Yes greenhouse requires grow light but not all greenhouses require grow lights or artificial lights or supplementary lights.
It’s mainly depends on DLI, climate conditions, Photoperiod and commercial value of crop.
• DLI – If available DLI is less than desired DLI then we have to give supplementary light. • Climatic conditions – During rainy time or cloudy condition plants doesn’t get sufficient sunlight so we can give artificial lights. • Photoperiod – Long day plant require 16-18 hours sunlight but most of sunlight available max 12 hours so in such cases we can give artificial lights. • Commercial value of crop – Grow lights plays important role on both capital cost and operating cost so commercial value and ROI calculation plays important role while selecting artificial lighting.
How to calculate required supplementary light inside green house.
1. Need to calculate DLI (Daily Light integral) inside the green house 2. Decide best DLI for growth of plant. ( time when plant gives best result) 3. Once we decided best DLI for plant 4. Supplementary DLI= Best DLI – Current DLI 5. Once we get the supplementary DLI, we can calculate supplementary light requirement. 6. According to supplementary light, will design LED light source and supporting system.