@jerijen Remarkable! I think this is the Roses Forums takeaway: We didn’t expect the organic solar cells to outperform a conventional glass-roof greenhouse.
But we repeated the experiments multiple times with the same results and after further research and analysis, we discovered that plants don’t need as much sunlight to grow as we’d originally thought. In fact, too much sun exposure can do more harm than good, especially in climates such as California’s, where sunlight is more abundant.

"Plants don't need as much sunlight to grow as we'd originally thought. In fact, too much sun exposure can do more harm than good, especially in climates such as California's where sunlight is more abundant." Worth repeating! The more we can get the average person to understand that, then add the reflected/radiated heat issue from passive solar collecting surfaces, the sooner many of the issues growing anything can be resolved.

It appears to be a genuine study, but the press release by which it is presented seems a bit dodgy. I suppose if it can be replicated we will hear more about it.

If you don't believe that changing conditions change plant needs, consider that the Champagne region of France is becoming unsuited to growing grape for Champagne.

As are traditional coffee growing regions. New areas are opening suitable for vineyards. I never thought I'd see a Swedish wine industry but there is one.

I have a totally unrelated greenhouse story. At a Tenarky District meeting, there was a huge auction of roses. One of the most interesting was a mini with a white center and deep purple edges to the semi-double blooms. (Yes, I would love to have bought it. I cherish the memory).

Most roses were going for $12 t0 $30.

This one started in that range (Husband had gone to our room, I kept bidding along with four other folks.) One lady was really aggressive, taking it up to $110. I had shut down around fifty.

I must have looked shocked and one of the Kentucky folks leaned over and whispered to me, as way of explanation, "She has a glass greenhouse".

And I have never forgotten that.

The quote Kim highlights is from the lead author of the paper, Yepin Zhao, who is a materials scientist/engineer and, probably, doesn't have so much experience or knowledge of plants. Nowadays we know that, above certain levels of light/heat/water stress (lower than you might think), photosynthesis shuts down and plant productivity suffers, so the old idea that more sun is better for plant productivity was far too simplistic -- though probably would be a starting assumption for an engineer (or climate-denying physicists like Freeman Dyson, who blithely proclaimed that plants would LOVE global warming, what with all that CO2 and heat...one could only shake one's head).

And it is constantly demonstrated in my own yard that many so-call "full sun" plants, including roses, will actually do better with a bit less than that, in this climate at least.

Thanks for posting this interesting paper, Jeri -- lots of interesting stuff going on there, including practical use of an anti-oxidant. The journal that published it, Nature, is one of the premier scientific journals, so very likely a bona fide finding that will be interesting to see progress.

Catspa, I could not possible agree more. I think excess sun and heat are one of the major problems in my garden.

For all that "more sun" is traditionally touted, all you have to do is watch the need for adjustment it you, say, try to grow flowers in the desert.

Abriefer link

yet, Morocco has a festival of roses. Hedges made of roses.

In May, in Morocco

It appears the roses in the Morocco link are all the same variety, probably selected because they are suitable for the rose products the area makes. They look marvelous in the photo, but what do they look like the rest of the year? A very large percentage of the US rose crop is produced in Wasco, CA, with some coming from Arizona and Texas, both very likely worse "comfort climates" than Wasco. The rose crops receive significantly greater levels of water than most of us in the more arid areas are able to provide. Wasco's average temperatures are:

You can photograph gorgeous roses of hundreds of varieties during the cooler months. You won't find many you want to photograph from July through early September as they are mostly fried. I'm told by breeder friends who visit to observe their roses on trial, it's worse in the other two areas due to the higher temps.