Vertical Bulb Placement ?

I have a question for you Vertical growers , as I am going to reset up my 3' x 3' room for a vertical duel bare bulb grow. FYI: Heat issues are of no concern ,I have the ability of a 40 degree temp dif.


I am going to use 2/ 400w hps bulbs ,I will hang the overhead bulb in the standard position of bulb facing in the vertical downwards position,Now here is my question , when positioning the lower 400w bulb is it more beneficial to face the bulb in the vertical downwards position (same direction as the overhead bulb ) or positioning the bulb facing in the upwards position (opposite position ) .

Aim it up so the base shadows the floor imo.

Make sure the bulbs you have can be run vertical. Some won't work that way.

It doesn't matter one single bit really. The light coming from the tip of the bulb is next to nothing while the light coming from the base is absolutely nothing. More important to keep them in the correct position relative to the plants. I see time and time again that the bulb is actually above the highest point of the canopy.

I don't know why people do that but it certainly doesn't make sense in terms of light energy and physics

legallyflying said:

It doesn't matter one single bit really. The light coming from the tip of the bulb is next to nothing while the light coming from the base is absolutely nothing. More important to keep them in the correct position relative to the plants. I see time and time again that the bulb is actually above the highest point of the canopy.

I don't know why people do that but it certainly doesn't make sense in terms of light energy and physics

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i raise the light to get it to stretch a bit, then ill lower it when i want them to bush out. first time going vertical though so im taking all the advice i can. just thought id answer why i put my bulb higher then canopy,.

Why would you ever want a plant to stretch? Just curious.

If you really want it to stretch then get it cold in there with lights off. A higher temp differential will result in much more stretching BTW.

I find stretching highly beneficial in vert set-ups. Our canopies are filled vertically, so more vertical growth = more sqft canopy area, though this is more true of donuts than multi-level grows.

But even in multi level grows, I find that hybrids perform better than stout indicas, because of the added stretch.

legallyflying said:

Why would you ever want a plant to stretch? Just curious.

If you really want it to stretch then get it cold in there with lights off. A higher temp differential will result in much more stretching BTW.

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Stretch and train, maximise your foot print. once stretched you can bend the branches at the back of you plants around and into your cage. If done right, your cage should be pure bud by chop chop time.

I'm going to have to agree to disagree. I scrog another room so know very well about training and creating a wall of weed. But very or not, the tighter your node spacing, the more plant biomass you can fit in a finite space, and the higher the yields. I'm not trying to start a pissing match or anything, I'm just saying I prefer a plant that fills a whole screen AND has a whole mother later of buds begins it because it's so dense.

legallyflying said:

I'm going to have to agree to disagree. I scrog another room so know very well about training and creating a wall of weed. But very or not, the tighter your node spacing, the more plant biomass you can fit in a finite space, and the higher the yields. I'm not trying to start a pissing match or anything, I'm just saying I prefer a plant that fills a whole screen AND has a whole mother later of buds begins it because it's so dense.

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Thank you. I was waiting for someone to reply regarding node spacing and allowing a plant to grow WHILE MAINTAINING that tight spacing to produce better. Stretching does nothing except cover more area with less dense buds.

Typically, are lower branches that are farther away from the light better in quality, maturity, and yield? No. What do lower branches of the plant do in typical grows? Stretch.

slamsomethc said:

Typically, are lower branches that are farther away from the light better in quality, maturity, and yield? No. What do lower branches of the plant do in typical grows? Stretch.

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With vertical growing, your lower branches receive almost as much light as the branches in the middle and on top - there is no canopy to shade them.

People who have never grown vertically usually find it hard, at first, to understand the sometimes contradictory growing information they see and hear before they try it themselves. That's OK - everything's a learning process. And it's fine to agree to disagree. But you really shouldn't dismiss something until you have tried it yourself - especially if many others have tried it successfully themselves.



Others have already explained why stretch can be beneficial in a vertical system - the easy answer being that it increases the light canopy or growing area.

With the entire plant side-lit, those long branches WILL fill in - because the lower nodes are not being shaded as the stems stretch and grow.

Growing vertically, you will see this for yourself. However, the simplest example would be to have two identical strains - one grown short and bushy, the other grown tall and lanky.

First problem: you cannot fit as many bushy plants around your vertical light as lanky plants - this limits your plant numbers (higher plant numbers invariably produce more yield for the same wattage, all things being equal and light distribution being optimum).

Second problem: the bushy plants cannot take advantage of stacked lighting (two or three bubs hanging vertically in a row, one on top of the other).

So now you have a smaller number of bushy plants that are exposed to less light - because they are not tall enough to take advantage of an extra bulb hanging on top of another (1x600w HPS versus 2x600w HPS, for example) - and so obvioously your yields are going to suffer.

But the third problem is this: the bushy plants do not have good light penetration from the side - they are too thick. It is the same principle as top-lighting - except you need to turn everything on its side to understand how it all works. The thick plants will have nice buds on one side, but scraggly, under-developed buds on the other side.

Of course, you can try turning your bushy plants regularly, but then each bud site is only getting half the direct light (watt hours) for each 50:50 turn. You end up with many bud sites with average development.

Vertical growing is not the same as horizontal growing The same methodologies cannot always be applied.

I think we are over simplifying things. There are far too many variations on vertical growing to say this or that is right.

Stadium, cages, trees, double stacked lights..

I will tell you this though and this is absolutely the truth, the tighter your spacing the more biomass and leaf area there is for the production of carbohydrates that will ultimately result in flower formation. A bigger plant will ALWAYS produce more ALWAYS. A plants yield is quite simply the result of the balance between production and utilization of carbohydrates. The more it can produce the more it will yield.

You do have to factor in light saturation, co2, temps... Basically all the parameters that govern chemical relations but at the core bigger or tighter is more..that was my point

legallyflying said:

I think we are over simplifying things. There are far too many variations on vertical growing to say this or that is right.

Stadium, cages, trees, double stacked lights..

I will tell you this though and this is absolutely the truth, the tighter your spacing the more biomass and leaf area there is for the production of carbohydrates that will ultimately result in flower formation. A bigger plant will ALWAYS produce more ALWAYS. A plants yield is quite simply the result of the balance between production and utilization of carbohydrates. The more it can produce the more it will yield.

You do have to factor in light saturation, co2, temps... Basically all the parameters that govern chemical relations but at the core bigger or tighter is more..that was my point

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What you are saying is true in relation to horizontal. Vert has very different rules.

With horizontal, every inch your plant grows, you have to push your light an inch further up. Your main cola will grow (as it does for obvious reasons) at a quicker rate than the rest of the plant and the distance from light to main body is ever increasing and the only part of the plant getting optimum exposure to the light is the top of the main cola. Not the case with vert.

With a horizontal plant there are essentially 3 tiers of growth. The bottom third which is a total waste of energy and is stipped back by most growers, then the middle third which is fair to middling and the top third being ya main colas. The difference in light quality between tiers being massive, from more than it can handle down to almost nothing. Not the case in vert. The way I grow I essentially have 2 tiers of bud. The front layer where every inch of facing bud is equally served by my bulbs and no more than 12inch away from source. The second tier is about 16 inches from the bulb recieving significantly less light but again every inch receiving light. Not the case in horizontal.

Stretch in vert allows more light to the second layer eliminating poxy popcorn and every bud worthy of your time and effort.

"A plants yield is quite simply the result of the balance between production and utilization of carbohydrates. The more it can produce the more it will yield."

This is mostly true but should include the fact that rate of production and utilization of carbohydrates is directly proportionate to the quality of light provided. Vert canopy receives an equal spread and hugely better quality / intensity of light than a conventional horizontal grow.

Mashed and rambling...

legallyflying said:

I think we are over simplifying things. There are far too many variations on vertical growing to say this or that is right.

Stadium, cages, trees, double stacked lights..

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The principles are the same no matter the growing style: vertical lighting is more optimum than horizontal lighting because there is no reflector (reflected light is weaker than direct light), and you are making use of almost 360 degrees of direct light (vertical) instead of about 120 degrees of direct light and 240 degrees of reflected light (horizontal). There is also less canopy heat (no hoods to trap heat from the bulb), and you can get your plants very close to the bulb/s.

legallyflying said:

I will tell you this though and this is absolutely the truth, the tighter your spacing the more biomass and leaf area there is for the production of carbohydrates that will ultimately result in flower formation.

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In my opinion, this is rarely true. My indicas have tighter nodes than my haze plants, and my haze plants absolutely kill my indicas for yield - 2-3 times as much yield each and every grow.

Tighter nodes can actually limit bud production, because as each node flowers, it grows and shields light from the node above it. If you have intermediately spaced nodes to begin with, each bud site tends to fill the space in-between and does not get shaded. Dense growth has its limits (and is also prone to mould).

My Stinky Cat Piss Haze is a classic example of this: it stretches like you wouldn't believe, then fills in all the nodes with long, sticky buds that make maximum use of the vertical lighting while my more compact plants don't. Haze varieties consistently yield better than other strains in my vertical set-up.

legallyflying said:

A bigger plant will ALWAYS produce more ALWAYS. A plants yield is quite simply the result of the balance between production and utilization of carbohydrates. The more it can produce the more it will yield.

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Indeed. A 5'-6' tall haze will outyield a 3'-4' indica in my set-up every time. But what you have to remember is "bigger" can also mean "longer" as well as "thicker" (never mind the width, gov, feel the length).

legallyflying said:

You do have to factor in light saturation, co2, temps... Basically all the parameters that govern chemical relations but at the core bigger or tighter is more..that was my point

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This is where we obviously agree to disagree. All things being equal, tight nodes are certainly no guarantee of high yields in vertical growing. It is only really true of horizontal growing.

Why? Because tight nodes in horizontal growing go hand-in-hand with light intensity - the denser the light, the tighter the nodes for a particular strain. And this is because both the light and nodes are growing UP - stacking on top of each other. Vertical buds grow OUT and up - not straight up.

If a horizontal system doesn't have enough light, the plant will stretch, the nodes will be further spaced, and the lower branches will get less and less light as you raise the lamp to keep up with plant growth.

Vertical lights stay pretty much where they are in comparison (they're raised a little during bloom to keep up with plant growth, but only a little). If you don't have enough light, the buds tend to be airy. But the node spacing isn't affected as much, because the plant isn't stretching UP towards the light, it is stretch OUT towards the light.

See the difference? You need to turn everything you have ever learned on its side

I don't really have any explanation for it, but I do have my experience - and in my grow, with my growing conditions, hybrids grow much better and yield better than stout indicas that don't stretch. I find that in order for indicas to produce well in vert grows, they need quite a bit more veg time, and just really screws up my schedule. If I were growing indicas regularly, I'd have a hood and a clone factory / SOG grow going on. I prefer sativa dominate hybrids which suits my growing style well.


When I put a plant in flowering at 18" and gives me a healthy flowering stretch and finishes up at 36" I have a nice full canopy that is full of buds. Not colas and larf, a wall full of dense nug.

When I put a plant in flowering that is 18" and it finishes up at 24", I'm missing out on a ton of useable light.

It's the equivalent of having a 3x3 horizontal scog, and only filling 2/3 of your screen.

There are some MASSIVE yielding sativa and sat dom's out there, they all stretch healthy, this gives the buds room to grow. Colas as big as your leg!

^ Yep, what you've said right there. In 10 years of vertical growing, my highest-yielding strains have ALL been haze hybrids or sativa-dom hybrids. They often take a little longer to finish than my indicas (but not all), but the yields are still comparably higher when flowering time is taken into account.

vertical and horizontal bulbs in my room.. cant wait to see results

AlterEgo860 said:

vertical and horizontal bulbs in my room.. cant wait to see results

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Now thats just fukin greedy lol. keep us posted.

.. figured wat the fuck. I forgot.. im running 3 hps.. and 2 mh.. the mh are vert in between the 3 hps hoods ... I wanted the extra light and spectrum I heard great things about adding mh . so fuck it .

Prawn Connery said:

^ Yep, what you've said right there. In 10 years of vertical growing, my highest-yielding strains have ALL been haze hybrids or sativa-dom hybrids. They often take a little longer to finish than my indicas (but not all), but the yields are still comparably higher when flowering time is taken into account.

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While I appreciate and generally agree with what you guys are sayin....
... Sometimes however,, I really like a indica. When I do I don't let vertical hold me back,, I'll just run the veg time 2X that of my sats or until they hit 30 to 32" in heigth. Time consiming yes. But I like the variety that indicas offer too.