Providing Lighting 24 hours.

[Teh Teong Chian]

Hi,

 

I have an aquaponic system in my backyard and normally we would turn on the backyard lights at night for safety reason. Hence this created a 24 hours lighting for my plants and would like to know anything wrong with that?

 

thanks

[Vlad Jovanovic]

Thank you Peter. I'll be sure to check that out. I have a greenhouse so DLI's definitely interest me a bit...

I'm not so sure that AP has a low carbon footprint in many scenerios. PVC, pumps, water pumps, fans, the manufacturing of hydroton, manufactured fish food and all the problems that is associated with that...lights is just one of them. I know that low-carbon footprint, less water use are big selling points for AP and all, but probably no where near the reality, or  bio dynamic organic farming. There is a gentleman on this site trying to develop a neolithic AP model. Should be interesting to see how that works out.

Peter Shaw said:

The study was done in the 80's by a fellow grad student of mine at Cornell, (he was in grad school there, I was somewhere else), I cant even image there is anything but a footnote. Work was done on GH cut roses, which were a big deal back then.

More important and of greater significance to me is the work done on Daily Light Integrals.

Shows it not just the duration, or the intensity but the total photons during a light event.

Google that term, and be sure to look for James Faust.

What is really the question at least to me is why anyone would consider aquaponics to have a low carbon impact and, low environmental impact when they are in their garage using thousands of watts of electricity to grow some lettuce.

Matt: dont think there are any floral hormones, only in the pot growing world, where they make up plant part names and physiology to sell products. Not really a flame, too many of my students are pot growers and they believe the oddest things. But the equipment that has been developed due to the money being spent is quite impressive. They do sell something that is 99.999% water for about 25 bucks a pint, but its been "charged", and some bud magic for 75 bucks for a few oz that is standard gh fertilizer that costs $1 per pound.

The technique is called night interruption.

[TCLynx]

Hum, I wonder........

Now I know most lettuce bolting is triggered by warm weather but I wonder if "interruption"  of the night cycle could help delay bolting in lettuce even as the weather warms up here in FL?  Now that would be of interest to some people trying to grow lettuce in greenhouses year round in this climate!!!

[TCLynx]

AP in and of it's self might not save that much.  However if you think of it in terms of if the fish were being kept anyway and the garden being watered anyway, By putting the two together, you can pollute less and save more water for the same effect so it is reducing the "water footprint."  If not the Carbon Footprint.

[Vlad Jovanovic]

Hmm...IDK TC, I think with plants like letucces, or spinach... that might have the opposite effect.

Since you'd be tricking them into thinking the nights are shorter. Remember, the phyto-receptor protein(s) (this is the mechanism that tracks such things) in the plant actually measures the "dark-time" and not the "day-time".

So when we say that a plant is "long-day" plant, that same plant can be more accurately described by the term "short night" plant. (Hihi, unfortunately, it's probably much harder to block out the sun for a while during each day, than to turn the lights on at night :) ... 

[Vlad Jovanovic]

Very true. I just wish I had a way to keep and re-use all that water I used while washing my media :)

Sheesh, thats something I hope I won't be doing again any time soon. (more because of my back than because of our aquifer :) 
TCLynx said:

AP in and of it's self might not save that much.  However if you think of it in terms of if the fish were being kept anyway and the garden being watered anyway, By putting the two together, you can pollute less and save more water for the same effect so it is reducing the "water footprint."  If not the Carbon Footprint.

[TCLynx]

Well and the real problem here with lettuce is the heat seeing as lettuce can do well up North in a long cool summer with very short nights but here the heat just makes it wilt and try to seed before the heat kills it before it's time.

[Vlad Jovanovic]

Yeah I bet it's pretty tough in Florida. Then again, I think Florida weather may have some benefits too :)

A guy named William Waycott back in 1995, at the United States Department of Agriculture in Salinas, California, did a bunch of experiments that dealt with the interaction of temperature and day length on bolting (lettuce, spinach etc)...he found that plants grown in plant growth chambers under short days of eight hours of sunlight at a steady high daytime temperature of 90˚F grew to harvest maturity without bolting. Which blew me away because a lot of of what you hear/read is that temps are the main culprit. Does seem to be an interaction of the two...

Wish I had that FL weather 'problem' here ;)

[TCLynx]

There is always good with the bad.  I don't get to grow most temperate fruits here because we don't get the chilling hours but I also don't have much luck with tropical fruits since the frosts and freezes get them.  But at least I do have year round gardening even if summer is only good for sweet potatoes, peanuts, cow peas, lufa and okra.

Very interesting bit on that study with 90 degrees and the short days.  I suppose the fact that when it's 90 degrees here that usually means more like 100 out in the sun and the days are a bit longer as we get into that season.

[Matt Burns]

Nice discussion all. 

[Vlad Jovanovic]

Yeah, it seems that most things are that way...good/bad...

There's a magazine I remember seeing once called "Sub-Tropical Gardening", I think it was an Aussie thing. Might be worth checking out for some more summer-time ideas? I think asparagus was one vegetable that people were praising. Different berries and fruits too.

 

[TCLynx]

Yea, asparagus is one they generally figure we can't grow here.

[Matt Burns]

Vlad Jovanovic said:

Go for it. Seriously. I'm not trying to change what you do. All I'm saying are two things

1) 24 hour light cycles are not "harmful" (as I've already stated, not worth it, and not much benifit beyond 18h, 16, or 20 depending on the cultivar, but that still does not mean that it is harmful).

2) I do not believe that significant growth occurs during night cycles. That's it.

If you can get monsterous growth from your cannabis using a flat all 10 hour lighting schedule, that's great, and by all means continue. It still doesn't mean that they're doing most of their veg growth at night. Or that 24 hours light cycle is harmful for veg stage. 

And yes, over the last almost couple of decades now, I generally have a number of different systems running at any given time, more or less. I too like to experiment, and/or test out what I've read or been told.

Interruption of an otherwise long night by light (particularly in the red 660nm range) is a well documented and good way to prevent flowering of many plants, including cannabis. Since saying that a plant is "short day" or "long day" is a bit misleading.  "Long night" or "short night"  better describes the mechanism at work, and if you interrupt that dark, your right it totally messes them up. A little like hitting 're-set'

I don't think that we should 'try to beat nature', but I do not feel that we should mystify nature either.  

 

 

I am not saying that more light is harmful I suppose.  I was just saying that its not worth the electricity.  I hope people are not using thousands of watts for their indoor setup. T5 High Output Fluro's are around 54 Watts each.  You can do a two grow bed setup with a two 4 bulb T5 and would be under 500W of power used for 10 hours a day.  I don't use 10 hour flat time to grow monster cannabis plants. I use 12hrs on 5.5 hours off , 1 hour on, and 5.5 hours off for my vegetative room. I use 10 hours on and 14 hours off for my bloom room. Thats how I grow monster cannabis plants.  The nutrient scene is crazy.  I don't buy into all of that stuff. 10 mixes and all.......I use a simple two part solution made by Ray Cogo.