ImaginaryFriend's INTERPRETATION of Delta9nxs' PASSIVE PLANT KILLERS

Welcome to this most delinquent thread.

In it, I hope to summarize and share the work done by Delta9nxs, and other notable contributors, over the last year while simultaneously documenting my current PPK grow. D9 has worked through various versions of his Passive Plant Killer system and the thread is approaching 60 pages long as I type this. Additionally, I will include some of my understanding of it, and how I've tried to bring it to life in my own world.

None of the technical components in D9's work is necessarily new. I became interested in his thread based on his thoughtful, considered and deliberate approach in compiling information from many sources, and generating what may be...

THE MOST BORING WAY TO GROW IT THE WORLD.

Here is a picture of my two girls, twenty six days of veg, just before their first night of flower:

THREAD INDEX

THREAD INDEX

Hey... as of right now, this 'Thread Index' will keep opening up new tabs in your browser. I haven't found a work around yet...

Delta9nxs' Build and Grow Links
Overview of Delta9nxs' PPK Build
Pulse Feed Technicals Updated September 22 and AGAIN on Oct 9th, 2010 and AGAIN on the 11th.
The How and Why of Media Wicks including Perched Water Tables and Air Gaps.

Things I haven't written yet:
Inherent efficiency (kW usage) of system
Robustness of system (o2 availability/inverted leaching/solution equilibrium/media diversity)
Modular scalability
Use of DIY Air-Pots in D9s garden
Benefits of Perpetual gardens with the PPK

ImaginaryFriend's Grow Log Index

ImaginaryFriend's PPK Grow Index

ImaginaryFriend's PPK Grow Index

My interest in the Passive Plant Killer
Veg Pics of the Lady on the Right, Followed by the Lady on the Left
Pruning Strategy for Flower, flower day 5 pics
Flower Pics, Day 10
Flower Pics, Day 14
Flower Pics, Day 21
Flower Pics, Day 30
Flower Pics, Day 33
Flower Pics, Day 36

Things I haven't written yet:

Nutes/pH/Co2 levels
Humidity
Pruning/defoliating strategy/observed responses
Deliberate overdosing with P to increase stretch
My take on VPD, osmotic pressure vs. hydraulic pressure, etc.

09/22
Bulk (just topped off) EC 1620, pH 4.8
Root Zone EC 1720, pH 5.9
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Strech is strechy. Off the P trip. 50mL base, 50mL grow into 4.5 gal RO. Lighter than I want in N, very light in P... Need to get Jacks, but my OD on P should be more than enough, and no signs of N deficiency right now...

ImaginaryFriend's intro Delta9nxs' THREAD

ImaginaryFriend's intro Delta9nxs' THREAD

Delta9nxs' thread is HERE

His evolved design as of Feb 6th, 2011can be found by clicking these blue words.

You might consider working your way through the original thread as D9 is pulling down one ~16oz plant per week in a perpetual cycle. The entire garden, including his veg room, runs only 6kW of light (including his veg cycle.) As of May, 2011, His top harvest are closer to 23oz/plant.

Delta9nxs opens his thread describing his intentions as developing a "device that can only be described as a “non-circulating, stagnant, hydroponic, capillary wick plus capillary medium with root sump, evapo-transpirator”. Or possibly it will be known as the “passive plant killer”. That's it, the PPK device."

He spent considerable time and energy looking into passive systems, in an effort to find a viable way to grow plants and sleep at night.

His system has gone through a number of subtle changes, and he experimented with a variety of mediums.

-Since he introduced the system, he abandoned the 'capillary wicks' in favor of running just the 'medium wick'.
-He introduced an automated top feeding pulse system, which I talk about here.
-He is running Jack's Hydroponics at 3-1-4 for all phases of growth.

It's current incarnation (developed mid-May, 2010) consists of:

I. A five gallon pot containing prepped coco, with
I.A a bunch of 5/16 air holes drilled through it
I.B a medium filled "sump", or "wick", or "tailpiece"
I.B.1 with the base closed with wire
I.B.2 packed with the same grow medium as the root-zone-bucket.



II. A reservoir directly under the bucket.







The small PVC plug is an access point for D9 to check the nutrient characteristics... I think he uses something like a turkey baster.

Link to the "Fast-n-Cheap Method"

Eventually, to save on floor space, D9 transitioned to 3.5 gallon buckets with a hole drilled out their tops for the medium wick in the veg room. As you can see, the bottom reservoir need not be of a particular volume, so long as that volume's level is controlled relative to the bottom of the media (D9 refers to this space as the 'air gap').





In the image directly above, you can see a tire valve sticking out of the base of the reservoir. Delta9nxs currently plumbs all of his connections with 1/4 hose and brass tire valves with the needle removed. Pretty slick, simple and cheap. Link to Tire Valve Installation

III. A system to control the levels in the res below the root zone bucket. Any control reservoir will do, but here is his:



Link to Control Bucket Build and Details

I don't know if the images show it, but there is a float valve installed in the control bucket. That probably doesn't need to be said, but I said it anyway.

I'm running a two cell PPK. I have the float valve directly in one of the plant reservoirs, and bottom connect the two. Essentially, one of my reservoirs is my control res...

IV. A Bulk reservoir to feed the control bucket. D9 plumbs his bulk res to the control with the same inexpensive 1/4 line irrigation drip line (not perforated (obvious, right) but the stuff that you run to actual drippers available at most box outlets/hardware chains) that run from the control buckets to the individual plant reservoirs.



Thread Index

Why I'm using the Passive Plant Killer approach in my current grow...

Why I'm using the Passive Plant Killer approach in my current grow...

I was attracted to D9's system after loosing +/- eight months to failed rDWC efforts.

I was using the toxic pipe from N-G-W.com...

My first failed grow showed toxicity issues identical to everything in that thread, and my response was identical to all the other reports in the thread... but it hurts my heart too much to get into that right now.

My most recent failed grow went to shit the moment in reintroduced the N-W-G.com hose into it... and my responses were imperfect. The end result was another complete failure.

I was committed to running something predicable this time around, and was leaning towards a Drain To Waste coco grow.

Somehow I ended up on D9's grow, started making my way through it, and liked that he had managed to eliminate all of the problems (I had decided) were inherent in rDWC (and require work arounds), and side stepped the 'mess' of DTW.

I had an unexpected act of life that took me away from the girls for an extra long weekend. To be honest, I hadn't thought of wicks for about fifteen years and wrote them off as... I dunno... primitive? child's play? But fresh off the Passive Plant Killer thread, I was primed to shove some rope up the bottom of the pots, dangle it in some water, and hope for the best.

When I came back, they were good, and I had roots growing out the bottom of my containers.

That's when I built my two cell PPK and had the girls moved in there within a couple of days:

Variations in my build from D9's.

Variations in my build from D9's.

I didn't use the same medium wick details as D9. I salvaged 3" PVC and uniseals from the failed RDWC, and used those components. I also reinforced my tote's lids:





Then I lost my camera.

So you'll just have to imagine 3" PVC coming out the bottom of the bucket, and held in place by a Uniseal.

I used 14" zip ties to attach heavy black felt to the bottom of the PVC, and covered the top of the sump with the circular cut out of the same material in hopes of slowing root penetration into the solution reservoir.

Twenty six days of veg in the PPK, Through 30 days of flower

Twenty six days of veg in the PPK, Through 30 days of flower

Plant on the left, 26 days of veg in the PPK, Through 30 Days of Flower

Plant on the left, 26 days of veg in the PPK, Through 30 Days of Flower

Nice summary. I learned a lot from D9 as well. Great grower and that thread is a great journey of experimentation and learning.

Pulse Feed Tech

Pulse Feed Tech

D9 initially introduced a 'pulse feeding system' into his plants in veg to make sure that there was enough moisture/nutes within the media to promote sufficient root growth to take advantage of the moisture/nutes provided by the capillary action of the wick system.

He built a manifold out of PVC and drip lines, attached that to a small pump and controlled it's 'pulses' with a Cyclestat by GreenAir Products.



These drip lines run to the top of each plant, where direct nutrient solution is 'hosed' over the surface of the coco for controlled periods of time.

He initially chose introduce this only during veg, feeling that hydraulic redistribution would be sufficient for maintaining uniform moisture throughout the medium once the root mass was well established. His introduction and discussion of hydraulic redistribution starts here and continues throughout the page (and is definitely worth the read).

Observing positive results in the veg room, he eventually chose to include a pulse system in his flower room as well.

My thoughts on this: Capillarity action--or (essentially) the tendency of a fluid to climb upwards through a porous media--is the consequence of the interaction between the cohesive and adhesive qualities of a fluid in proximity to a solid.

Fluids have a tendency to adhere to surfaces, and hold themselves together. This holding themselves together ("cohesion") can be seen in pure water as it 'bubbles' above the surface of a container.

Gravity is pulling against this process, so eventually, in a given medium, there is a maximum height that a capillary action will draw a solution upward.

Pulse feeds wet the medium above its natural wicking height, and allow for a connection between the bottom of the medium and the top of the medium (particularly in coco) and encourage uniformity of wetness and solution concentration throughout the media.

And this is consistency and uniformity is good for plant growth.

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UPDATE, Sept. 22, 2010

OldOne has been documenting his wick based PPK here. In striving for simplicity, he found a fabric wick that would keep the top of his coco wet without the addition of a pulse feed. Recently, in prep for changing nute profiles, he flushed his system and found much higher salt concentrations than he expected. The discussion related to the pulse v. non-pulse (including D9s quick comments) can be found in OO's thread here.

Essentially, it changes the question from "Does a pulse feed work?" to "Why does a pulse feed work?"

Stealing content from my own post in that thread (after all, I'm still in the My Thoughts on This section), it seems to me that:

Solutions naturally seek equilibrium. Equilibrium is not instantaneous. There are many mechanical/electro-chemical factors involved. But, in practice, various solutions under various conditions take various amount of time to find equilibrium.

With a solid wall pot, all direct-to-atmosphere-evaporation is going to be off the top.

This will generate a hydraulic force drawing nutes upward.

If this evaporative draw is happening faster than the solution can reestablish equilibrium, the result will be a varied nutrient concentration, with the heaviest concentration at the top.

Somewhere in D9's thread, he noted this same characteristic: Namely, bottom fed systems tend to accumulated salts at the top, while top fed systems tend to accumulate salts at the bottom. (Maybe for different reasons--evaporation through the top, PWT drying out in a top fed system?)

A pulse fed PPK feeds from the bottom, but regularly moves the concentrated solution back into the media, mechanically 'mixing' the solution back together, contributing to solution equilibrium.

So... there's some thinking on the why of the Pulse Feed, in addition to the how.

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EDIT/UPDATE October 9th, 2010

Somehow, I failed to notice that D9 has increased his pulse feedings from a 'few ounces' up to six ounces every two hours and around the clock.

As of May, 2011, D9 has been pulsing 16 rather than six. Additionally, I have come to recognize that insofar as there is a hydraulic column from the lower reservoir to the upper media container, all soluble elements will move towards equilibrium regardless of whether the pulse water directly washes into the lower res or not.

We may now have slightly differing positions on the application of the pulse feed.

Here's why I think that: Member jjfoo proposed a version of the PPK wherein an electronic level switch would trigger a pulse feed to maintain the Air Gap level in the bottom bucket (here). This is similar to some interesting design efforts for a non-electric method of managing sub-irrigation solution levels that were discussed before D9 adapted the timed pulse as a systematic approach.

I, in some manner, tried to suggest that this approach created more challenges then solutions. A few posts later, I suggested that jjfoo build out something that was very PPKish and then experiment in isolation with his flood/wick system in a few separate cells. If you're interested in following my critique, it can be found in the few pages following the initial link above.

If you do so, you will see that D9 followed up my analysis with a different one (here). It appears that his system is now actively pulsing enough solution to 'remix' residual salts and actively drain them back into his individual plant-reservoirs. Which means he is actively moving solubles out of the media into solution, which is something I am systematically trying to avoid.

I speculate that the roots exude sugars to feed microbiological elements (that may or may not populate our systems)... because that is what plants do. Maybe they do so at different points from different root structures, and maybe there is a sentience/bio-response that dictates this behavior, but I'm not sure I want to talk about that. That said, I do think there are sugars in the media as the result of basic plant biological activity.

I want them to stay in the media, and not get flooded into a solution as that would trend the nute-soup towards anything other than a 'pure' feed source (as haphazard as my approach to 'pure' has been)... especially if that flooding would generate a better environment for microbiological elements.

So D9 pulses with a high enough volume to remix his solution.

I pulse with less simply hoping to manage the solution distribution and equilibrium of those elements already in the media.

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On the same page, D9 tossed out this sweet link:

anyone who hasn't read the andrew olley presentation and grows in coco should read this.
http://www.iasa.co.za/downloads/symp...ew%20Olley.pdf

Click to expand...

One of the things that caught my eye in the summary of the presentation is that emphasizes that increased watering demands are matched not by increased volume but by increased watering frequency. (This is how I've been managing my pulse feeds. Not based on something like Olley's techical experience, but because I drilled all the way to the bottom of the buckets and larger volume pulses=puddles.)

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Which brings me to a FINAL NOTE: The methodology one might employ for pulsing demands slightly different construction details around the base of the media bucket. If you 'overpulse' you need to capture and drain that 'overpulse'. Stacked buckets are no problem. My reinforced plywood is...

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UPDATE OCTOBER 11, 2010 Here's some interesting tech I somehow overlooked my first few times through the thread... you can see that my buckets do not have this incorporated.

D9's POST 613:

Then we come to pulsed irrigation. Not only are the benefits of drip realized, but you also get the “plunger” effect. This sudden burst of water creates a wavelike effect that travels through the medium with a higher mass per application than drip, pushing and pulling more oxygen via displacement as it falls. This is why I did not drill out the upper half of my buckets. Gases cannot escape from the sidewalls of the upper half. As the pulse hits and falls old air is pushed out through the holes in the bottom and fresh air is drawn in through both the top of the medium and the sidewall holes.

Click to expand...

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Sump, better known as Medium Wick Tech

Sump, better known as Medium Wick Tech

D9's initial designs utilized fabric wicks in addition to a central medium wick. (He also used turface as his medium. Post 8 has Haps asking, "What or who is turdface?" I read the description, but have never seen it. Apparently, when wet, it is heavy.)

He decided that fabric wicks were unnecessary. I'm not sure if he scratched his head for a while while perusing tombs of knowledge, or just said, "Fuck it, I'm done with these."

(What he actually reported was: "i prefer the media wick as it seems to be working fine and i believe the cloth wick kept the bottom of the container a little too wet. not enough to cause rot or damage, just wetter than my experience tells me is good for cannabis." p.184)

Regardless, his decision was formative for my understanding of the tech related to the PPKs. (OldOne microgrows with a fabric wick in his PPK. As I write this, he is documenting his grow here. WARNING: My drivel has polluted his thread too...).

FOR THE RECORD: OO's second run with his PPK is based on a media wick. That grow is documented here.

Now the first thing that happened as a consequence of his system is that he removed PWTs from his root mass. What's that you say?

Quoted by D9 in post 49 of the PPK thread:

"There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .125 (1/8) inch.. This is water that occupies a layer of soil that is always saturated & will not drain from the portion of the pot it occupies. It can evaporate or be used by the plant, but physical forces will not allow it to drain. It is there because the capillary pull of the soil at some point will surpass the GFP [Gravitational Flow Potential, or a description of the interactions between cohesive and adhesive relationships between solution and media within the system as it relates to gravity] therefore, the water does not drain, it is "perched". The smaller the size of the particles in a soil, the greater the height of the PWT.

If we fill five cylinders of varying heights and diameters with the same soil mix and provide each cylinder with a drainage hole, the PWT will be exactly the same height in each container. This saturated area of the pot is where roots seldom penetrate & where root problems frequently begin due to a lack of aeration. Water and nutrient uptake are also compromised by lack of air in the root zone. Keeping in mind the fact that the PWT height is soil dependent and has nothing to do with height or shape of the container, we can draw the conclusion that: Tall growing containers will always have a higher percentage of unsaturated soil than squat containers when using the same soil mix. The reason: The level of the PWT will be the same in each container, with the taller container providing more usable, air holding soil above the PWT. Physiology dictates that plants must have oxygen at the root zone in order to maintain normal root function."

The media wick provides a predictable level for the PWT, and as we manage the 'air gap' between the base of our root mass zone and the solution we can insure that this PWT does not drown our roots. As various stuff have various capillary capacity, using our media itself provides us with the capacity to control the level of the PWT, where as fabric wicks might bring more solution into our root mass than we'd otherwise choose.

Intuition suggests that to maximize our passive solution penetration, we ought to keep our PWT as close to the bottom of our buckets/containers without actually bringing the PWT into them.

So that's why the PPK usually uses media as a wick, and the level of the solution below the root zone bucket is important.

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May 10, 2011: The 'tailpiece' should be understood on the one hand as a media wick, and on the other, a 'sump' allowing the pwt to sink below the primary root zone.

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so this is what you've been up to! i was very pleasantly surprised. thank you very much.

getting the word out about this extremely reliable method could help a lot of folks successfully grow their own medicine.

and for those who wonder whether this device is capable of growing a large plant here is my largest to date. this plant yielded 521 grams or 18.38 oz's.

thanks again! you have made my day!

later, d9

D9:

getting the word out about this extremely reliable method could help a lot of folks successfully grow their own medicine.

Click to expand...

Hopefully.

I haven't really talked much about the environmental conditions of my grow, but my girls in the PPK have withstood:

-Temps ranging from 73-110.
-Bulk reservoir temps of 104.
-pH fluctuations from 4.3-7.0.
-Sketchy nute regimes.

And appear to be doing better than okay.

All the while I have a 1/2HP chiller sitting on the shelf beside my bulk reservoir, and 1000cfm worth of fans boxed below it. It was not my intention to test the robustness of the system with extremes in conditions... but... shit happens. And the girls are okay.

The PPK is a relatively fast, relatively productive and very buffered approach to growing. And that is a good thing.

*D9 has brought every plant to harvest since he started developing the PPK.*

Jeeze IF, when you threaten to log a grow you dont kid around do you? Fantastic job man.

Eagerly subscribed...
OO

OO:

Jeeze IF, when you threaten to log a grow you dont kid around do you?

Click to expand...

That's right.

Glad you found it, oldone.

ImaginaryFriend said:

Glad you found it, oldone.

Click to expand...

Found it? You practically led me here by the nose, LOL. But then again I would have been seriously pissed if you hadn't.

See, now you have something to do and wont be so bored as before. And I thought of something else. Do you have a webcam in your room? If so, I can show you how to do daily timelapse movies which are very informative and cool to watch.

Later,
OO

OO,

OO:

Found it? You practically led me here by the nose, LOL.

Click to expand...

Hey, sometimes people need a bit of guidance...

You've mentioned your timelapse movies before, but I haven't stumbled across one yet... links? Didn't you mention that your plants tend to start to droop just before lights go out?

ImaginaryFriend said:

Hey, sometimes people need a bit of guidance...

Click to expand...

You got that right...I dint follow the grow logs because I'm too lazy to write a proper one.

ImaginaryFriend said:

OO, You've mentioned your timelapse movies before, but I haven't stumbled across one yet... links? Didn't you mention that your plants tend to start to droop just before lights go out?

Click to expand...

I cant post them here and wont to public view. Way too paranoid for that. Ordering Jack's was a big deal for me.

They definitely droop the last couple of hours. They look like they are wilting. Always by next lights on they perk right up and look great. I was making 640 x 480 videos. I take a pic every 2 minutes then process them into a xvid avi. Its fascinating to watch. I wish I could attach one to a PM. A useful diagnostic tool any tinkerer should at least try out...

See ya,
OO

I think a library of those videos running side by side could really be a useful measure to identify plant reactions to environmental and nutrient changes.

I've been thinking about the day I can integrate that into some other tracking/documenting automation I would like to develop.

Gotta run. I'll catch you later.

Pruning Strategy for This Run

Pruning Strategy for This Run

My tent is 42"x48" with a little extra room in the back corners.

As I am growing out just two plants I have an awkward rectangular space to train the girls into.

When I saw full maturity on the shade leaves (i.e. sevenish inch eleven fingered leaves):



...and hit the minimum height I hoped would get my top colas into a nice position relative to the second 600W in the cool tube stack, anticipating slightly less than a 2x vertical stretch, I flipped 'em. I wouldn't have mind vegging a bit longer, but obligations down the road said I'd better get this started.

My canopy goal is to have light penetration throughout the front of the plant to hit the back structure. This is kinda the reverse of most vert SCROGS, where you see the back foliage stripped in favor of training everything to the front. I didn't feel that this conventional approach was the best choice in this garden, 'cause the front of my canopy grows into the cool tubes every day.



In general, I've been using the tomato cages to train lateral growth, well, laterally. I've been thinning selectively thinning the interior growth (mostly on the 70% of the pant closest to the light to allow for more penetration). I've been trying to anticipate where there will be conflict within the branch structure, and be proactive about eliminating it. The portion of the plant closest to the light has been getting quite a bit of not-so-Low-Stress-Training.

In another deviation from my norm, I elected to really jack up the P levels in my nutes at the same time I flipped in hopes of promoting stretch. It appears to be working. My canopy is opening up, light penetration is going deeper, and I seem to be getting my target canopy dimensions for where I'm at in the flower cycle.

Five Days into Flower:



These pics are starting show the rectangular training I'm shooting for:



I've been pretty aggressive on thinning primary shade leaves, mostly getting them before they are even developed half way. I am not trying to restrict stretch from the sides and the back, as I'm hoping that growth will wrap around and over.

I'd say: So far, so good.

As always, I'm very happy with the PPKs.

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