Yield per Square Foot? Indoor Grow

EvilTwin said:

Dislexus,
Save the bleach. In open air, pollen only lives a couple weeks.

And leave it to a Californian to bring Karma into the mix... lol
ET

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roshizzzz said:

Another Other Question:

SThat is, a SOG becomes a SCROG when the plants are allowed to get larger than normal SOG-size?

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EvilTwin said:

But...scrog is a veg intensive method that also ties up bloom room time waiting for the screen to fill. Also labor intensive. Not knocking your grow at all VG...most impressive, but this demonstrates the weakness of yield calculations. A sog won't yield like a scrog but it's faster with as little as zero veg time.
ET

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roshizzzz said:

The great info keeps coming. Thanks!

Question:
VG suggested, "6 plants would be fine for 3x3. use big pots"
1. Does this imply that I could grow 6-in-SCROG in a smaller than 3x3 space (and pack more light onto those puppies)?
2. Why big pots?
3. What size is a big pot?
(first grow will be coco, with Canna supplies)

Thanks again. This thread, with all this SOG/SCROG talk, makes me happy as a FROG in PRAGUE.

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Indoor cannabis production is a highly specialized and intensive form of agriculture. Unlike outdoor field or row crop agriculture, which bases productivity on acres, productivity in greenhouses is calculated on a per square foot basis. But unlike greenhouses, which make use of natural sunlight, the overwhelming majority of indoor cannabis gardens are lit entirely by artificial lighting. This puts indoor cannabis gardens in a class of their own.

Light, Space and Indoor Productivity
Outdoor and greenhouse growers base their productivity on yield per unit of area without much concern over the lighting the area receives. The thinking being that the intensity offered from natural sunlight is equal from grower to grower, and that open fields and sunny locations are sought out and selected by those growers to ensure that. The only changes in lighting they need to contend with are those doled out by Mother Nature, something they have no control over. Indoor cannabis gardens are not so fortunate. Indoor light intensity is not equal from grower to grower, and because indoor production depends so strongly on light intensity, the degree to which the average square foot of indoor growing space is productive will vary considerably depending on the type and intensity of artificial lighting chosen by each grower.

For indoor cannabis growers to enjoy the same benefits as conventional outdoor or greenhouse growers, whereby they can discuss and project yields on equal grounds based on past performance, they must account for not only space in their productivity language and calculations but artificial lighting as well. The YOR accounts for these variables by using square feet of canopy space and the average lumens available to that space in its productivity histories and projections. The inseparable interplay between space and available light is crucial to indoor growers, both will ultimately determine the production.

In the same way outdoor and greenhouse growers carefully select a location for their operation, indoor growers carefully select a canopy space within their location (closet, basement, spare bedroom, etc) on which they'll focus their light. The lamp too must be carefully chosen if a target production from that space is to be met.

Targeting Production - Finding and Synchronizing Production with Consumption
One goal of personal-use indoor growers is to divorce themselves from the black market. To be completely self-sustaining a grower needs to produce enough in one harvest to last him to the next. The alternatives - doing without or revisiting the black market - are not acceptable to most. To avoid that a grower must size his indoor garden to at least meet his own personal production needs. Most growers can estimate their needs by finding their weekly cannabis consumption and multiplying it by the number of weeks it takes to grow one full crop. This synchronizes the supply (production) with the demand (consumption).

Vegetative & Turnaround Times
The duration of a full crop depends largely on the maturity (flowering) time of the cannabis strain being grown, and to a lesser extent on the preparatory (vegetative) time preceding it. And though there are growing techniques for shortening or eliminating vegetative time, adding about three weeks of vegetative time to the strain's maturity time is usually a good estimate for the number of weeks it takes to grow one full crop (also known as crop cycle time or turnaround time). Generally speaking, crop turnaround time is about 12 weeks, thus a grower can produce about four crops per year, and each crop would ideally produce what the grower consumes during that 12 weeks.

Safety Margin
Once consumption for the crop turnaround time is known, a crop production target can be established. Experienced growers see production rise and fall from crop to crop even though their garden is in a controlled indoor environment, as the hills and valleys in the graphic at the top of this page indicate. To make up for dips in production, a surplus of about 15% is added to the target as a rainy day safety margin. Some growers like to grow twice as much as they consume, or more, as a safety margin and as a way of planning an extended vacation between crops. Consider your own preferences, then adjust your production target accordingly.

Now that the production target in grams or ounces is known, a decision is made as to how much space and light are needed to meet that target. Space, light, and yield are so integrally tied to one another that you can't change one without affecting the others (see the Lighting Resources for more on space and light). In a perfect world you'd have more light and more space than you could ever want. In the real world, however, indoor real estate is at a premium, and security and cost concerns can nag at a grower to keep space and energy consumption down. This is where priorities are discovered.

One Priority - A Rock or a Hard Place
Is there more space available than could ever possibly be used, or is there limited space that might be too small to meet the production target? If space is limited, one can opt to give the space priority by using more light per square foot of canopy space. Space priority uses more light with less space, but produces the best yield for the available space. If space is unlimited, one can opt to give the light priority by using less light per square foot of canopy space. Light priority uses more space with less light, but produces the best yield for the available lamp.

Most growers want to get all the yield possible from both their lamp and their space. But as you'll see in the Production Table shown on the next page, the interplay occurring between space, lumens, and yield forces a grower to choose which is more important to him.

The Haunting
Because the construction of many grow spaces usually involves hammer meeting nail, the semi-permanent nature of the space can become a nightmare if a grower overestimated its production potential. Tearing down and rebuilding a grow space because it doesn't live up to expectations is something every grower wants to avoid, but most have probably done. Likewise, purchasing new lighting because old lighting proved inadequate is an extra expense that can be avoided with good planning.

Poor planning is usually the result of not having a realistic production target, or guessing at the space and light combination needed to meet it. Armed with a realistic self-sustaining yield target, the predictive resources shown below can help a new indoor grower take the guesswork out of planning, and thus avoid the dreaded re-work and second expenses that come back to haunt so many growers. However, if you don't know your target production, two of the yield calculators contain a self-sufficiency planner to assist you in that regard.

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About the Projected Yields
Yields were calculated using coefficients from Moon Doggie's Analyses for Lumens, 100% HPS Lumens, Hydroponic Media, and for a grower with average gardening experience (5 on a scale from 1 to 10) using a 63-day strain. Thus the yields shown on this page reflect those of the average hydro grower who uses HPS light exclusively.

Given the variable nature of weighing cannabis yields, of normal crop-to-crop production fluctuations, and differences due to acquired productivity skills, your actual yield will vary from those shown. However, if care is taken to avoid extremes, and if you planned for that rainy day surplus, with some normal growing experience you should have no trouble attaining these yields and will most likely exceed them after one or two crops. As mentioned above, these yields were computed for a grower with average gardening experience, not the Albert Einsteins or Michael Jordans or gurus of the growing world.

Using the Table
The table can be used several ways depending on what you know and what you want to find. Here's a few suggestions.

For space priority - Scan horizontally across the table.
For light priority - Scan vertically up and down the table.

If you know your space limitations and target production, but don't know what lighting to use. Find your canopy space in the left column then read across the line until you find a colored cell within the shaded area that meets your target production. The color coding suggests which lamp will supply the lumens for that yield.

If you have your HPS lamp and know your target production, but don't know what space to use. Find the color code for your lamp in the HPS Lamp Color Key, then in the shaded area look for your target production in cells having that color, there may be several. Consider the tradeoffs you'll be making between light and space, then choose the one that best fits your priorities.

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