# MH 24/7?  safe?



## Lougie (Jun 27, 2013)

Can you run MH 400 watt conversion bulbs 24/7?

I've heard 18/6 is better for the bulb???  Does it not really matter?


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## 4u2sm0ke (Jun 28, 2013)

I run 24/7..and have for a couple yrs now...


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## Dr. Green Fang (Jun 28, 2013)

I ran my 400W MH bulb 24/7 for about 6 weeks straight... but then bought a T5 fixture for an all around much better light! I can drop the light RIGHT to the tops of the plants without burning them, and they just love it. 

:aok:


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## The Hemp Goddess (Jun 28, 2013)

I have never run a MH conversion bulb, but I ran MH for many years before I discovered T5s.  I always ran 24/7 when vegging.  However if you can spring for a T5, I have found them to be superior to MH in most ways.


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## YYZ Skinhead (Jun 29, 2013)

I have run 430w Agro 24/7 since 1998.  Prior to that I used fluoros all day.  AFAIK 18/6 merely wears out the bulb more quickly.


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## LEFTHAND (Jul 7, 2013)

I've never ran an mh before now. 
Which I'm running a conversion 600. 
Along with a hps 600. 

But I can tell u I've ran hps alot 24/7. 
When I first started thus like u I was worried. 
But I contacted lumetek. N asked a few questions on there ballast going 24/7 for 1-2 months. Then onto 12/12. 

From what I can remember they said 1-2 times a week shut er down for 20-30 minutes. Allowing bulb n ballast to cool compleatly then fire n go again. 
LH


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## DrFever (Jul 7, 2013)

To be honest running lights other then florescent s for seedlings and or for clones on 24 is wasting your money.. i have believed for a long time that all plants need some darkness ( Cool down period ) i found better overall growth rates with 18/6  then 24 hrs of straight lighting   and of course  power consumption is allot less running 18/6


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## LEFTHAND (Jul 7, 2013)

Lol. Agreed. Lol. 
On the fact it's kinda silly to run hid for a couple seedlings or clones. Unless the can be tossed in a room with such lighting. 

But it's my understanding that mj does not require a "sleeping" dark period. 
During the vegetive state. 
In my personal findings I have found the opposite. If the temp is controlled to proper temps. N watered along with nutes properly they thrive bushing n not stretching as I have found alot if strains to do in 18/6. 
The cost of t5's to be shut down 6 hrs a day saves cents 
Along with in 4 days u loose a day of full sun. 
Just my thoughts n opinion 
LH.


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## DrFever (Jul 7, 2013)

You must of miss understood me i was trying to say  running flourescents on 24 hrs is fine running hids is a waste of money on 24 hrs i have done both  and to me 18 /6 is by far more superior   i prob run one of the most  dialed in rooms  where if a person farted it would detect it lol  with temps C02 and everything monitored to a tee here some girls  35 days from a 3" clone  on 18 /6   would love to see a 36 day plant on 24 hrs look like this


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## LEFTHAND (Jul 7, 2013)

I'm not here to have a peeing contest. 

I'm sure you have a nice room but I have to disagree. 6 hrs of extra hid isn't gonna break a wallet 
I will post a pic of a lady 14 days veg n 14 in 12/12. I think she's wonderful aint nothing special. considering the fact it was vegged under CFls. Lol. 

But this is another one of those "opinions" like flushing. Or sweating out your herb when drying. 
LH


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## DrFever (Jul 7, 2013)

6 hrs  in 5 weeks  works out to   210 hrs  x that by charge and see now of course means nothing if your growing low wattage but 3 - 5 10 thousand watts ?? do the math


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## DrFever (Jul 7, 2013)

Bottom line tho to each there own i always looked at growing like mother nature  
 and that is night times involved  lots of people just think plants grow but when you get into the science of  plants   there so much more to growing and understanding  for instance  my night time temps ) when lights are off  are in the  65 mark  which has benefits and are lost when lights are on 24 hr  settings cause your plants never  get that cool down period 
Hell after my plants get 18 hrs of light   there begging for a rest 
  from the physiological effects on plant growth and flower development, having a lower night temperature setting has other beneficial effects on plant processes. Firstly root pressure is greater at night under cooler conditions - this increases the pressure in the xylem vessels, so that calcium and other plant growth compounds which are carried in the xylem stream are forced out to the leaf tips and into developing buds, flowers and fruits. This turgor pressure is often essential in the prevention of tip burn as it ensures calcium is carried to the very edges of the leaves. Often, this root or xylem pressure can be seen in the form of 'guttation' which are visible droplets of water which can be seen at the tips of leaves on plants in the early morning. It is this root or xylem pressure which also acts to 'pump up' the plant during the cooler night temperatures particularly after a day when transpiration rates and warm temperatures have resulted in some wilting and loss of turgour


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## LEFTHAND (Jul 7, 2013)

"This is a direct quote from Ed Rosenthal whom most of you know:
I personally think he's a dink but that's me. 


Marijuana plants photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrum's) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air.

Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with the sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant's metabolic processes, respiration and growth, continue.

The plant can photosynthesize continuously so it produces the most energy and growth when the light is on, continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically to it.

Plants under an 18-6 light-dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants, faster, which leads to higher yields."

"The following information is straight from Greg Green's "The Cannabis Grow Bible"

Cannabis is a light demanding plant. Professional growers keep the light on their plants using the 24/0 photoperiod for this reason. Plants that grow under 24/0 flourish and do not need a quantity of darkness in order to rest and perform photosynthesis properly. Plants that are grown in optimal conditions under 24/0 light regime grow vigorusly and the benefits of a 24/0 photoperiod can be seen actively in the results. More nodes are formed, more branches are created, leaf numbers increase, the plant is growing at its finest.

Some growers opt to use 18/6 as their photoperiod. This is 18 hours of light, six hours of darkness light regime. Under these conditions the plant will grow quite naturally but not as vigorously as the 24/0 photoperiod.

The 18/6 photoperiod expels 3/4 the amount of light that a 24/0 photoperiod does. Although this does not mean that a plant produces 1/4 less leaves,branches and nodes under the 18/6 photoperiod, it certainly does show the correlation between light and cannabis growth. As we have said already, cannabis is a light demanding plant. There are no problems associated with 24/0 and although some have attributed cannabis sexual dysfunction (the hermaphrodite conditon) to 18/6 photoperiod these problems are actually the result of heat stress.

A 24/0 photoperiod requires that your grow room temperature be kept well monitored. The 18/6 option is cheaper to run. You use a quarter less electricity and this will have an impact on your electricity bill. Also the 18/6 photoperiod will generally extend the bulb's lifespan. During the 6 hours of darkness the grow room is allowed to cool down for this period but a well maintained good grow room setup should not require a cooling down period.

24/0 and 18/6 both share the same problem though. Once you start the photoperiod you should keep that way especially when the plants near maturity (the preflowering stage). An irregular photoperiod can cause more males than females to develop. It can also cause sexual dysfunction to appear. Whether you choose 24/0 or 18/6 as your vegetative photoperiod try to keep that photoperiod unitl your plants are mature enough to express their sex."
LH


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## DrFever (Jul 7, 2013)

Quote :  Some growers opt to use 18/6 as their photoperiod. This is 18 hours of light, six hours of darkness light regime. Under these conditions the plant will grow quite naturally but not as vigorously as the 24/0 photoperiod.  

Could you post your 24/0 plants as you mentioned   i understand  it was a CFL grow    here is  some under   96 watts  of sunblaster  flourescent    on 18/6      9 - 10  week VEG    
when growing under 24 hr lighting i saw no big significant growth  all i got was a smaller plant that grew little more bushy here another plant  week old from rooted clone  still on 24 hr and prior to  transplant then onto 18 / 6  and   LST


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## Sin inc (Jul 25, 2013)

i always ran 24/0 in veg  .if you find that your plant are not doing well or grow diffrent on a 24/0 then its more then likey .something to do with your growing tec. just my lil tought . my best friend she grows on a 18/6. she helps me grow out my plants. we always start at the same time. she use's the same light and soil and tec. the only diffrent is 18/6 vs 24/0 . my crop almost always get to 12/12 about 2 weeks ahead of hers.


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## 7greeneyes (Jul 25, 2013)

I run my mhconv lamp 24/7 when I have it on. I got a t5 fixture I havent put up but will soon once I start full timing again (veg and bloom) but up till then my 400 watt mhconv lamp has worked flawlessly. Just don't turn it off then on again real quick or it'll take forever to kick back on.


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## N.E.wguy (Jul 28, 2013)

i'm more concerned i'm high 24/7


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## 7greeneyes (Jul 29, 2013)

:rofl:
:stoned:

u 2?

lol...


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