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I just wondered if one could grow plants faster, if they were exposed to sunlight-like light all the time.

In a similar question which is not the same, I could confirm that plants have different processes going on at day and at light. However, it didn't answer the question about the consequences of permanent exposal to sunlight.

However, I don't understand what would happen if there was light all the time. What would happen to different plants if they are exposed to "sunlight" 24/7?

(Similarly: What is the "optimal" amount of sunlight time different plants have? Is it basically what is common in the environments they typically grow in?)

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    $\begingroup$ Possible duplicate of Do plants need sleep? $\endgroup$ – tyersome Nov 4 '19 at 20:39
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    $\begingroup$ Look into crop growing in Alaska, Scandinavia, and other places where there is nearly continuous sunlight in summer. $\endgroup$ – jamesqf Nov 5 '19 at 4:30
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This review (from 2011)1 states that it depends on the plant species and cultivar.

Some continuous light (CL)-grown photosynthetic organisms show increased productivity. However, CL also induces negative effects in several plant species. The most visible CL-induced negative effects are leaf chlorosis and necrosis. CL also lowers photosynthetic parameters ... The CL-sensitive species include eggplant, geranium, some onion species (Allium fistulosum), peanut, some cultivars of potato, tomato, and even lichens (Xanthoria parietina) and mosses (Pleurozium schreberi and Ceratodon purpureous).

Among the plants that have better yields under continuous light are lettuce, roses, some potato cultivars, some algae.

The reasons why some plants can be damaged under continuous light aren't completely clear (at least they weren't in 2011). One of the problems is carbon imbalance. Leaves produce too much sucrose and other organs such as roots are not able to process it fast enough. This leads to high sugar concentrations and can cause leaf senescence. Continuous photosynthesis also results in more photo-oxidative damage and plants that better detoxify reactive oxygen species have less negative effects from continuous light.

So look for research on the particular species you want to grow or just experiment with different light conditions.


1. Velez-Ramirez, A.I., van Ieperen, W., Vreugdenhil, D. and Millenaar, F.F. 2011. Plants under continuous light. Trends in plant science, 16(6):310-318.

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  • $\begingroup$ Plants - like essentially eukaroytic &/ phototrophic organisms - have circadian clocks, regulating a bunch of cellular processes including the 'light' and 'dark' cycles of photosynthesis. Circadian systems can control a lot different things so disrupting them can have all sorts of effects - which is probably also why some plant species are affected in different ways than others. $\endgroup$ – Nicolai Nov 6 '19 at 15:51

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