Blackouts and Plant Growth?

[FSEMTB2]

How come plants seem to grow like crazy when you do a 4-5 day blackout?

 

[7Enigma]

Because they are trying to grow towards the surface where they will hopefully find light. Almost all of us that have done several day blackouts have the same WOW! reaction when we take off the covers. Just like in tanks with lower light than ground cover plants need where they grow towards the surface rather than across the substrate, in blackout conditions the plants feel they need to grow towards the surface to get to the light.

And if I remember correctly from a while ago, they don't actually increase in biomass (weight), they just elongate by burning stored sugar.

 

[Purrbox]

Yeah, what 7Enigma said. During the day plants build biomass, but at night they use the stored energy to physically stretch. So the actual growth is during the day, but what looks like growth and is visible to us happens during the night.

 

[theotheragentm]

Do the plants become weaker when they stretch themselves out like that? Do they regain their mass once light is added again?

 

[Purrbox]

I'd say that a lot depends on how healthy the plants are to begin with. As long as they have enough energy stored away and don't exhaust their reserves stretching, it would be unlikely to do more than possibly temporarily weaken them. If on the other hand the plants aren't very healthy to begin, don't have much in the way of energy reserves, and are exposed to prolonged dark periods they could die as a result. Most people report that the majority of their plants do fine, but often one or two species suffer greatly and/or don't make it. These are usually the plants that are in poor health to begin with and/or are more demanding or delicate.

I think that in a lot of ways it's similar to when you get really sick for a few days and don't eat much of anything. You may loose a bit of weight and are probably going to be a bit weak after you start getting better, but as soon as you start eating again you quickly return to your former health and strength.

 

[rkilling1]

Here is a thread that explains what 7Enigma and Joy have already said:

http://www.aquariumadvice.com/viewtopic.php?p=740962