Volume of root zone per sq/ft

Thought this would be an interesting survey. How much solution do you use per square foot of canopy space that's available for the roots to occupy? Some evidence indicates no benefit doubling a .65 gallon per sq/ft root zone.

Too much math

I could help you out if I would understand all the measurements in feet, gallons, oz's

The basis of the topic regards optimal root zone volume. The light cycles people use indoors are meant to force flowering rather than replicate nature, so restricting the root zone might be a useful way of getting the morphology to fall in line with the light cycle. As mentioned, there is anecdotal evidence that providing too large a root zone, in DWC at least, causes more vertical growth and less yield.

Basically, is getting root bound a good thing, and if so, when should it happen? Does this apply to other media like soil and soilless?

Not sure if this applies, but I have 6 footers root bound in 2 gal. soiless media pots and there is plenty of mass abive ground.

CoB_nUt said:

Not sure if this applies, but I have 6 footers root bound in 2 gal. soiless media pots and there is plenty of mass abive ground.

Click to expand...

How many pots and how much canopy space?

For instance, the soilless grows I've done I used 5 gallon pots (4 gallons of media), 8 plants in a 20 sq/ft area. That's 32 gallons of media for 20 sq/ft so 1.6 gallons of media per square foot. That's probably on the high side and I might play around with using less in the future.

I have no experience and did not test it in any way.
What I can say is that commercial growers for lettuce, herbs and other plants, who use hydrosystems, give their roots plenty of space.
And I guess they want large yields.

Perhaps this is a simplification but over the years I read so many things that would provide stronger plants, bigger yields, shorter veg-time, whatever.
It is - as you said before - often anecdotical.

It makes sense with plants where the product is vegetative matter. In our case we want the vegetative growth to stop at some point so the nutrients are diverted to flower production.

In my case the difference was very pronounced. Plants with the extra root zone space were more than a foot taller, yield was less, product more fluffy. Everything else was exactly the same, space, light intensity, airflow, strain, etc. The only difference was volume of the root zone and nutrient solution.

Being anecdotal there are parameters to be considered. Nitrogen ppm was normalized to 100 per gallon, but having 2x the nutrient solution the larger root zone had twice as much nitrogen. Perhaps more to the point with 2x solution N levels would remain more stable and closer to 100 ppm toward the end of the week... so it's not just root zone size involved. If it's assumed high N availability was responsible for the extra vegetative growth one solution would be to keep the root zone large and cut out more N going into flower.

Rahz said:

How many pots and how much canopy space?

For instance, the soilless grows I've done I used 5 gallon pots (4 gallons of media), 8 plants in a 20 sq/ft area. That's 32 gallons of media for 20 sq/ft so 1.6 gallons of media per square foot. That's probably on the high side and I might play around with using less in the future.

Click to expand...

2x 2 gal pot. Both plants in a 4.5x4.5x 7 ish tent. 1 gal in the rear has a 3.5' x 2'.5 canopy, and the gal in the front of the tent a canopy of aprox. 3'x 2.5'.
They were slightly over vegged ( 4 weeks). I supercropped them @ 3 feet well into the 3rd week of flower. They shook that shit off and exploded! My cob rails are literally on the ceiling of the tent, minus 4" for the passive sinks to be passive and some airflow up there.
They really screwed my perpetual run up taking uo so much real estate. Oh and the media is the same I use for my ppks, Perlite & Allsport calcinined clay.

I guess it depends on how you grow... Here's a daily maintained Waterfarm thread, right here on RIU, no remote reservoir, under a 100 days, from seed, 11oz... This WF could have been connected to a 10 gal reservoir and the yield would have been little different...
If you want better yields in a faster time frame, change the way you grow, hydro or soilless, and quit trying to mimic nature... Make the plant respond to your will.. Controlled growth with a scrog screen, and day length light manipulation will yield much more than long legged plants... In much less time..



https://www.rollitup.org/t/pineapple-express-g13-labs-seed-to-harvest.344359/
It's all in the first 12 pages.

CoB_nUt said:

2x 2 gal pot. Both plants in a 4.5x4.5x 7 ish tent. 1 gal in the rear has a 3.5' x 2'.5 canopy, and the gal in the front of the tent a canopy of aprox. 3'x 2.5'.
They were slightly over vegged ( 4 weeks). I supercropped them @ 3 feet well into the 3rd week of flower. They shook that shit off and exploded! My cob rails are literally on the ceiling of the tent, minus 4" for the passive sinks to be passive and some airflow up there.
They really screwed my perpetual run up taking uo so much real estate. Oh and the media is the same I use for my ppks, Perlite & Allsport calcinined clay.

Click to expand...

Wow, if I'm reading right that's 4 gallons of soil in a 20 sq/ft area which comes to .2 gallons per square foot. I will try smaller pots and see how it affects things.

mytwhyt said:

I guess it depends on how you grow... Here's a daily maintained Waterfarm thread, right here on RIU, no remote reservoir, under a 100 days, from seed, 11oz... This WF could have been connected to a 10 gal reservoir and the yield would have been little different...
If you want better yields in a faster time frame, change the way you grow, hydro or soilless, and quit trying to mimic nature... Make the plant respond to your will.. Controlled growth with a scrog screen, and day length light manipulation will yield much more than long legged plants... In much less time..

https://www.rollitup.org/t/pineapple-express-g13-labs-seed-to-harvest.344359/
It's all in the first 12 pages.

Click to expand...

Yea, that's kinda what I'm getting at. It's kind of an obscure topic, so we're probably not going to find root zone side by side tests. I didn't intentionally test it myself it just worked out that way. I'm doing pretty well with some methods. The bubble buckets produced 1.8 gpw, 24oz using a custom built 400w LED. Roots come out in the shape of the bucket. In the 20 gallon tub the result was similar... not a 20 gallon root ball but at least 10-12 gallons of root mass, so at least twice the root mass. That was a 1.35 gpw yield, same lights, strain, etc. as mentioned.

I suspect, but have no proof and might be wrong, that continued root growth into 12/12 promotes excess vegetative growth in the plant and in the product. I'm not suggesting it delays flowering, but that maybe there's a correlation between root expansion and vegetative growth with artificial light cycles that isn't apparent in nature.

I think to proof this, you need to try time after time under controlled circumstances.
But perhaps you can find some literature about the subject.