# How much light do my herbs need indoors in the winter?
**URL:** https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875
**Category:** Factual Questions
**Created:** [October 16, 2024, 3:17pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875 "2024-10-16T15:17:44Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@LivingGhost371](https://boards.straightdope.com/u/LivingGhost371)
#### Post date: [October 16, 2024, 3:17pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/1 "2024-10-16T15:17:44Z")
Using “herbs” in the normal sense of the work- hot peppers, mint, lavender, etc. The past couple of years I’ve used a 150 watt 5000K induction lamp with disappointing results. Everything but the peppers died out and the peppers basically went dormant until I brought them back outside in the spring. This fall I bought a 100 watt broad spectrum LED light.
What I’m having difficulty finding is **“how much light in foot-candles do my plants actually want, and for how long”** to make sure I’m doing it right. Looking online it seems most growers use different measurements like lumens per square foot, or units called PPFDs and DLI. FWIW I found a list of PPFDs and DLI for various plants, but have no idea how to convert them to foot-candles that I can measure.
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### Author:  [@Jebbilene](https://boards.straightdope.com/u/Jebbilene)
#### Post date: [October 16, 2024, 11:04pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/2 "2024-10-16T23:04:01Z")
1 foot-candle = 1 lumen per square foot, if that helps.
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### Author:  [@markn\_1](https://boards.straightdope.com/u/markn_1)
#### Post date: [October 17, 2024, 12:03am UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/3 "2024-10-17T00:03:47Z")
Here are some pages that discusses conversion between PPFD and foot-candles. An exact conversion depends on the spectrum of the light source, but there are approximations used in these pages.
> **[Convert Lux to PPFD - Online Calculator | Waveform Lighting](https://www.waveformlighting.com/horticulture/convert-lux-to-ppfd-online-calculator)**
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> Online calculator to convert illuminance (lux) to PPFD (micromoles per second per meter squared).
> **[LUX to PPFD & PPFD to LUX Conversion Calculator from Nexsel](https://www.nexsel.tech/convert-lux-to-ppdf.php)**
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> LUX to PPFD and PPFD to LUX precise conversions using our calculator. Get the exact values! Convert LUX to PPFD: Online Calculator for Plant Lighting
[https://www.apogeeinstruments.com/conversion-ppfd-to-foot-candles/](https://www.apogeeinstruments.com/conversion-ppfd-to-foot-candles/)
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### Author:  [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)
#### Post date: [October 17, 2024, 12:51am UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/4 "2024-10-17T00:51:15Z")
Success indoors with herbs over the winter depends not just on adequate lighting, but also on freely draining soil and cool-ish temps, with a preferable drop-off to upper 50s or so at night.
I’ve had OK results with basil and sweet pepper under a two-tube shoplight-type LED fixture. They don’t seem to need super-strong light unless one is going for heavy cropping.
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### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [October 17, 2024, 1:35pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/5 "2024-10-17T13:35:18Z")
I think you’re going to need a LOT more light. A single puny 100 watt LED bulb isn’t going to do the job, unless it _draws_ 100 watts, not just puts out the equivalent of a 100w incandescent bulb.
We’ve got a couple of grow lights for starting seeds indoors in January, and one’s a 1800w LED contraption, and the other used a 200w CFL bulb (a HUGE thing with a Mogul base that draws 200w) like the kind they use to illuminate parking lots. Now we’ve got a 200w “corn” full-spectrum LED bulb in it- these are the replacements for metal halide lights for industrial purposes.
Something like this would be a good place to start:
[Amazon.com: MARS HYDRO RP2000 Led Grow Light, Patented Reflector Deeper Penetration and Dimmable Full Spectrum Grow Light for Indoor Plants Veg Bloom for 3x3 Tent : Patio, Lawn & Garden](https://www.amazon.com/MARS-HYDRO-Patented-Reflector-Penetration/dp/B0CKW1J5CL?ref_=ast_sto_dp&th=1)
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### Author:  [@LivingGhost371](https://boards.straightdope.com/u/LivingGhost371)
#### Post date: [October 17, 2024, 6:31pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/6 "2024-10-17T18:31:11Z")
This is the one I have,
> **[Amazon.com : VIPARSPECTRA P1000 LED Grow Light for Seed Starting Vegetables...](https://www.amazon.com/VIPARSPECTRA-Upgraded-Spectrum-Dimmable-Hydroponic/dp/B083JVXHF6)**
>
> Amazon.com : VIPARSPECTRA P1000 LED Grow Light for Seed Starting Vegetables Bloom, Dimmable Plant Lights Dimming Daisy Chain Grow Lights for Indoor Plants Full Spectrum for 3x3/2x2 Grow Tent : Patio, Lawn & Garden
Grow area is 4 X 3 and light is currrently about 4.5 feet high, could be raised to 5 foot or lowered to whatever.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [October 17, 2024, 10:31pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/7 "2024-10-17T22:31:15Z")
> [@LivingGhost371](#):
>
> This fall I bought a 100 watt broad spectrum LED light.
“Broad spectrum” probably just means that it has a lot of different wavelengths within the visible range. If it doesn’t say “ultraviolet”, then it almost certainly doesn’t include ultraviolet, since ultraviolet is more difficult to get from LEDs than visible colors. And plants need at least some ultraviolet.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [October 18, 2024, 3:36pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/8 "2024-10-18T15:36:42Z")
I haven’t tried LEDs. I built one using fluorescent bulbs. Works really well.
The light fixture is a 4 foot shop light with reflector, integral power cord, and pull chain. The light can accommodate four, 4 foot (48 inch), T8 fluorescent light bulbs. Each bulb is 32 W (F32T8). Two of the bulbs have a color temperature of 3000 K, two have a color temperature of 6500 K, and I staggered them when I installed them. The light hangs from an expandable garment rack 1 using a couple chains. This is really convenient; I can easily raise the height of the bulbs as the plants grow.
[ ](https://live.staticflickr.com/65535/52647739147_7c968b4c28_z.jpg)
[ ](https://live.staticflickr.com/65535/52648671905_b7ef8bebf2_z.jpg)
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### Author:  [@bump](https://boards.straightdope.com/u/bump)
#### Post date: [October 18, 2024, 4:00pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/9 "2024-10-18T16:00:23Z")
How close are you putting it to your herbs? I’d think that light should do the trick, but it’ll need to be very close. Close as in maybe 6-8" away.
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### Author:  [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)
#### Post date: [October 18, 2024, 10:45pm UTC](https://boards.straightdope.com/t/how-much-light-do-my-herbs-need-indoors-in-the-winter/1008875/10 "2024-10-18T22:45:24Z")
Yeah, the adjustable height is key, especially when starting seedlings you want it very close or many can get “leggy” and ultimately fail or be weak. In my limited experience, Brassicas get this bad (broccoli, cauliflower, cabbage, Brussels sprouts, etc.) Also a lot of light, which this setup looks good for that.