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CFLs as Grow Lights

10 years ago

I bought six 20W daylight CFL and am keeping it each one over one 4" pot - having 3 seedlings. The CFLs are like 1-2" above the seedlings. Using a light meter I measured the approx. foot candles being hit around the top of the seedling and it seemed to be around 2500-3000 fc. and I could sense that they generate some heat around near to the bulbs. The temperatures reading near the bulbs are 5-7F higher than the normal room temperatures. I was reading on one of the FAQs on GW that seedling require 750 fc and also it is advised not to expose them to direct sunlight (or even windows getting direct sunlight). Now I was thinking if I should maintain this distance or increase it so that the foot-candles reading is more closer to 750 fc? Is the 3000 fc reading too intense for the seedlings?

Would highly appreciate your inputs.

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