Growing plants with lasers

[Benm]

Some peppers might require warmer temperatures to thrive in general. It depends on the exact cultivar though, so experimenting with fairly random seeds will yield fairly random results.

70 fahrenheit should be enough for most though, as long as it doesn't get colder than that at night. Most peppers will grow in non tropical areas during summer, they do pretty well in western europe even outside, but the growing season is rather short so your timing has to be pretty good to get a decent yield. The most common thing to do is to sprout them indoors in early spring, and transfer them outdoors somewhere in may when there is little or no chance of freezing weather at night.

 

[Bionic-Badger]

Many cheap grow lights are built using 635nm LEDs, instead of the more expensive 660nm LEDs, that are meant for lighting, but aren't so suited for chlorophyll (A) absorption. The ~655nm red lasers might do a good job though. If you were doing a growing operation, the power costs might justify the initial cost of using lasers for greater efficiency, assuming they last as long and you're very patient.

 

[Benm]

I'm not really sure that 650-660 nm leds would be more expensive (to produce), but they are less commonly available nowadays.

The difference is not that significant though: Plants will capture a 660 or 635 nm photon well, but the latter has a few percent more energy that is not used by the plant. This is a loss, but equates to the voltage difference between a 660 and 635 nm led given equal quantum efficiency.

And when looking at that aspect, red laser diodes are pretty good compared to red led's. They usually produce many more photons per mA compared to led's, and the wavelength is on the 650 nm sweetspot as well.

With current technology a combination of red lasers with blue leds might be the best performing system overall.

 

[Alien Laser]

hmm i was thinking it must be possible to grow planets using a laser like 2 days ago hehehe
:topic:

 

[thebigfotos]

Hello All,

I am new to the group. Great discussion. I work on laser bio-stimulation of plants for my PhD project. I am at Texas Tech right now. I am using 640 and 473nm, 25mW diodes. The beam is pretty sharp, 2 mm for red and 5 mm for blue. It has been 2 years I am working to increase the root growth using lasers, and by far what I feel is I am giving too much energy at the point of exposure. But the interesting fact is, the plant generate relatively more biomass when exposed to laser. I am not continously exposing them for long time. I am trying to see if one time exposure can create a big difference in the germination and growth of plants or not.

Any idea, help, and more discussion is much appreciated.

Let us keep this open and going.

Cheers

 

[paul1598419]

This thread is over a 22 months old and only showed up because of spam. We try not to reopen these old threads as they muck the place up, but I understand your interest.

 

[Benm]

It doesn't really matter that it is an old thread here though, plant's have not evolved that much in a year or two

It makes me kind of curious about how this whole thing developed over time.

Research into growing plants under specific wavelengths is still going on, and probably will be for quite some time. Growing plants under only artificial light has been a mostly underground (i.e. pot) thing until fairly recently.

Interestingly companies are still working on it, including on what effect the light mix has on produce quality for various vegetables and fruits. Apparently the light spectrum not only influences growth rate of produce, but also things like flavour of veg and fruit produced - quite interesting!

 

[AMooMooCow]

Hello All,

I am new to the group. Great discussion. I work on laser bio-stimulation of plants for my PhD project. I am at Texas Tech right now. I am using 640 and 473nm, 25mW diodes. The beam is pretty sharp, 2 mm for red and 5 mm for blue. It has been 2 years I am working to increase the root growth using lasers, and by far what I feel is I am giving too much energy at the point of exposure. But the interesting fact is, the plant generate relatively more biomass when exposed to laser. I am not continously exposing them for long time. I am trying to see if one time exposure can create a big difference in the germination and growth of plants or not.

Any idea, help, and more discussion is much appreciated.

Let us keep this open and going.

Cheers

Personally I have never been burned by a 25mw laser, and a plant is way more transparent. Temperature increase might be useful to measure if you can get your hands on one of those $150 thermal imagers for your phone, but only if it's part of any equations you might generate. Of course temperature will affect rates, but you might be the first one to investigate local growth and healing of root systems. You probably know that plants have evolved to work well with 1000W/m^2 sunlight. The areas of your beams are (pi/4)*d^2, which is red: (3.14E-6)m^2 blue: (19.6E-6)m^2, so the powers of which are red:7962W/m^2 and blue:1276W/m^2.

Also, remember that the wavelength distribution of the spectrum of the sun gives that you won't have 1000W/m^2 of red or blue light, but less than that, which might be worth investigating as an argument to show that plants can grow more efficiently than with a whole kilowatt in a square meter. You should define a deviation for the limits of useful red light and blue light, then integrate the distributions of each with respect to wavelength, and that should help you find actual solar power of both wavelengths, which may or may not be helpful in your studies.

So, are these laser pointers or laser modules that you can adjust the focus of by twisting the lens?

If you wanna have a deeper conversation, you might want to PM me in case this thread starts to bump to the top of the forum too much

 

[Cyparagon]

Any idea, help, and more discussion is much appreciated.

Have a control group, have LARGE sample sizes, have a group exposed to different colors, and have a group exposed to LED light instead of laser light, as people often assume the mechanism of action is the coherence, when that has not been established.