Okay, new set of questions in preparation for a SOG attempt.

So from my first grow I realized that I need to make a couple of changes. With the lighting I have I shouldn't be growing four footers. The undersides of the plant were just pathetic, though turning herm had soemthign to do with this the 250 HPS just didn't penetrate far enough. The side CFLs did a little but not much.

Okay, so my closet is 2 X 2...

I want to attempt a sea of green in this small space. I ordered ten white widow seeds. In this small space, allowing for females how many should I start? Accounting for the probability of a couple of males.

I want to keep focus on short plants and cut down the veg time so more light can focus on less plant. How tall should they be before I flower? A friend said I should veg them for two weeks. Accounting for plants that are not that tall how many should/could I flower?

Should I bother with chicken wire or anything? The point is to put each cola and brance through these to even out growth right? How high up and when should I use the wire? 6 inches, 1 foot? Just after I start flowering and sex?

I'm going to keep my 250 HPS since the space is so small and go from two CFLs to four. I'm going to put one in each corner I think. Sound good? Keep in mind the size of the space I think a 400w would cause too much of a heat issue.

Thanks for your help

This article is intended to provide information for new growers using the "ScrOG" or "Screen of Green" method in mini or micro cabinets under small HPS lights, in the range of 70 to 250 watts. I won't discuss the application at 400, 600 and 1000 watts, as that's outside the scope of my experience. See the "links" post below for further materials regarding 400 watt and other scrogs.


Small HPS lights

Small HPS lights are perfect for growing cannabis in restricted space conditions, as they produce the most light from a given amount of electricity of any suitable lamp for cultivation, and produce a spectrum that is favorable for flower growth. The spectrum is not the best for vegetative growth, but that isn't really important to scrog growing, as the vegetative period is so short. Lights as small as 35 watts are available by stripping components from security lights commonly available at discount hardware stores. 250 watt lights can produce as much per foot in scrog conditions as 1000 watt lights in room growing. A single 70 watt lightcan produce enough for an average pot smoker in a space as small as 1 sq. ft. MH lights are available in small sizes, but they produce less light and more heat than their HPS counterparts, and heat is an important consideration in cabinet-style growing. Regarding fluorescents, the light to heat ratio is even worse, and I am not aware of any situation in micro and mini growing where I would favor them over small HPS lights.

Note that these lights are quite weak compared to 400, 600 or 1000 watt lights used in production growing. Intensity means that the light can be father away from the plant and still be bright enough at the bud surface to produce. Intensity is necessary for tight bud formation.

To get the most out of a small HPS light, you must keep the bud sites within the productive range of the bulb, a lopsided sphere extending out from the lamp source. For a 250 watt light, that circle of light extends out about 20" from the lamp. For a 70 watt light, the maximum distance is apparently around 8" (per chthonic, who has experience with the lights). A group of tall, skinny plants under such a light would only be properly lit at the very tops of the plants, leaving the bottom parts shaded out and in a low intensity light field, producing small, lightweight buds at best.

Ideally you would like all the buds within that magic circle of light intensity, and you would like that sphere of light completely filled with buds. How can that be accomplished?



The scrog method

The essential detail of the scrog method is a screen, usually poultry netting, typically suspended between the planting medium and the lamp. The plants grow up to the screen and then are "trained" under the screen, resulting in a flat table of plant growth, a field rather than a forest. Because all the buds are growing at the same height, it is possible to get all the growth within the effective circle of light from the lamp, maximizing production from the space. It's really that simple.

Well, nothing new under the sun, the method has been used for years. In modern terms, the method was first popularized on the internet by the work of pH on the usenet group Alt Drugs Pot Cultivation, or "ADPC" for short. You can access ADPC from several web-based sources, and pH still posts there regularly. But the method as initially used by pH was designed to tweak production from a large area under fluorescent lights, like the "multi-shelf" method explained in his article on N.P. Kaye's Lycaeum site. N.P. Kaye is in fact credited with the term "screen of green", which pH shortened to "ScrOG".

I am aware of a least one grower who used scrog and HID lights before that time, based on a mention in Robert Clarke's book "Marijuana Botany", which was also a source for pH. But most work involving scrog and HID lights is quite recent. It is noted by pH that the first "yield-o-rama" post for HID scrog was in July of 1997. I became aware of the method from a medical grower in the final days of the Hemp B.C. boards, Savapalet, a posting buddy of Aeric 77.

Before discussing the method in detail, let's explore the other alternative for small HPS lights, the plantlet sea of green method.


Sea of green

The plantlet sea of green method was developed to maximize the speed of cannabis growing in limited height situations. In a typical sea of green setup of this type, clones are planted at densities as high as 9 per sq. ft. Within a short time after being established, the lights are switched to a 12 hour dark period. What happens to the planted clone?

The clone could just sit there, stretch a bit under the light regime, and flower, producing a tiny little bud with a couple of seeds. But that rarely, if ever, happens. Instead the clone takes off in a rush of growth, forming a woody main stem and branches. If the plant is suitable for sea of green growing, it will stop short of the lights and flower. Most indica dominated plants stop short enough to be grown using this method. That process is at the heart of the sea of green method, as it results in the smallest possible plant flowering in the quickest possible time.

Why does the clone act in this manner? The actual process is subject to debate. Your author suspects that the clone reads the light switch as fall, and has a mechanism that recognizes that it's too small to produce seed. So the clone goes into a furious growth mode that stops when the plant reaches a minimum height set within its genetic software, and then flowers. Others argue that the clone's response is just a variation on the normal stretching process that happens when flowering is forced in any size plant. For purposes of the discussion here, it doesn't really matter why the response occurs, just that you can rely on it.

The problem with the sea of green method under small HPS lamps is that it produces a number of small spikes under the lamp, a forest rather than a field. The plants crowd each other out and shade the lower portions, which in any event are too far from the light source. As we discussed above, tall and skinny is not productive under a small light. I grew initially using this method, based on books and magazines that I read before designing my 250 watt system, and it worked well for many years, yielding just over 1 oz. per ft. Not bad, but it can be so much better.

Note that in the mid-90's, the term "sea of green" started being applied to much larger plants and grows, even multiple 1000 watt installations over room-sized grow tables, with 3 foot plants spaced at one per foot. It seems the original meaning of the term, the SSSC plantlet method, has been almost forgotten.

Basic flat, fast scrog

The screen method used by pH relied on a long vegetative period for the plants to cover a large area of screen held close to a series of fluorescent tubes. The method I will describe here uses the same sort of growth process that occurs in a sea of green plant, and is very fast. The screen should be set about 8-12" above the planting medium, if possible. There are two purposes for that gap. First, you have to get your hands underneath the screen in order to handle the plant shoots and to remove excess growth shaded out under the screen. Second, there needs to be sufficient space for the plant to branch. Branching is essential to scrog. I prefer a space of about 10" for a 250 watt light, but some growers prefer shorter gaps for smaller lights, as little as 4-6".

Note that the screen does not have to be absolutely flat, and there are good arguments for dishing the screen to match the curvature of the light field. I don't radically dish my screen, but I do tie down the middle of the screen to prevent the screen from being pushed up, which would be counter-productive.

The clones are set under the screen at a density of about 1 plant per sq. ft. Experience in using the method with various types of plants may result in more or fewer plants, but 1 per ft. is a good starting point. Note that plant density is much lower than for plantlet-method sea of green. That means fewer clones to manage and fewer plants to be holding in a bust, a factor in sentencing guidelines.

Why clones, by the way? By the time you find out which plants are male and female from seed, it would be impossible to extract the males from the foliage wound into the screen and fill in the gaps with female shoots, without a real mess on your hands. Seed plants also waste several inches of height before a mature stem section is reached from which branching can begin, whereas clones branch right from the medium. Height control is typically a limiting factor in cabinet growing. With female seeds it may be possible to grow a predictable scrog by raising the screen height, making up for the wasted stem length. Seed plants may react differently to forcing as well. I have no experience growing from seed.

The clones are established and kicked into vegetative growth. Assuming an 8-12" gap, just about the time where the growing tips penetrate a few inches above the screen, say at two weeks, the lights are switched to a 12 hour dark period. Ideally a response similar to the sea of green method kicks in as explained above. Instead of stopping and flowering, the plants take off, filling the screen with growth. At a density of 1 plant per ft., it usually works out that the plants stop and "crown off" just as the screen is filled. It's really magic to see it happen. Note that this timing method is not universal. Different plants may require more vegetative growth, or perhaps even less. My advice is to start by forcing early, because overgrowth creates an unproductive canopy, more salad than buds.

The timing is so critical. You must be around during this period to guide the growth under the screen, and to make sure all gaps in the screen are filled, one bud site per screen hole with standard poultry netting (2 x 3 inch holes). Excess leaf growth must be removed above the screen, which usually means all the fan leaves are removed. Never mind arguments about whether fan leaves should or should not be left on plants, this is a different animal, and the rule here is, all bud sites must see the lamp in order to develop. At least in a small scrog grow, fan leaves would overwhelm the neighboring buds. Get a good sharp, clean set of pruning scissors and just leave them with the grow. You'll need them every couple of days during this period.

Training really isn't difficult. With a limber plant I usually let the shoots grow vertically above the screen and then pull them under by the stem, re-orienting the stem horizontally under the screen to line up bud sites with screen holes. You don't have to tie anything down, as the upward pressure of the stem will nail the foliage to the screen, but some growers like to tie off stems to the screen during the early phases of screen filling. Here's what one grower, Ultimate, has to say on the subject:

"I swear by twist ties and have a huge stock. They can be found just about anywhere. Purchase ties which are most flexible (wire with the smallest diameter) and coated with plastic not paper, as the paper will eventually mold.

"So why twist tie? Two reasons when training for in any screen application.

1. Pre-training. (Exact placement of main stems, growth shoots and branches)

2. Bud-training. (Bending, stem crushing/crimping, and repositioning)

"When initially induced to 12/12, the main tip/tips that hit the netting are immediately trained 90 degrees perpendicular to the netting. This allows for the light to concentrate the most productive part of the plant, forcing the most efficient production the plant can dish out. Branches under the netting are allowed some time to reach the light, but less than half will see light because you're concentrating on efficiency. The most efficient growth will occur where the main stem bends on a 90 degree and beyond, which receives the most light.

"I like to leave the ties long enough for the plant hold the shape desired. Main stem usually around the second week (give or take) , and branches will always vary. Branches coming off the main stem parallel to the netting are spread as far from the main stem as possible making for a even canopy, more bud sites per square, and controlling overall height.

"To a certain extent the buds freeze at a certain point and height/stem length slows. The canopy height is close to being established, but some plants are more vigorous than others and continue stretch beyond the rest of the crop. When bud training the longer colas are controlled by bending and tying down to the screen with twist ties. In extreme cases crushing/crimping is necessary. Moldy buds can be avoided by repositioning buds growing against each other. By using twist ties each bud can be positioned where air flows between each cola allowing efficient light dispersal within the canopy and better air flow.

"Without ties? Yield was lower. A few larger colas had to be tied down shielding smaller buds from direct light, not to mention forcing the light to be raised higher, lowering production (This can be resolved by switching to a more intense bulb) . Some branches grew buds with LONG stems between the screen and base of the cola to compete with the large colas. Hybrid vigor in some cases, or plants which tend to "stretch" more than others eventually straighten out the 90 degree angle exposing less area of the most efficient portion on the plant and eventually stretches to a point where more stem was exposed to direct light, above the screen than desired. A view from the bottom (planter to the screen) showed that efficiency could be improved."

Some plants have brittle stems, and are difficult to train. It is possible to bend a stem by crushing it lightly at the bend. So long as the structures in the plant that carry fluids aren't damaged too much, the shoot will heal and be just fine (thanks to Uncle Ben for that trick). It may also be possible to top brittle plants under the screen, so that the future growth will be in several, more slender shoots. I have no experience in training a scrog grow by topping.

The second pruning step occurs during and after the screen is filled. All growth under the screen must now be clipped off. Shaded growth quickly shrivels and dies, leaving ideal growth mediums for mold. Excess leaves and shoots should be clipped close to the stem, to avoid leaving stumps as mold sites. Robert Clarke recommends pruning away from the stem, but a lot of the standard advice has to be discarded when dealing with the special conditions of a scrog grow. The space under the screen is dark and humid, and you want as little plant material under there as possible. You will haul out buckets of leaves and excess shoots from a scrog grow, but the plants can take it. Clip away.

Subsequent pruning is really limited once the plant sets buds and stops growing. Some plants develop large leaves from the buds themselves, and if the leaves shade out neighboring bud sites, they must be removed. But that's about it. Most of the flowering time in a scrog grow the maintenance level is near zero.

If everything goes well, the extra time required for the plants to reach the screen before the flowering period is lengthened by only about two weeks. No additional time is required to fill the screen, because that time is the same used by the sea of green method to add height. The plants end up just as long, but the growth is directed horizontally. Typically a flat scrog grow ends up resembling a tropical forest canopy, with all the buds in a thick carpet extending 8-10" above the screen. The area underneath the screen contains the tree trunks that support the canopy, like piping connecting the root mat to the canopy.

Thanks man, read this already.

I should clarify again that I will not be using feminized seeds. So I cannot started immediately with SOG. I will have to do it after sexing. So I was trying to get advice from that perspective.

mogie said:

Basic flat, fast scrog

The screen method used by pH relied on..........


.....all the buds in a thick carpet extending 8-10" above the screen. The area underneath the screen contains the tree trunks that support the canopy, like piping connecting the root mat to the canopy.

Click to expand...

Thanks for that Mogie. I've printed out a hardcopy for my room. You have answered many of the questions I had about scrog which I'm planning for a (very near) future grow.

I suggest grow them all, pick ur best plant, clone it and then start ur screen. May take a little longer, but will definately b worth it..

Awesome advice! I was going to SOG but after that I think I now must SCROG. After my current grow(LST, CFL) this is happening!!! +rep

I need to try one of these