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MH and its Imact on Trich Development

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Farang    48

 

I read this a bit ago and adopted it for my crop because I’m about as lazy as they come.

 The poster assured everyone that using the MH bulb through the first two weeks of flowering increases trichome production.  His theory was that Trichomes are generated to protect the plant/calyxes from the blue end of the spectrum.

 Maybe.  I dunno; I’m no biologist.  But a couple of things occur to me.  First is that for the first few weeks after they switch to flowering, there are no Trichomes to begin with.  Calyxes are small and immature, so what is the MH doing for the plants?

 If his theory were correct, wouldn’t it be better to use the MH bulb at the end of the flowering cycle rather than the beginning?  Doing so would, if he’s correct, bolster the trich development and ripening and, because MH bulbs produce fewer lumens than HPS bulbs, would lower the light amounts to the plant while maintaining the 12/12 formula.

 As a side question, does anyone think a Reduced Light Schedule is a good thing?  If it is then moving the MH exposure to the end of flowering might be a good thing after all.

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Grow_Wizzard    558

What does the outdoor season do? In the spring the sun starts moving closer and the days grow longer, thus the plants grow in veg mode. After the solestace, (longest day of the year) the sun moves away and the light fades intensity and duration. Seems your observation would be correct, Since you have 2 400 W fixtures, have you considered changing bulbs or if you have the room run both fixtures and only kick the MH light on for about 4 hours in the middle of the 12 on cycle? Just a thought on my end. would be an interesting test to see yields and flower structure. May cost a bit more but if it improves the yield it may be worth it. Again I only grow outdoors. so I'm not an indoor expert.

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LabRat    905

I recently found an old, 2012, Skunk magazine that I'd never read and there is an article by The Rev in there about using a particular type of MH light bulb for the whole grow.  They run off a 400w magnetic ballast and are called the EYE Clean-Arc MT400D/HOR.  Check out the spectrum diagram for that bulb.  Full light right across the board and not a bunch of different spikes.  I wish they made them in 1000w as I have that ballast and only one 400w MH magnetic.  Got 3 - 400w HPS ballasts too with lights for them.  The Eye Hortilux conversion bulb I bought for flowering with my 1000MH was $170 and I bet that EYE would be less than half that.  EYE Lighting and EYE Hortilux are different companies now I believe.

 

Ceramic Metal Halide bulbs have a similar spectrum and some, if not all,  run off of HPS magnetic ballasts or digital.

Leaving your veg light on during the stretch helps to limit the stretch but won't make any difference to trichome production at that stage if you switch to HPS for the balance of flowering.  May help to switch back to MH for the last couple weeks tho but I'm not sure.

:peace:

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Farang    48

so that's why I don't get much of a stretch???  the MH light?

something else to think about.

thanks, guys!

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Shaughnny    283

Basically if your plants are too far from the light source they will stretch. During the first few weeks of flower your plants will naturally stretch and reach. The idea of the trichomes purpose being that they are generated to protect the plant/calyxes from the blue end of the spectrum....never heard that before my friend. From the reading that I have done over the last 15+ years is that the trichomes provide a sticky protection to help protect against disease and undesirable insects. Also it has been suggested that some of the reason for all that oooey gooey goodness is to help the female cannabis plant capture the males pollen.

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Farang    48

thanks, Shaughnny.

the concept of trichs helping to attract pollen is what I first heard, but since then, I have read in multiple places that it is more protective than attractive.  I'm certainly no biologist, so I'll defer to those who are trained and knowledgeable on the subject.

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weedmen    423

the real reason for resin production is the plants way of keeping bugs from attacking the plant ..the bugs get caught in the resin and they die ..the plant will kill the bug by resticting its ability to exscape ..trichs are the resin glands and produce the resin for this reason..the resin is also to catch pollen and hold it for pollenation..it forms on leafs as well as the flowers for these reason .. ..the psyco-active part of the plant ..the thc and cbd's are part of the plants defence as well.

 

.i read this yrs ago and it seems to make the most sense to me ..

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weedmen    423

i read somewere that using a mh will cause the end product to be more potent and using a hps will cause the end product to yeild higher ..or it maybe the other way around ..but anyways , i can say since changing my light from hps to mh , my buds seem alot tighter and harder ..altho i guess it could be the genetics . but its the same with a cpl of the diffrent strains i grow .not just one . so i am doughting its from genetics or strain oriented..

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Unregistered    169
On 2017-01-23 at 8:44 AM, weedmen said:

the real reason for resin production is the plants way of keeping bugs from attacking the plant ..the bugs get caught in the resin and they die ..the plant will kill the bug by resticting its ability to exscape ..trichs are the resin glands and produce the resin for this reason..the resin is also to catch pollen and hold it for pollenation..it forms on leafs as well as the flowers for these reason .. ..the psyco-active part of the plant ..the thc and cbd's are part of the plants defence as well.

 

.i read this yrs ago and it seems to make the most sense to me ..

Except for the pollen catching bit, ya, seems most reasonable.... terpenes will battle mold/bacteria/viruses, organisms with a nervous system would be affected by the cannabinoids.

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Farang    48

Weedmen, you switched from HPS to MH at the end and your buds were tighter and harder?

this lends credence to that guy's theory.  as this is mostly a throw away crop this year, I may try it for the last week or three.

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weedmen    423

 just threw the whole buding period ..i used to grow from start to finish under hps and my buds would be a little whispy it seemed .but now i am using the mh during buding and the buds seem much tighter and harder ..some of the diffrance maybe strain related as well ..i was growing a lot of diffrant strains then.

anyonme else seen this happen..

 

i no some veg under mh and bud under hps ..maybe that should be switched around ..bud under mh and veg with hps..might make for  better nugs..

i can remeber when most folks only grew under mh ..it was all we new back then to use for lights that would actully give ya real buds ..lol..

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Farang    48

I've grown under all HPS but not under all MH.

it would be nice to get some input from other members on this site.

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LabRat    905

Not all lights have a well balanced spectrum so generally you do better by using MH until the stretch is over then switching to HPS.  Ceramic metal halides have good PAR values right across the spectrum and a lot of people are using them these days for the whole grow.  Those MH bulbs I listed a ways back in this thread would do the trick as well.

:peace:

 

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Farang    48

thanks for your input, Labby.

this contradicts what someone said above in this thread that MH stops stretch (and leads to looser, lighter buds).  and I always heard/read that HPS all the way through was superior.

I'm confused, as usual.

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weedmen    423

once you have a good idea of what works best for your situation . just dial it in and do your own thing ..i think to much is being put in to thinking about some of this stuff and we just need to find whats working and stick to it ..sharing info is one thing but knocking our brains around trying to see what others are doing and trying to copy it . its just not worth all those brain cells ..i dont have many left to worry about it  ..lol

what works best for some , may not be what does for others ..i get the whole idea of wanting to grow the best we can .but it can be confusing at times ..

 

i think stretch is going to happen no matter what lights we use ..the whole change in light patterns or dark and light periods is a way of stressing the plant and its reacting by stretching ..if we could run our lights the way the sun moves across the sky and at the same length of time and same spectrums..we wouldnt see stretching ..i cant ever recall having any stretching going on outdoors when starting from seed to harvest outdoors ..altho if we did follow the same patterns as the sun . our indoor grows would take a whole season or summer to finish ..lol altho i can recall a good rain making the plants jump up or grow larger faster ..but no real stretching..

a little stretching is ok for me ..i try and make it work for me ..i no if i put plants in one end of my tent at 12 to 14 inches tall and the farthest from the light. i no that by the time i harvest the ones infront of them that are right under the lights , the 12 inch plants will have stretched to about 18 to 24 inches and thats were i like to keep my canopy around 18 to 24 inches ..i have only grown the three strains out in my tent . it maybe diffrent for diffrent strains ..but for now its working out great ..

 

Edited by weedmen

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Farang    48

thanks for saying all that.  I've never been able to get my plants to adhere to what so many others are saying/doing.  I could beat myself up for not being able to duplicate what they claim or just go with what I have and make the best of it.

the concept of indoor lighting is supposed to duplicate or even improve on natural sunlight.  that's never going to happen, but we do the best we can considering the myriad of shortcomings involved.  there are movable tracks which better simulate the sun's movement, but the expense......I'm not at all sure it is worth the price.  but opinions are like assholes: everybody's got one.

there was no such thing as stretching back in the 70's growing outside.  I never get stretch growing inside, either, but that may be because I keep my lights down tight to the top of the canopy.  in doing so, I don't think it would matter if I were using MH or HPS lamps.  if I wanted stretch, the obvious way to achieve that would be to raise my lamps; however, doing so basically deprives the plant of efficient lighting and probably results in weak stems.

I keep my shorter plants more centered to the lamp in the hopes that they catch up with the leggy ones.  I do see the advantages of having an even canopy and distributing the light in the most efficient manner possible.

still, if you and others are saying that replacing the HPS with MH at the end of the flowering cycle produces tighter buds with more Trichomes, I would love the affirmation prior to my adopting that method.

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Shadey    241

Interesting discussion, I was under the impression that stretch after switching to 12/12 was something that occurred because of the photo period change not the light frequencies. No one is mentioning what happens with an LED full spectrum light. From the discussion here, I am assuming there will be, none or very little stretch, other than natural growth rate, which I can estimate from the time it has taken to reach the height they are at, before switching, to the 12/12.

 

My concern over this, is at what height I should flip at, to keep them around 48-54 " at finish. Genetics are unknown unfortunately, and I know there are many things that will affect eventual height but what would be a safe height to let them grow too before switching to 12/12 roughly. I was thinking 18 inches but after reading this thread, I am thinking 2 ft. In general is there a rough guide one can follow?

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frmrgrl    369
13 hours ago, Shadey said:

In general is there a rough guide one can follow?

Indicas and mostly indica hybrids will typically double in size during 12/12.  Sativas tend to grow almost the whole cycle, sometimes they'll triple in size.  Mostly sativa hybrids are somewhere in between, leaning closer to the double mark rather than the triple mark.

 

Under my full spectrum LEDs, I still see the same amount of stretch (rapid, compact growth, not lengthening internode intervals)....and this is under 50+ DLI.

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Shadey    241
56 minutes ago, frmrgrl said:

sativa hybrids are somewhere in between, leaning closer to the double mark rather than the triple mark.

Well I think that's what I have, so I will stay safe and switch at about 21 inches 50/50 compromise. You like making me work for my answers lol. Had to look it it up 50+DLI, for the lurkers :) ,    refers to the number of photons, received (ordinary by plants) during one day in the PAR region. As your light is probably a lot better than mine, that should make me even safer, I hope.

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I always liked to flower under mixed spectrums..

 

usually=

2x 1000w HPS per 1 1000w enhanced spectrum MH. 

 

gotta love that ratio.

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frmrgrl    369

Shadey - made you look :grin:.

 

ics - good to see you posting again:boob:

 

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Doobie Brother    1,027

Hey Innercity.  Times certainly have changed!  

 

I never quite understood why one would use MH during flowering, when trich development clearly favours a redder spectrum... seems to be a waste of electricitty, as why not simply add an extra HPS ?

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