Filtered Light For Plant Growth

I have a hunch that using light filters to modify the spectrum of standard white light lamps, like LED or fluorescent, may be beneficial. I base that on this article, in which the authors filtered UV, green, or both from sunlight and observed improved plant growth.

So to see for myself I ordered some "minus green" filters, Rosco brand. I'll start the experiment in a few days. Look at that tomato at the right in the second row, which had both UV-A and green filtered out. That's a mighty fine looking tomato plant compared to the one grown in unfiltered white light on the left.

Gee, where are all those people who were saying how ridiculous my light filtering idea was? That's what I thought.

Looks like an interesting experiment, pleaase keep us posted.

Subbed. Interested in the outcome.

Thanks for doing this!

very interesting. how old is that data too doesn't look to new what have we miss lol

Gingerbee said:

very interesting. how old is that data too doesn't look to new what have we miss lol

Click to expand...

Looks like the article is from the 1960s, I don't know. Yeah, it's strange nobody else ever picked up that line of research. Seems like it would boost greenhouse yields considerably. I know they do use UV filtering coverings but I haven't seen anything about filtering out green.

Intrested in result comparative

Filters arrived. Operation green screen commences. Not a controlled experiment or anything, just me improving my lighting system and seeing if I find any noticeable improvement. Has to be an improvement over normal dimming, aside from power usage. I'm only dimming down the bad part. I'll see if I get a 30-50% increase in dry weight like they did with some other plants. That would be a good trick huh, more yield by cutting light out?

It was easy to install. I just cut each sheet in quarters and scotch taped the corners under the circular COB array, about 8" diameter. No sign of heat stress to the sheet. The light now looks sort of a warm white, not purple or magenta. It's a lot easier on the eyes to look at the plants now because not as much green light is bouncing off them into my eyes. I put some under CFLs in a small veg area too. I like the improved spectrum, worth the price to me, $40 with shipping for two 24"x21" sheets. BTW, here's another good article about the effects of green light.

Here's how it looks in there now. This is Bubble Bomb. No blurple here. It's Hawaiian sunset. Give your plants a vacation from dull white LED light today, with Rosco brand filters.



Here's how it looked before. Light source is 4100k CXB, a couple days before the above pic. Look how green/yellow it was.