Questions tagged [light]

Illumination, required for photosynthesis. Use this tag for all questions about the required light levels for your plants. For questions specifically about artificial lights use the [led] or [grow-lamp] tags. For questions directly about the Sun and its effects in different conditions on plants use the [sunlight] tag.

Virtually all plants require light to power the chemical reaction known as photosynthesis, to produce sugars and cellulose (exceptions include some rare orchids such as Hexalectris which are at best partially photosynthetic).

Different plants have adapted to require different amounts of light. For example, trees that grow at high latitudes are generally adapted for poor light conditions, and low latitude desert plants are adapted for high light conditions.

There can be artificial light sources like lights or beside the natural source of light: .

Use this tag for all questions about the required light levels for your plants. Use it with tag(s) specific to the plants in the question.

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Best wavelength mix for an indoor LED grow light used to grow basil

I want to grow basil. A lot of it. Unfortunately the winter is coming, and my plants won't be able to survive outdoors. Beeing an electronics engineer, i decided to DIY an indoor growbox, so that in one device i can integrate timers, sensors, an…
valerio_new
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Do herbs & spices need dark time, in order to develop flavors and nutrients?

When you grow cannabis indoor, it is considered beneficial, to have lights turned on up to 24h / day, during the "grow" phase. While this would prevent blooming, it is beneficial for building plant material. When you grow spices and herbs, such as…
user1721135
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Diagnosing yellow spots on my cactus growing under artificial light

I have owned a Mammillaria Nejapensis for the last few months which began showing unhealthy yellow spots a few weeks back and seems to be getting progressively worse. A photo of the cactus is attached. Unfortunately, my room barely gets any natural…
Roman
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How to create an indoor gardening?

I'm looking to build an indoor garden to grow lettuce, basil, maybe tomatoes etc.. I have numerous questions : Are smart gardens a viable options ? (In terms of electricity cost and harvest quantity) If not, how to I build my setup ? Which lamp is…
Rom
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What wattage of LED full spectrum grow light is best for ferns?

What wattage of LED grow light is best for ferns?
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How do grow light work?

I ordered grow lights and I never put thought into it until I got bored. But the ones I ordered (found Here) use blue and red LED's for light. What role does the Blue and Red light play for plants? Also I noticed how it has what the 2 colors do for…
Ljk2000
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Indoor durian started do dry out

I will really appreciate any help. I grow a durian tree in my livingroom and so far it's been doing great. Since september, it started sheding leaves one by one (only one at a time always goes kind of "rusty" and then falls off long before actually…
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What is light when it comes to plants?

I often see and hear people saying "this plant needs light". What is light? Just sunlight(direct and indirect) or what else? My room doesn't get a bit of sunlight, direct or indirect, but there is light. Can anyone help me with all this light…
4-K
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Upper limit on light intensity?

What is the upper limit on the light intensity for growing plants indoor in a hydroponic system? Except my electricity bill off course :-) e.g. Are 1000W HPS light per sq.m. ok, as long you can keep the heat under control? Or what happens when I…
Den Uil
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Replacement for an F15T8NDL 18" lightbulb

I am currently using an F15T8NDL 18" lightbulb for my plants in a light fixture, and would like to replace it with something much brighter. So my question is that if I add a higher powered bulb in the same fixture, will it automatically draw more…
The Nightman
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Photometry and plant growth

What unit of photometry is used to assess plant growth? Is there a catalog that lists plants and the required light exposure? I'm looking at more detailed indicators than "a lot of light" or "not too much light".
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Seeking Recommendations for a More Powerful Desk Light

I'm looking for a new grow light for my plants. The current lamp I have is too short in width, so it doesn't cover all the plants evenly. While it provides up to 20k lux at the center and based on a conversion factor of 50-70 lux per 1 µmol/m²/s of…
NLed
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Looking for an extremely shade-tolerant decorative plant

direct sun light: 0h/day indirect sunlight: quite dim, the window is 10 meters away temperature: never freezing, never too hot We tried a Ficus tree (was 50cm and in good health when moved there, survived several months) and a Pelargonium(20cm,…
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Is this grow light (GE BR30) harmful to your eyes?

Can the GE BR30 LED grow light could pose harm to one's eyes, especially if they are used in somewhere like a high bedroom shelf where the bulb itself is visible from below? Here is an image of the light's spectrum. As you can see, it goes somewhat…
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How does plant size and shape change with different levels of light?

For a plant species that is described as "full sun to full shade", what differences might I expect to see if I plant it in full sun vs full shade? If you need a specific example plant, I'm writing this because I'm trying to place an American…
Empiromancer
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