easy now yall,

2 questions. firstly im using a 250MH bulb for growth and am going to swap for a 600HPS bulb when flowering.... when is it best to switch over? same time as when swap to 12/12?

secondly, will i see any real extra in yield/quality if i keep the 250Metal halide in there aswell as the 600 during flower?
both in those cheap shitty reflectors that cost cple quid.. gona get cooltube for the 600 but be cple weeks...
the 600's a dual spectrum but 250 isnt obv...

u veg with both aswell?

Put the HPS in when you go 12/12

Don't know if the metal hallide will make any difference because your plants are utalising a different end of the light spectrum..... actually, as I think about this I'm willing to say it has very little to no benafit at all. Buy a 250w HPS and use that, the metal halloide will just be a waste of electricity. If you want, find a bulb with a slightly different spectrum.... something with a bit of purple perhaps?

All the best

Hi Growstar, I was wondering wether to finish a grow on MH or HPS, any suggestions?
they'e sats. at around a month to go

Cheers

metal halide light is like feeding your plants a nice healthy balanced meal, good for them, but wont fatten them up as much as a big fat greasy HPS all day breakfast. MH light for quality, HPS light for bulk. ideally you want a mix of the two

a really good source of info is the sunmaster grow-lamps website, i cant link up to it, but just go to the website and click on the lights and plants tab on the left of the home page. a must for all growers imo!!

Very well phrased!

I do believe the point of grow lamps is to replicate the sun. However, the sun has a FULL spectrum where no machine can replicate this diversity. As the earth tilts on its axis the lightwaves that hit the earth shift from blue to red. As I'm sure the plants will utalise the MH light it deveates from the natural shift in light spectrum the plants experience outdorrs. Again, as I'm sure there will be an effect on the grow the law of diminishing returs kicks in.... how much of the blue spectrum are you ustalising and how much more of the red could you be utalising. If mony, space, time and heat are not an issure do whatever you like but as I said before, perhaps take the time to choose the right HPS bulb instead of the metal hallide bulb. BAng for buck and all that ...

I have done grows with only mh, only hps and various mixes. HPS on its own definately the best in my experience.

Important to remember that hps gives out more lumens per watt than mh. I am of the opinion (Can't prove scientifically)that the extra lumens of hps makes up for any deficiencies on spectrum front.

If at all possible I would always veg under 600w hps rather than a 250w halide.More lumens more yield.
In absence of anything else it can only help if 250 mh is in there for flowering as well as 600. Just move em around so all plants get a mix of light is my take on it.
My tuppence worth
Papa

HPS for sure! The metal Halloide doesn't have the essentials the plant would need

I have to disagree with you... Use the MH in veg and the HPS in flower. If you use 600 watts in veg and are enging with 600 watts you won't be utalising its maximum output untill the last 3 or 4 weeks. Even though the lumen output is increast the plant needs less light even in terms of proportion (ie, a meter squared of plants in veg use less light than a meter squared in flower). Give your plants as much as they will use, anything else is a waste of resources and money!

Regarding the origional issue posted. The aditional 250 MH is not needed in THIS SPECIFIC INSTANCE. Dohickee stated that he is using a 600 watt full spectrum bulb (I'm asuming this is a growlux). SO the plant IS recieveing some of the blue spectrum! It doesn't need another 250 watts of MH, give it HPS instead. I'm not sure of the numbers is as follows: 250 watts added to 600 wattes represents 40% of the output and aproximately the same in lumens (forget for the time being that the 600 watt is full sepctrum) If the plan is using less than 40% of the blues specturm (which I'm quite sure it is) than it is a waste of output. This is the law of diminishing returns: get the MOST out of what you put in, when the retun dicipates in relation to what you put in you are losing out! Seeing as there is a full spectrum bulb being used there is plenty of blue spectrum coming through. Another point to consider is that the penatration of 250 wattis about 2 feet (at the most) where the 600 watt is about 3.5 feet. You will have to adjust the lights to allow for this difference. But again, it would be better to stick a 250 watt HPS bulb into your ballest.

What can I say, I'm an economy grower

the old, red light in flower myth ganja grows and flowers naturally in places where at 12/12 daylight hours, there's virtually no red shift anyway, and even if it did naturally grow in higher latitudes where we get more red light in autumn, the red shift in natural light, is NOTHING in comparison to the light you get from an HPS lamp, the closest lamp that matches natural light is ceramic metal halide, the second closest match is a 4000k standard MH, the furthest deviation from natural light is HPS by FAR. hence why everything looks normal under mh light, and orangey yellow under HPS light. the general rule of thumb if you can is a 40/60 mix of mh/hps. i.e. for a 1000watt grow 400w mh and a 600w hps. don't get me wrong. hps alone can give great results, but plants are much healthier and more resinous grown with additional mh. and before anyone mentions dual spectrum hps, they don't even touch on the colour rendition of MH.

Its all due strain you are growing IMO....some strain will be better/higher in potency some will be the same it will just cut your yield,so best to get informed/tested what Your strain likes most.

law of diminishing returns, means you get less for the extra input you put in, you still get MORE overall than without it, just at a slightly lower efficiency.... SO WHAT!!?

(purely hypothetical) i can get 600grams if i use 600watts, or i can get 750 grams if i use 850watts. i know what i and any other sensible person would choose


all this is irrelevant anyway. what's the size of the grow area and the size of your extraction, as it's these that will determine whether you can get away with both lamps

how will adding an extra 250w cut yield? or i think you're reffering to changing the 600 for mh at the end of the grow?

secondly, will i see any real extra in yield/quality if i keep the 250Metal halide in there aswell as the 600 during flower?
both in those cheap shitty reflectors that cost cple quid.. gona get cooltube for the 600 but be cple weeks...
the 600's a dual spectrum but 250 isnt obv...



to answer the original post YES and YES.... if you have extraction capable of controlling the temperature

Your disagreement agrees with me. If all other conditions are perfet then its obvious to throw in more light, but if other conditions are fixed like grow area and ventalation its not worth while. The other point I was making is that the light wouldn't be utalised in proportion to the output (so even the hypothetical, 750 grams you refer to is an unjustified criticism).

But aside from all this I think Scraglor has set the record straight... I stand corrected. But there is still an economic issue to consider as well as the effect on the environment that we all agree on.

you got me wrong mate

No i dont think adding aditional 250w will cut your yield. do it

I was refering off / comparing use off 600Mh vs 600Hps trough flower and its affect on potency/yield.

Maybe i got lost in the thread s ,i should of read thread better sorry

i wasn't trying to correct you, juts pointing out, you still get more overall, a 250 watt lamp costs efall to run over the duration of a grow,and it will of course add yield, despite diminishing returns.

but if other conditions are fixed like grow area and ventalation its not worth while.

and i in no way agreed with this. if grow space remains the same, (again as example) you will get more bud at the end of a grow with 80watts per square foot, than you will with 50watts per square foot, you might not be hitting a g/watt, but who gives... you'll still end up with a considerable amount of extra weed

e2@: in fact if growspace IS limited, then the only way you can get more weed is by dropping your efficiency, by adding more light, spending on boosters etc, you're efficiency will go down, due to diminishing returns, but your yield will go up. if i have only 2square feet to grow in, i could use a 100watt lamp and hope to get 100grams, or i could stick a 250w in there and get 150, i might have shit efficiency, but i've also got an extra 50grams of weed

thought so, wasn't 100% sure though

evening all, not had a chance to look back at this for few hrs and got quite an interestin read

by the time i got thru this there where far too many quotes for me to add replys to so just a wee line try and awnser evrythin..

thanks v.much for the debate. . . good read.
efficency is not really an issue yet as am just geting running strong then will fine tune.
dont really want to buy a 250hps as cant make grow shop for few weeks.... can a hps just go into the ballast im using for mh? i assume so..
ive got this all in a 1.2msq budbox tent with 4 plants (only 3 for flower) hence efficency not issue all getn monster'd in 60l pots(maybe bigger)
using a 6' rvk for extract, no filter yet
growing seedsman white widow as its very forgiving, and from seed under this MH lamp they've flourished nicely, however a bit slow i think.

i think it was scraglor xplained it close to what im after.. hypothetically, if my conditions where excelent and i pulled 600grams from my 600w hps, if i kept the 250w mh would i pull and xtra 100-200grams of weed?

v.highjust nowso will need to re-read tmoz i think

with a 6" for extract you'll want a 5" intake and it should cope with both the lamps, depending on where you intake from, lights on at night, that kinda thing. with sensible planning, and at this time of year, with an intake fan, (or a massive passive intake) then you should be ok.

850w in that area is even way overkill anyway! in fact it's pretty bang on the money, 850w divided by 16 sq feet is only 53 watts per foot!! so defo do it.

it will make it harder to achieve g/watt as said earlier, if you have less light covering a larger area, your grow will obviously be more efficient, fuck if i had a single 400watt covering 50 square feet, i'd obviously have a lot of shit scraggly weedy plants around the edges, but i bet you a 1000quid i could still pull over 2 grams per watt at the end of it!

being efficient with your power is just being inefficient with your space, which most people don't grasp (obviously up to a point, where the plants simply cannot take in any more light, but this is close to the 90 watts per foot mark!!!)

as for the lamp, depending on what type of ballast you have, you may or may not be able to put an hps lamp on it, it almost always works with a mh halide running from an hps ballast, but more often than not it wont work the other way round. get the details up of your ballast and i'll let you know if it's even worth trying. if it were me though i'd use a mh anyway, as it makes the plants much healthier as has already been said

My experience agrees with that reported by others (including Oldtimer1, who's experiments with MH & HPS are what decided me to try it out), that a grow flowered under a 60/40% mix of HPS and MH is marginally more psychoactive than one done under either of them alone. Over the years I have played with HPS alone, MH alone, and various combinations for flowering. I always come back the the 60/40 if possible. Its not possible for me at the moment, so I tend to flower under HPS for weeks 1 - 5, then swap bulbs for a MH. In my grow, that's optimum lighting for optimum punch.
But the differences are small. I'd ignore them, but every time I flower with a touch of MH, family and friends alike all remark that "this is better than..." whatever crop I last grew under HPS solo.
Dunno about any so-called "science". I just grow dope and like it to smoke right. And for my taste, that means a bit of HPS and a bit of MH

Why not play around with various combo's and see what you prefer?

cheers for all the info buddy, helpin alot
my grow is in a mates spare room just now as im movin soon so i'll check out the ballast tday and post back tonight

e2a is 2g a watt possible? most i've heard reported genuinely was 1.4g a watt (ish)


this sounds v.interesting, if it can make your stuff more trippy then why not..
but yeah i've done just hps grows before then an envirolite grow, so think way forward is mixin it up.. im allways changing strain tho.
think im sticking with this White widow for a while now so be a perfect time to test out

For a real interesting read here on the effects of diiferent lighting on canna click here. And as Arny said, do some research here on OT1 and lighting. From what I can tell, OT1 has dome the most intensive and long term research on lighting here at UK420.

it was more to prove a point really, yes you could in theory get 2g per watt, but it'd be mostly shit not worth smoking. i.e. you could fill a whole room with plants and only have 1 400w light in the middle, all the plants would grow and flower. but all except the ones close to the light would be really loose, crappy airbud, you need high intensity to get dense tight nugs of bud, but you'd still overall get more than 2g/watt. so your grow would technically be efficient, but your use of space would be very inneficient

whereas at the other end of the spectrum (my old CO2 dosed grow as an example) i had 100watts per square foot, 1 x 400w in a 2 x 2ft space, with CO2 i'd get around 14 Oz + (normally with 400watts and the correct space, say around 60-70watts per square foot, with CO2 you can expect around 21 Oz from a 400watt light or 1.5g/watt even going up to 2g/watt!) so my g/watt efficiency was terrible, not even hitting a g/watt with CO2, but the efficiency of my space was outstanding! getting close to 3.5-4oz per square foot!!

basically high intensity/watts per square foot = efficient use of space, poor use of energy

low intensity/low watts per foot = efficient use of energy, poor use of space

Or use a light rail to achieve a middle ground.

don't really get light rails though? surely you still need the same 37+ watts per foot, trying to cover a larger area will just mean plants spend less time under intense light, equals smaller buds, just mean you get a more even spread, from say your 1000watter, you don't want it sitting in the middle the whole time miles away from the plants at the edge

I can grow more buds and use less leccy and generate less heat with a rail. The lamp can also be closer to the plants which offsets the limited exposure (as the lamp moves back and forth) somewhat. You also get more even coverage that way.

Most likely it's better to have multiple lights to create even coverage, but if saving money on leccy bills is a priority, I think the rail is the way to go.

A 2 meter linear rail perfectly covers a one by two meter tray. I'm very satisfied with my buds from my 600W lamps and rail.

cool, yeah that makes sense! what kind of extra stationary wattage do think the light rail compares to? if that makes sense

No idea dude. I just started using rails as I have a lot of space, but limited leccy. I'm actually a bit of a noob of a grower, just very handy and open minded about learning.

furry nuff

gotcha
kina forgot to check my ballast, as i am wantin to know about that..
will post what it is tmoz

got one of the lightrail 3.5 things but used it for a grow, before i knew shit to be honest, had a 600w hps on it but ventilation was non-existent, had about 20/25 plants under it...
ended up pretty much what scrag describes
load of, well shit really
about 4oz off the lot..... was unbelieveably balls
real fuckhead that year ahaha would probably be able to make it work bit smarter now i know i bit more but beginnin to like the tents idea

Ventilation is key, especially with that many plants. I was doing 21 plants max per rail (I have 4 rails, 3 for flowering, one for vegging). I was getting, at worst, a 1/2 oz per plant with peaks of up to 1.5 oz per plants. After ventilation I found my biggest gains after I got my compost properly sorted by the good folks here @ UK420.

But I think SCROG is the future now. Fewer plants, less work, more yield.

yeah i like this, however this nxt grow will be a SOG with 20plants 5 in every 2week with no veg

sog is easier imo, just the plant numbers that's a worry. doing a scrog now, only for plants over a metre squared, just a pita pruning and training, but once all that's done, no worries at all, don't really give a rats about being caught with four plants, was a bit more worried when i had a 30 plant sog

I strongly recommend you read my third diary. First post explains why I went from SOG to SCROG. I was harvesting 6 plants every week.