Mr. Nice Forums  
Home History Strains Media Web Community Medical Marijuana Contact us Auctions

Go Back   MNS Forums > Grow information > 14. Indoor

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-08-2010, 07:09 AM
Senior Member
 
Join Date: Nov 2009
Posts: 147
Default Does light spectrum change cause stress?

For example, if i have a plant thats vegging, would it upset the plant if it spent say 12 hours under a red bulb and then 6 under a blue to make up its 18 hour light cycle?
Reply With Quote
  #2  
Old 02-14-2010, 12:48 AM
Senior Member
 
Join Date: Oct 2009
Location: MNS Forums
Posts: 456
Default

Im guessing by blue you mean metal halide and for red you mean high pressure sodium.

To answer your question no, in the veg cycle it wont cause any harm it may infact beef them up a little bit.

However, if your using a HPS in flower and switch to a MH, that will mess things up a bit. I use a 1000hps and a 400hps Gavita, the 400hps burnt out and I only had a Gavita 400mh for back up. Only 5 days in the 2nd week of bloom caused a huge increase in leaf production. The plants are so leafy they don't even look like the same strain as the ones under undisturbed hps.
Reply With Quote
  #3  
Old 02-14-2010, 02:36 AM
kal el's Avatar
Member
 
Join Date: Sep 2009
Posts: 97
Default

In flower, the UV in the MH light will stress out the plant causing more trich production as well. I think this is the idea behind the dual spectrum bulbs now becoming available.
Reply With Quote
  #4  
Old 02-14-2010, 02:39 AM
L33t's Avatar
Senior Member
 
Join Date: Apr 2007
Posts: 3,544
Default

hi Greens n gertbfrow

Vegging plants will not mind even if you give em 3 different types of light during the day ( cfl , hps and natural light..)

I have noticed that during flowering adding MH lights will make em leafier too , esp if added in the early stages of flowering.

But if you have noticed it..outdoor plants are also leafier than HPS-only indoor grown ones

The calyx to leaf ratio in indoor HPS grown plants is higher that outdoors and it is due to the light spectrum , outdoor natural lighting is more like MH+HPS (and with a high MH to HPS ratio) than straight HPS lighting. Adding MH lights will also help with terpen production and may give a more deep/complex effect to the high , this is especially true for certain sativa strains.

Oldtimer1 had done some very experiments few years ago and posted the progress and results over uk420 , the test was growing several known clones under HPS-only , HPS+MH and MH-only lighting .
The results showed that although there was a decrease in yields when MH was added or MH light was used exclusively, the benefits in resin production and increased quality in the high were worth it. Not all strains seem to benefit the same and in terms of high the pure sativas showed the most improvement with MH-only light , indicas and hybrids showing little or no improvement.

MH-only lighting showed a decrease of 8% in yield compared to HPS only lighting. The plants grown under MH were a bit leafier but the flowers had greater trichome coverage and the high was more complex and psychedelic with certain clones which shows that some sativas do benefit from a mixed or MH only lighting.
Btw as advised by ot1 in may be more practical to just add or go full MH only during the last stages of flowering in order to avoid leafy plants yet benefit for the improvement of the high and possible increase in resin production as well.
__________________
cheers , Haz3
Reply With Quote
  #5  
Old 02-14-2010, 09:27 AM
Senior Member
 
Join Date: Nov 2009
Posts: 147
Default

Quote:
Originally Posted by gertbfrow View Post
Im guessing by blue you mean metal halide and for red you mean high pressure sodium.

To answer your question no, in the veg cycle it wont cause any harm it may infact beef them up a little bit.

However, if your using a HPS in flower and switch to a MH, that will mess things up a bit. I use a 1000hps and a 400hps Gavita, the 400hps burnt out and I only had a Gavita 400mh for back up. Only 5 days in the 2nd week of bloom caused a huge increase in leaf production. The plants are so leafy they don't even look like the same strain as the ones under undisturbed hps.


I should have been clearer in my question i guess

I got a couple of CM just sprouted under a 125w blue eco light, and they are stretching way out of control. I had to take the fan off em cause they blew over so i was wondering if i could put them under my HPS for 12 hours a day to try and slow down the stretching. I know im not the first person this has happened to, but i guess it doesnt matter all that much tho cause ill just bury em deep when they get repotted.

Quote:
Originally Posted by L33t View Post
The results showed that although there was a decrease in yields when MH was added or MH light was used exclusively, the benefits in resin production and increased quality in the high were worth it. Not all strains seem to benefit the same and in terms of high the pure sativas showed the most improvement with MH-only light , indicas and hybrids showing little or no improvement.

MH-only lighting showed a decrease of 8% in yield compared to HPS only lighting. The plants grown under MH were a bit leafier but the flowers had greater trichome coverage and the high was more complex and psychedelic with certain clones which shows that some sativas do benefit from a mixed or MH only lighting.
Btw as advised by ot1 in may be more practical to just add or go full MH only during the last stages of flowering in order to avoid leafy plants yet benefit for the improvement of the high and possible increase in resin production as well.
That is interesting, got a link? Do you think it applies to blue spec from an eco light?

Last edited by Greens; 02-14-2010 at 09:44 AM.
Reply With Quote
  #6  
Old 02-14-2010, 01:42 PM
L33t's Avatar
Senior Member
 
Join Date: Apr 2007
Posts: 3,544
Default

hey Greens

Quote:
Originally Posted by Greens
That is interesting, got a link? Do you think it applies to blue spec from an eco light?
it took me over an hour to find the links but it is really interesting info and it was worth digging it up..

Here are few paragraphs from the conclusions :

Quote:
Originally Posted by oldtimer1
"A clear 1kw HQI-T MH produces the most potent weed followed closely by a mix of 600w son-t and a clear 400w HQI-T not quite as potent with slightly more yield, followed a long long way back for potency by a 1kw son-t-plus but about 8% higher yield in weight than the pure halide. My personal choice for growing are the mixed lights as its really flexible in what you can do. For breeding I go for pure halide all the way. So basically all our findings go right against current thinking. But we are only interested in quality, what the weed does when smoked and not the biggest weight per watt."


Quote:
Originally Posted by oldtimer1
Unfortunately an awful lot of absolute garbage has been written and continually repeated and republished over the years. Drug cannabis only originates from areas in the world where the overall light spectrum never drops below 5400?k. The mellow warm orange light of autumn and its effect on cannabis is just some stoners dream and total crap. If you were up in the Hindu kush [about as far north as really potent cannabis grows wild] long after the harvest and the snow line has come down and and killed the plants! Even then the light is still in the high energy part of the spectrum ie blues and violet.

Virtually all the the base varieties that make up the named indoor lines in Holland today were originally selected and bred in the states. They were developed using metal arc lighting, nice potent varieties. When David Watson took some of these lines to Holland and opened the first seed bank, the Dutch started growing puff inside as well using these lines as they came available. The farmers son’s who were already used to growing under glass using high bay supplementary lighting with low energy requirement crops like chrysanthemums to tomatoes. Took to it like ducks to water and it was only a short step taking the same systems completely indoors using the same low energy spectrum lights and more to the point breeding under them. I suspect this is the main reason for the steady decline in potency of Dutch genetics over the last 20 years.
Full post with all the lighting test info :
http://www.uk420.com/boards/index.ph...17&#entry18917

----------------

Quote:
Originally Posted by oldtimer1
Cannabis psychoactivity has been declining steadily for the last 25 years if you are talking about Dutch genetics, although to some extent it depends on how you define potency. They have slipped from original skunks quite up stone to more and more boring indica couch lock, can’t be arsed to get a drink from the fridge monged out feeling, thats just down to appallingly bad breeding practises.
Full post (post #60) http://www.uk420.com/boards/index.ph...x&#entry808996

----------------
Quote:
Originally Posted by oldtimer1
"I suggest adding the full spectrum blue envirolite would help balance the spectrum a lot more, the plants would be healthier, the short wave light enables the more complex synthesis, in turn that means more potent buds."
from: http://www.uk420.com/boards/index.ph...8&#entry119218

This should answer your Q on the eco light spectrum.


----------------

Quote:
Originally Posted by oldtimer1
"There is no doubt that the inclusion of the high energy spectrum while flowering helps any strain to produce more complex psychoactivity, how much depending on the genetic potential of the variety/s you are growing."
Full post link (post#14): http://www.uk420.com/boards/index.ph...5&#entry120905


Quote:
Originally Posted by oldtimer1
eski high potency cannabis only developed and occurs naturally in areas of high intensity light containing uv. The higher the uv the more complex the thc becomes. Thc is one of the best sunscreens produced in the natural world.

The assumption is that thc protects the developing seed embryo against damage and mutagenic effects of high intensity wide spectrum uv.
link (post #34) http://www.uk420.com/boards/index.ph...x&#entry156232


there are more posts from ot1 on light spectrum and observations so if you are interested to read more do a search over uk420 forums

l33t
__________________
cheers , Haz3

Last edited by L33t; 02-14-2010 at 01:57 PM.
Reply With Quote
  #7  
Old 02-14-2010, 09:23 PM
Senior Member
 
Join Date: Oct 2009
Location: MNS Forums
Posts: 456
Default

[QUOTE=Greens;41685]I should have been clearer in my question i guess

I got a couple of CM just sprouted under a 125w blue eco light, and they are stretching way out of control. I had to take the fan off em cause they blew over so i was wondering if i could put them under my HPS for 12 hours a day to try and slow down the stretching. I know im not the first person this has happened to, but i guess it doesnt matter all that much tho cause ill just bury em deep when they get repotted.QUOTE]

I totally would use a hps in your situation, it will beef out the stems and if you have the space top them so they can fill out more. Unless wattage and heat are an issue your better off going with the hps from the get go as seedling can handle them well. Another thing you might want to do since theyre tipping is to repot now. Having a bigger base will help and the weight will beef up your stem.

Thats an awesome post L33t, awesome soucring. I've really enjoyed your grows and posts on here & icmag.

What would you have to say about finishing off a crop under a low watt MH? I've read that dimming and lowering your day hours in the last week can increase resin production. I was thinking about putting a few big plants that have been flowering under a 1000w under a 400wMH for their last week for 2 reasons, 1., to see if the reducing light/MH theory works for my strain in increasing resin/potency, and 2., I have a bigger crop under the 400w now that three weeks behind and I'd like to give them an extra week of 1000w juice.

Do you think this would work or would I be wasting my time and significantly lowering my yeild?
Reply With Quote
  #8  
Old 02-15-2010, 11:25 AM
L33t's Avatar
Senior Member
 
Join Date: Apr 2007
Posts: 3,544
Default

hi gertbfrow,

glad you enjoyed the info in the links , ot1 has been doing various comparison tests over the years with lighting , soil brands , nutes etc and has been conducting his experiments carefully so I take his results seriously esp since they seem to mostly agree with others' observations.

Regarding your Q about lowered wattage I cant really say for sure that reducing wattage in the last week will help with increased resin production but since you have another crop behind I believe you would benefit more at least total-yield wise i you used the 1k for the 3week-behind crop now and put the 400w for the last week of the now finishing crop.

Personally I usually like to just raise my lights 10-15cm in the last week or so for various reasons and seems to work well but I don't really lower the wattage by changing to lower watt bulbs.Raising the lights in the last week/s will help with terpen production (as the HIDs produce a lot of heat) and may also help the plants think they are getting closer to their end and start to ripen and stop new flower growth.

Ideally we would test things out with 2 groups of same clone/same grown plants and go from there..as this is the only way to find out what really happens with resin when intensity is lowered.

I like to try to replicate nature and when it comes to lighting if a strain has origins from areas where the lighting is intense all year long (like equatorial sativas) then I don't really think that having an indoor garden with much lower light intensity esp in the last weeks will help with resin production. So I believe it basically depends on strain and not all strains react the same way.



hi Greens,

If you are still in veg and not running a high-plant-number SOG I would advise you to top like gertbfrow said , it will result in bushier plants which is good for indoors.
BTW Don't stop using the fan alltogether, just leave it on but redirect the airflow so the plants are not hit directly.

You can certainly put the seedlings under the hps for the 12 hrs , just go gradually , first day a couple hrs , next day more hrs till you get to 12hrs so they get used to the HPS light . Some plants are said to not like spectrum/intensity changes much , a more smooth transition will help just in case your plants dont like drastic changes too.

If you want to veg bushy/compact plants I would say get a strong MH(Metal Halide) light (400w or more).

HPS is not really good for seedlings /veg plants as it makes em kinda stretchy (which can be good or bad depending on strain).
__________________
cheers , Haz3
Reply With Quote
  #9  
Old 02-16-2010, 07:01 PM
Senior Member
 
Join Date: Oct 2009
Location: MNS Forums
Posts: 456
Default

Thanks L33t for the response, I'm just trying to decide if I want to go with the 400wMH switch up, or just going with a 1000MH for the last week or two. I read that thread and its amazing how much positive influence the MH has in the quality dept.
Reply With Quote
  #10  
Old 03-05-2010, 03:31 PM
Senior Member
 
Join Date: Nov 2009
Posts: 147
Default

well, after having a read and digesting all this fine information i decided to combine HPS and MH In a double cool tube. Its impossible to judge the results with any real accuracy because any number of factors may have had an effect, not least of which would be the increase in over all light. However, there has definately been a significant resin increase, and a general improvement of all the plants appearance. After around a week, my older CM got very, very resinous, to the point that squeezing the buds left the fingertips feeling more wet than sticky.

I dont want to make any bold claims, because for all i know it was going to do that anyway, but i have to say i am very happy with the results. Im all exicted now
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT. The time now is 11:24 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
SEO by vBSEO 3.6.0 PL2
All rights reserved, MR NICE SEEDBANK, NL