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Measuring Light

Posted by lucky123 7 (My Page) on
Sat, May 3, 14 at 14:12

I know, I should buy a meter but
Meanwhile I want to get a rough idea of what light intensity I have in an area. I tried the shadow on white paper. That works somewhat.

However, I placed a table lamp next to the plants. I turned on a 60 watt incandescent and it doen't increase the light/brightness in that area.

I put a 100 watt incandescent light in the same lamp and it does increase light/brightness.

For African violets, can I translate that test into some meaningful measure? Enough? Not enough?

I can use the plants as light meters. If they sunburn, too much light. If they get leggy, too little but that seems a very inefficient and slow way to go about it.

Follow-Up Postings:

RE: Measuring Light

You could use the light meter in a camera to get a relative lumens comparison. Would be a cheap & effective way to do it, if you throw the camera on a tripod and check the f-stop or shutter speed with different lights

Keep in mind that measuring light brightness by eye or camera is a lumens measurement which does not directly translate to photosynthetic efficiency. For true horticultural evaluation you would need at least a PAR meter.

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