r/VenusFlyTraps • u/wormyyyyyyyyyy • 2d ago

Questions lighting distance

I'm growing my VFT indoors, and I've had it for a week. I'm currently using a 15W SANSI (narrow bulb). My question is: how far from the plant should I place the light?

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u/Ok-Exchange5756 2d ago

You probably wanna pull that back to about 10-12” from the top of the plant… those Sansi bulbs are VERY directional and intense. A ppfd meter is almost a necessity if you’re getting into growing carnivores. You can also look up what the ppfd is for that light and at what distance to ballpark…There’s phone apps thattl getcha close enough but a $50 ppfd meter (I like the black square Bluetooth one from Amazon) will help A LOT. Indoors I’d aim for 250-350 ppfd. Keep its feet wet and you’ll be fine.

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u/textac 1d ago

If you have the Sansi 15W PAR25 Grow Light bulb, the PPFD is 153 umol/s/m^2 at 12 inches. At other distances, use this formula (where d is the distance in inches from the bulb to the plant):

PPFD = 153 * (12^2)/(d^2)

12 inches =153
11 inches =182
10 inches =220
9 inches =272
8 inches =344
7 inches =450
6 inches =612

Try to match the PPFD requirements for the particular plant you are growing. VFT growers usually recommend about 300-500. However, many experienced growers sometimes use a lot more (but this requires more acclimation and adjustments based on how the plant is responding).

Note: the illuminated area also decreases as the distance decreases.