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Author Topic: Indoor citrus, Lighting length time and warmth ??  (Read 1425 times)

SoCal2warm

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Re: Indoor citrus, Lighting length time and warmth ??
« Reply #25 on: March 11, 2020, 03:49:10 AM »
Also efficiency of the light probably does not matter in practice, since any inefficiency will turn into a little extra heat.
(inefficient lighting is pretty much no less efficient than an electric heater at producing heat. electric conversion to heat is one of the few things that is nearly 100% efficient)

However, heat can lead to faster water loss.

SeaWalnut

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Re: Indoor citrus, Lighting length time and warmth ??
« Reply #26 on: March 11, 2020, 05:26:40 AM »
Plants ate green so they reflect the green light.Basically they only reflect the green color of the white light that is made of all the colors of the spectrum.
NASA studyed well growing plants with red and blue light and the blue its like 10% at max ,used.
Corals grow their zooxanthelae mostly with blue light because the red color its filtered by the water.The deeper it gets less red .
Also the deep water fish are mainly red because that helps them to camouflage in the darkness.
Deep water jellyfish that are transparent ,have at least the stomack red to camouflage the prey they eat.

SoCal2warm

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Re: Indoor citrus, Lighting length time and warmth ??
« Reply #27 on: March 11, 2020, 03:51:59 PM »
My theory on why plants are green is because maximum photosynthesis takes place early in the morning or late in the afternoon, or in overcast weather, when there are cooler temperatures to avoid water loss. The plant closes its pores more in the heat of the middle of the day. Cooler temperatures correlate to a higher percentage of red or blue light. Also the plant does not need higher conversion efficiency when there is more light, which correlates to higher ratio of green wavelengths in the middle of a sunny day. Early in the morning, the sun is at more of an angle, passes through more layer of atmosphere, so the spectrum is shifted to longer more red wavelengths.

Millet

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Re: Indoor citrus, Lighting length time and warmth ??
« Reply #28 on: March 11, 2020, 10:53:15 PM »
Photosynthesis begins at low intensities of light and increases till it is maximum at the brightest time of the day. The amount of light required varies for different plants. Photosynthesis uses maximum up to 1.5 % light in the process and so light is generally not a limiting factor at high intensity. However, the light becomes a limiting factor in low intensity because no matter how much water or CO2 is present, without light photosynthesis cannot occur. At high intensities, the temperature of the plant increases which leads to increased transpiration in the plant. This leads to the closing of the stomata which leads to a reduced CO2 intake. Thus, leading to a reduction and finally stoppage of photosynthesis. Therefore, excessive light inhibits photosynthesis.  (Taken from Topper)

SoCal2warm

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Re: Indoor citrus, Lighting length time and warmth ??
« Reply #29 on: March 12, 2020, 12:51:15 AM »
Also to mention, water loss will be much higher from heating caused by light, or heating from a heat mat, than heat that is even and circulating within a plant enclosure.
If the plant is a warmer temperature than the surrounding air, water loss will occur. This is the same principle that freeze drying works through.
Cold air holds less water, so when that air passes over a warm surface, heat is transferred to the air, and along with that heat moisture is carried away because the warmer air can now hold more water vapor.
However, if the warm air is relatively saturated with humidity, and it is not cooler than the temperature of the plant, than it will not carry away much moisture or have a drying effect.

A potential disadvantage of excessive light is that it is effectively beaming heat energy directly onto the leaves. This can put drought stress on a plant.
This is a particular consideration because plants growing in containers have smaller root systems without as much access to water.

 

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