A Multi-Shelf Garden Setup -or-
What the Heck is a Trellis?

by pH

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The Question Was Asked:

>Everyone seems to prefer MH or HPS lighting. While fewer lights means less 
>labor, this system wastes verticle room capacity.  Especially for a Sea of 
>Green system.
>
>I have yet to find anyone that has used a verticle mullti-shelf method 
>with Flourencents.  Ultimately the question becomes;  Does the space 
>gained by verticle shelving and Floro's sacrafice yield to where standard 
>MH or HPS are prefered?
>
>Thanks for posting replys

Tricky question. Because fluoros can be used with the multi-shelf method and HID's cannot (unless you have very, very high ceilings), the new dimension of yield per sqaure foot of "FLOOR SPACE" seems to be an added benefit of using fluoros.

I have been using fluoros with the multi-shelf method for a few years. In a floor space of 2'2"x4'7" I have two 2x4 foot shelves, each with 320 watts of fluors used exclusively for flowering. My ceiling height is normal, at 8 feet. The limitations I found are mainly with headroom, but differing elevations with ebb/flow hydro make it VERY tricky to manage fill/drain times. For example, with one pump supplying both shelves the top shelf takes longer to fill, but will siphon faster than the lower shelf simply because of the elevation difference. WIth some experimenting one can find a happy medium.

Using hydro with a reservoir the lower shelf MUST be at an elevation higher than the reservoir for siphoning (or any draining) to work. BTW I use the same lines that feed the solution into the growing beds to siphon the solution out of the beds when the pump shuts off (I also have overflows for each bed).

Basically, each shelf provides 34 inches of vertical space. Given that the beds are 8 inches deep, and the fluoro fixtures are 5 inches thick that gives me 21 inches of total vertical space for plant growth on each shelf. I top my plants at 10 inches, because 10 inches above the bed is a horizontal trellis of 2" poultry netting. It is used to train the plants to grow horizontally once the shoots reach it. Nothing grows above the netting UNTIL buds start to form and upward growth slows down, THEN they are allowed to grow vertically through the netting. The netting is great, and provides a perfectly flat profile to match that of the flouros, ALL buds are the same distance from the light source. Try to visualize a 2x4 foot flat area filled with nothing but buds. WIth only one or two plants per shelf it is not in the true sense of the term "Sea of Green", but it is a sea of green none the less.

Now we're getting close to where the rubber meets the road, so to speak. At this point I have buds growing into a space 11 inches high. Given that fluoros should be 1 or 2 inches from the buds this gives a total of let's say 9 vertical inches for just bud growth. It is at this point where a double edged sword appears, and where I think HID's are an advantage because of their light penetration qualities. 1-Some buds do indeed want to be longer than 9 inches and nothing can be done short of cutting the bud, or training the bud to grow horizontally. The former works OK, and the latter produces buds with one side resinous and the other side (the side facing down) non-resinous. 2-WIth 9 inch buds, the base of the buds are 9" away the fluoros, this doesn't make for good resin development at the base of the buds.

Right now I'm planning to get a HID. Of course it cannot be used with the multi-shelf method, but I will continue to use a trellis because of the positive impact it has on overall vertical productivity. I believe the HID will eliminate the distance-to-light-source problem found with fluoros and very long buds. I have the floor space, so why not add it and give it a shot.

Getting back to your original question. 

>Does the space gained by verticle shelving and Floro's sacrafice yield to 
>where standard MH or HPS are prefered?

Yield per square foot of "floor space" would address the vertical aspect of your question. Below is my contribution to the Yield-O-Rama, it's equal to that of HPS. 

  GRAMS
  DRY WT    HARVEST        WATTS/LIGHTING     MEDIUM/STOCK  variety
  ------    -------        --------------     ------------  -------
  17.5      MANICURED      40 FLUOR           HYDRO,CLONES  I

Doubling that for a two shelf vertical setup is 35 grams per square foot of floor space. That seems to equal most HID yields in the Y-O-R.

TRELLIS

Actually I top the plants when they reach the netting, they're about 12 inches tall at that point. The 10" mentioned in the post refers to headroom between the netting and the lights, for maturing buds. Don't bend tops over anymore since only the shoots make for better, more even, horizontal growth.

I try not to weave the shoots (over/under) the netting, but rather tuck them down under and redirect them to the next 2" opening once they've outgrown the one they're in.

Once they hit the netting ALL grwoth remains at 2" from the fluoro tubes, they hang just above the netting and are only raised when the flowering tops start to "slowly" grow upward, at this point I have also stopped training the shoots under the netting.

You're correct in saying the "lower" internodes get more light, but that is not the purpose of the netting. I want to make that point here. In fact lower internodes are still lower internodes no matter what system is used, "they wont ever" be as good as nodes closer to the light. I still cut off lower shoots that never make it to the netting, because that's where all the action is happening as far as I'm concerned. The purpose of the netting is to get all growing tips that will be used for buds to grow at the same height relative to the lights, and it accomplishes this task superbly. My harvest consists of many, many, tertiary and quadernary shoots that have grown into buds between 3 to 6 inches long, and primary and secondary shoots that can be as long as 10 inches. I would venture to say that if I used HID lights instead of flouros the buds would be even longer and fuller, but I would lose the headroom the low profile (about 3 inches) of the fluoros provide and therefore could not have one shelf on top of the other.

In a trellised horizontal configuration the canopy is where the rubber meets the road, it receives ALL the light with NO gaps allowed. In a vertical configuration the spaces between plants is where you lose most of your production (either in yield or quality), not the shoots that can be considered undergrowth. You'll always have undergrowth, but you don't always have to have gaps if you manage horizontal growth to fill them. I found a trellis to be the best way to do this.

If you've never seen it, you have to try to visualize a 2x4 foot section of 2" wire netting with at least one, but usually two (and sometimes three) good buds growing from EACH hole. Of course, practice makes perfect:-) Using this method I get 10-12 oz of primo bud, with 40WATTS/sq ft, from each harvest using two shelves in 2x4 ft of floor space. BTW I have normal 8ft ceilings.

More on the trellis

With the trellis the canopy fills very fast, about 2-4 weeks. Try to visualize these two examples. One topped clone, in a corner of a 2x4 ft area with a trellis 10 inches above. By the time primary shoots have grown horizontally 4 ft to reach the other side, I am starting to tuck 6" tertiary and 2" quadernary shoots under the center of the netting. One layer of shoots under the netting is a full canopy, any more than that is overgrowth and either interferes with existing bud sites or replaces them. Another easier way may be to imagine a 4 ft plant sandwiched flat between two 2x4 ft panes of glass, then put under a 2x4 ft bank of fluoros. The profile of each shoot may be seen clearly through the glass with one plant, but put a second plant in that sandwich and you can see what I mean by overgrowth.

The art is in timing induction to the number of plants, so overgrowth is avoided yet the canopy is full.

More on the trellis

> I'm really interested in the poultry netting that you use at 10".  This
> poultry netting, is it chicken wire?  Could you describe it to me?
Yes, it is run-of-the-mill chicken wire.

> Are the holes in the netting 2" big, square, round?
They are 2 inches. That's the way chicken wire is avalable, at least in my area. I can buy either 1" or 2" chicken wire (or poultry netting as it is sometimes called), 1" is too small. The shape is actally more like an octagon. I can buy it in 2 foot wide rolls, I think 4 foot is available, but not certain.

> Should I double stalk as usual?
With the trellis, yes. You can just bend over the top of the plant, but I found shoots grow faster if it is topped.

> You wrote that "I try not to weave the shoots (over/under) the netting,
> but rather tuck them down under and redirect them to the next 2" opening
> once they've outgrown the one they're in."  I take it you do this cause
> you have limited height available.  If I don't have those limitations
> should I just let them grow up through the wires unattended?
No, not during veg growth. That's where you're actually controlling the horizontal growth, and the upward growth is very fast. As the plants are flowering AND UPWARD GROWTH SLOWS TO A CRAWL is the time to stop training the shoots under the netting. At that point shoot tips growing through the holes are slow growing buds, and the time you spend training shoots will no longer be needed.

> On the other hand, I can also take the plants out of the closet and put
> them outside.  In my part of the world daylight is never more than 12.5
> hours a day during the long days.  After getting 18 hours a day of MH
> light they would probably bud outdoors all by themselves.  What do you
> think?
It would be murder to untangle the plants from the netting once they have grown through. That's why I emphasized that I don't weave the plants over/under.

But if you set it up so that the trellis can simply be lifted straight up, AND no shoots have been allowed to grow through the holes too far, you could move them outdoors. If you've moved them outdoors to bud previously with success that is.

More on the trellis

> Do you know of any reasons to/not to leave the trellis in place all the 
> way through flowering until harvest time?
>
> Seems to me that I remember reading in the original thread discussing 
> trellises that the wire is removed when the lights go on 12/12, but I 
> don't remember why.
At one time someone asked about removing the trellis in order to move plants outdoors to bud. I believe this is where you're confused.

Normally the trellis is not removed.

When buds start to form heavily on shoot tips and upward growth slows down to a crawl (about 2-4 weeks after induction), you can stop training the shoot tips under the netting and allow the buds to grow through until harvest. Until this time arrives you're simply training shoot tips under the netting so each hole in the netting will have buds when they do start to form. Try to anticipate when the trellised canopy will be full, so you can start induction early enough to avoid overgrowth. Don't wait for the canopy to be full before inducing flowering. This takes a little practice and a familiarity with the variety you grow.

The trellis is what keeps the sea of buds horizontal and at an equal distance from the lights. I never remove the trellis, no need to.

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