I recently bought some orchids. The Phalaenopsis requires 1500 foot candles of light. The Dendrobium requires 2000 foot candles. The ascocentrum requires 4000 foot candles.

When I looked into purchasing lights for these orchids, the lights are rated in lumens. I found that a combination of four 60 Watt fluorescent bulbs are giving out 20,000 lumens of light. And a combination of four 40 Watt fluorescent bulbs are giving out 14,000 lumens.

How do I convert the foot candles to lumens? I looked up some web sites, but they are very confusing. Some have lumens per square feet and other have lumens per square meter. Which one is the correct one?

Can some one help me out with this. So that I can buy the correct lights. Thank you.

Ramesh.

You will have to go some to reach 4,000fc using fluorescent tubes, possibly with high output T5s on very small plants, probably a little easier with compact fluorescents.