Somethin to think about...

[smurfin'herb]

Just how important is intense HID light in the last 7 days of flower...? I mean, by this point the flowers have already stopped growing anyway, at least to any noticeable extent. Most ppl do the main flush at 10-14 days before harvest, so by the last 7 days of flower the nutrients have already been removed from the medium and the plant has started using its reserves, so the plant is basically "living off of itself".

Reason i ask is... If you could take every crop out of the main flower room 7 days earlier than you ususally do, you can increase your yearly crop number by 1 extra crop/year without decreasing your "per-crop average", or buying anything except a couple floros.!!! The last 7 days You could just put the crop under a FEW floros, just enough to keep them in cycle and using their reserves and get the leaves yellow. Of course this will only work with certain grow applications, and some will be more difficult and expensive to use this method with (i.e. pots of soil handwatered vs pots of hydroton ebb n flow...think about it!!)
Hell, if your in soil/coco, you might be able to not even have to water them at all while under floros. Simply cuz the plant is ending its lifecycle and not very active, and cuz its under very low intensity light so it doesnt drink as much b/c of these facts. But huge influencing factors would be plant size/mass:gallons of media ratio, characteristics of media used, and environmental conditions. If you find you do have to water them at this phase, just turn the floros off 4-5 days after the plants were introduced under them (i.e. give em 48-72hrs of dark), and this will def make them consume less water. The goal is to have the medium bone dry when harvest time comes!

Well, what do you guys think about this?

 

[ackuric]

imo this is a very good option for those in desperate need to get some new plants going and the old ones finished up.

As you said though it may complicate things especially for some styles of grow. This would dramatically effect a perpetual harvest differently than a standard full harvest.

 

[Mc__Nugget]

I like the sound of this, it would make perpetual harvesting cycle a little faster/more, and i have also heard of people giving their plants a full 2 days of darkness at the end of the flush and them chopping them right after that, maybe you are on to something here smurfin.

 

[manwithnoname]

sounds interesting... now who's willing to give it a go?

 

[RussCargill]

Seems like a good experiment. The only reason I can see why not. The plant needs that intense light to grow. So wouldnt it still need the same light to ripen? Maybe not. Great question. The one thing that might help is keeping the heat up in the 80's even with the low light. That way the plant wont shut down all the way

 

[islandgrow]

cool idea, I guess what we need to know is how does cannabis ripen or reach maturity?

 

[purpledomgoddes]

can run lights @ 16/12...

standard 7 day calendar week is 168 hrs. 168*8(standard 8 wk fruiting cycle)=1344 total hours per 8 wk cycle.

6*16=96 hours of light per 7-day week, or 6*16*7=672 hours of light per 7 week cycle. 6*12*=72 hours of dark per week, or 6*12*7=504 hrs of dark per 7-day week. 1344-1176=168. so, can leave the plants in dark for a week (168) hrs, while have rec'd total amount of light that would have fallen on the plant in 8 weeks of 12/12 (672 hours of light).

under 16/12 light cycle, 8*96=768 total light hours, and 8*72=576 hours of dark, for a total of 1344 hours per 8 wk cycle. can be run for 7 weeks, w/ final week in total dark. prefer to run 8/16 final week though...

usually run 16/12, to 12/12, to 12/16, to 8/16... can manipulate garden multiple ways once total light/dark hours known.

w/ 16/12, in 7 weeks, will have equivalent of 8 weeks 12/12, of light. 7*12*8=672 hours of light. 6*16*7=672...

can achieve same hours of light in 7 weeks (672@16/12), as is in standard 12/12 (672@12/12)...

of course, that only adds up to 42 dark periods, so another week of darkness can be added, if desired/fruit maturity is wanting. will have acquired same amount of light though.

due to longer days than nights, usually increase night temps to facilitate distribution of energy in shorter dark period. so, negative diff is applied (higher night temps than day temps). can be as small as 1*f change - plant recognizes tiny increments in temp </>.

hope this helps. enjoy your garden!

 

[smurfin'herb]

16/12 would mean 28 hr days... wouldnt that make the plant grow slower?

 

[Observer Tom]

A friend uses half (alternating every couple hours) lights for the last 2 weeks and swears by it. Not only are the bills lower, but he claims he gets better yields than by using all the lights. i.e. still uses 12/12, but only runs every other light in the room and every couple hours swaps which lights are on or off.

With 16/12 you would give the plant 8 weeks of light in 7 weeks, but wouldn't that just make for a larger plant, not a faster plant? I mean, it's still only been 7 weeks of night cycles.

If you could speed a plant up by doing say.. 6/12 instead, there might be a benefit to smaller plants harvested every 5-6 weeks instead of 8, but I don't know if it works that way.

Either the plant would get more light and harvest at the same time, or you could give it less light and speed it up, but I don't see how you could adjust the light cycles to do both at the same time.

 

[smurfin'herb]

6/12 (18hr days) is what the harvestmasters are capable of. They say that if you add c02 to your garden you can finish crops earlier with the same yield as before adding c02. For some reason tho, i cant imagine a crop fully matured a few weeks early than ususal just because of c02. However i can see that if you add co2 you will get more yield than you were getting without it in the same amount of time. But if you pulled the 6/12 co2 crop early, maybe like @ 7weeks, you might get the same weight as you were getting without c02 and letting the runs go for 9weeks on a 12/12 schedule. Anyone ever TRULY finish 2 weeks early on a 6/12 cycle with c02?

 

[smurfin'herb]

16/12 would mean 28 hr days... wouldnt that make the plant grow slower?

Also, how would you plant even trigger into flower with 16 hours of light and 12 hrs of dark? Regardless of what crazy schedule you could use, in order for a pot plant to flower, it needs at least equal amount, or more dark hours than light hours,(with exception of autoflowerers and some sativas).

 

[smurfin'herb]

ok, bringing this back.

 

[toohighmf]

You need at least 12 hours of darkness, but the plant does not recognize photoperiods. 6 on 12 off has been done to rush crops. It works the last few weeks to save a week or 2, should you need to, but I think you really need at least 4-5 weeks of 12/12. I saw a 60 dayer done in 42 using the 6/12 method throughout. Yeild suffered 30%....

Sometimes you gotta move, or have to leave town for business or pleasure and you need to be done a week or so earlier so go 6/12 after a month to finish er up.

 

[nekoloving]

6/12 (18hr days) is what the harvestmasters are capable of. They say that if you add c02 to your garden you can finish crops earlier with the same yield as before adding c02. For some reason tho, i cant imagine a crop fully matured a few weeks early than ususal just because of c02. However i can see that if you add co2 you will get more yield than you were getting without it in the same amount of time. But if you pulled the 6/12 co2 crop early, maybe like @ 7weeks, you might get the same weight as you were getting without c02 and letting the runs go for 9weeks on a 12/12 schedule. Anyone ever TRULY finish 2 weeks early on a 6/12 cycle with c02?

You need at least 12 hours of darkness, but the plant does not recognize photoperiods. 6 on 12 off has been done to rush crops. It works the last few weeks to save a week or 2, should you need to, but I think you really need at least 4-5 weeks of 12/12. I saw a 60 dayer done in 42 using the 6/12 method throughout. Yeild suffered 30%....

Sometimes you gotta move, or have to leave town for business or pleasure and you need to be done a week or so earlier so go 6/12 after a month to finish er up.

that first post is the reason to use CO2 - there are several places and ppl here and other spots that claim CO2 gives 30-35% increase in yields if done correctly - thus offsetting the loss somewhat [30% of 100% = 30% of base whereas 30% of 70% recovery would be closer to 21% of base]

this is interesting enough to play with for sure. however why not just grow and emulate a region that grows how you like it outdoors?

why not get someone to measure light intensities at 1h intervals outside at some appropriate location. if possible get intensities of particular wavelengths of light, and then use THIS as your model indoors?

 

[mpd]

I respectfully disagree. The plants stop their dramatic growth because you have taken away a source of nutrition for the plant. I typically pump in the nutrients right up to the day I chop and get every last bit of production wrung out of the plants. I then water cure to get the chemicals out and either smoke the bud or convert it to oil or candy or hash. I'm currently on this big hard candy bing, so...

If you want to get your per plant average stats up, then keep pumping in the nutes right up to the day you chop them. If this is a commercial grow then you are automatically converting the harvest into a more convenient means of concealing it - at least the size goes way down when you make it into hash and the time spent getting product to market goes down as you have no need for a jar cure once you water cure the pot.

If this is about pure production with commercial potential clearly in mind, then you need to optimize the light (which takes a few cycles with a given clone to be sure) and nutrition and moisture. Hydro ends the debate about moisture, you are structurally eliminating it from having the same impact it does in a dirt grow, but the media can be so much more.

Since you asked...

 

[Laughing Jim]

This thread addresses an EXCELLENT question that i have always wondered about.

Indeed, after the female has been growing under 12/12 for a certain length of time, the whole 12/12 high intensity lighting routine seems to be overkill.

 

[Haps]

Having tried variations of low lighting the last week or two, by design and need, I find it worth it in quality to keep my light intense to the harvest. You can cut it the last week without too much loss.....if you are running the crop to maturity.

Plants grown till they are ready, do not feed very much in the last two weeks. If you want the best quality, including flavor, a flush is important. If you grow a ten week strain, only eight weeks, then it might feed heavy right till the last but of course, with no flush, they will taste like shit. The poster who recommended this, uses water cure to wash the crap out of his buds, with the flavor and scent washing out also, or so other folks who water cure have stated. My buds get moldy when I try water cure, so I obviously do not understand it. I only post this to balance what I consider bad advice in the thread.

 

[smurfin'herb]

Why on earth would anyone wanna stick their buds in a jar of water? Why did somebody even have to think this up one day?

 

[nekoloving]

Why on earth would anyone wanna stick their buds in a jar of water? Why did somebody even have to think this up one day?

http://www.icmag.com/ic/showthread.php?t=7482&highlight=water+cure
http://www.icmag.com/ic/showthread.php?t=22648&highlight=water+cure
http://www.icmag.com/ic/showthread.php?t=30855&highlight=water+cure
that third one... well... lol

 

[purpledomgoddes]

16/12 would mean 28 hr days... wouldnt that make the plant grow slower?

yes, 28 hr days. plants will get acclimated to it. they measure time w/ dark cycle, not light cycle. plants measure weekly averages too; relevant to light, diff, leaf temps, ambient temps, vapor pressure deficit, etc.

ran this regime last go:

from 18/6 to 12/16, went like this...

started w/ 16/12, for first 2 weeks.
then 12/12, then 12/16, then 8/16.

can manipulate in any way as long as divide 168 hr week, accordingly. temps kept @ 78-88*f day and night. by keeping temps w/ in 10* shift, preferably only 1-2*f shift, plants can focus on other environmental input(s). they just want consistency, whatever is est'd. and can be made to adapt to grow in many ways.

hope this helps. enjoy your garden!