic.