DIY Air Pruning Pot Experiment - Pictures

[Hobbes]

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There are eight options to force a root system to branch:


1) Herbicide -- One example has herbicide pellets sewn at intervals within a fabric. Root-tips that contact the herbicide die, causing branching to occur behind that point.


2) Copper -- Copper is painted on the inside of a plastic container. The copper is toxic to roots, so root pruning occurs. Misuse of copper can be toxic to humans and the ground, so extra care should be taken when using these products.


3) Mechanical root pruning -- Large trenching-type machines can chop roots of field-grown trees, which causes branching behind this cut. The trees are then dug, balled and burlapped. Some nurseries partially hand dig a few months before harvest to promote root branching. The open wounds of the cut, however, may allow pathogens to enter the plant.


4) Root suffocation -- Roots growing in containers with water reservoirs in the bottom are pruned when the roots hit the open water.


5) Air-root pruning -- Directing roots to air openings causes the root-tip to dehydrate and forces roots to branch behind this point.


6) Root constriction -- Roots can be forced to branch behind a point of constriction while trying to grow through a fabric.


7) Root-tip-trapping -- Roots can be forced to branch behind a point where the root-tip is snagged sufficiently enough to impede growth.


8. Light -- Some fabric containers root prune by a combination of light and air.

http://www.sportsturfonline.com/ME2/Audiences/dirmod.asp?sid=&nm=&type=Publishing&mod=Publications%3A%3AArticle&mid=8F3A7027421841978F18BE895F87F791&tier=4&id=94F330357D4648C3A605E2A323E83F9A&AudID=AC361F5928F54864BFCBBD93E5B8624D

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[Hobbes]

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Air-pruning Containers -- the key to growing trees best suited to urban spaces is to maintain most roots in a horizontal position with continued branching. This can be accomplished by allowing air to prune the roots as they first reach the bottom and later the sides of the growing container. The dead root-tips have effectively been cauterized and are unlikely to be colonized by pathogens. Young seedlings respond by developing fibrous absorbing roots laterally in the container. Effective air-root-pruning containers guide root-tips into the numerous openings without having openings so large that rapid evaporation and salt accumulation become an issue. Repeated pruning on the bottom, as well as the container sides, helps the tree develop a vigorous and efficient root system.


Root-tip trapping - involves fabric containers. Root pruning is accomplished as the root-tips contact the fuzzy inside fabric and can no longer extend. The trapped root-tip will typically stop elongating, become pudgy, and then lose hormonal control over root development, resulting in secondary branch roots. The advantage of this root-pruning technique is that the roots do not circle, no water is lost through the container sidewall, and roots are fully contained -- even when the container is in the ground or snugly inside another container. When used above ground, the insulating value of such fabrics reduces root zone temperatures by about 20 degrees Fahrenheit. This allows root growth on the side of the container exposed to sun, and avoids the problems that arise when roots are killed by absorbed heat.

Root girdling or constriction pruning - is effectively accomplished in field soil where roots are allowed to grow through a fabric container wall. Young root-tips extend freely through the fabric, but as soon as they increase in diameter ever so slightly they become girdled. Because the roots are young and actively growing, secondary root branching occurs in a similar manner to air-root pruning or root-tip trapping. In other words, the choking causes the root to lose its apical dominance and lateral branching or pruning occurs inside the bag. In the ground the roots function outside the container wall and absorb water and nutrients which are transferred to the leaves via the central xylem tissues. However, the constriction prevents the downward movement of sugars from the leaves from going beyond the inside wall of the fabric. This accumulation of sugars causes nodules to form that have many root buds. When the tree is harvested and the fabric removed, robust root growth appears from the nodules.

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I'm going to research trapping and constricting, seems easier to convert pots. And no holes in pots. I'm thinking of some kind of Brillo Pad like liner for buckets.

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**edit: It didn't take long to find.


RootTrapper® Pot-in-Pot Insert.



Now available to custom fit your socket pot. Major root escape is no longer a problem plus a fibrous root system is created by root-tip-trapping. At harvest, roots are insulated from temperature extremes.


http://www.rootmaker.com/system_aboveground.php#jump

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Does anyone have experience with trimming the root ball? Will new root tips form on the old roots or with they branch and new tips from the branches? If we can get branching we can just pop the root ball and score it.

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[Hobbes]

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Does anyone have an opinion on a good root trapping fabric until we can order proffesional liners, if we ever do? I was thinking a couple layers of Landscape fabric.

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Landscape fabric is a synthetic material that may be either woven or perforated throughout with tiny holes. Its main function is to block sunlight from reaching weed seeds and young sprouts to prevent them from germinating and growing while still allowing air and water to penetrate through it into the soil. Landscape fabric can be used around new or existing landscape plantings. It can also be an effective means of controlling erosion.

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[Hobbes]

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I transplanted and repotted a half dozen plants tonight, using 3 different techniques to promote root branching.

1. Air Pruning

I drilled 1 1/2" and 1/4" holes in this 5 gallon bucket then lined it with 5 layers of fiberglass screen. I'm hoping the 5 layers of screen keep more moisture in and work for both constriction and trapping.

Thanks to OneEyedWilly I just put my air pruning bucket inside another bucket when I want to keep more moisture in. This plant is a Strawberry Cough.

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2. Root Trapping

I picked up two types of landscaping fabric, one that is a thin sheet with tiny holes (constriction) and the second a thicker woven mat (trapping). This first one is the thicker woven fabric, much easier to work with because it hold it's shape. This one has my best hopes for a liner for our existing buckets. The fabric is tightly woven on one side and loser on the other - loose side on the pro mix / roots side to give the roots a path in, tight side toward the bucket to stop circling the bucket behind the fabric.

I repotted a Bubblegum clone in this picture. I roughed up the root ball a bit, tearing out the circling roots.

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3. Root Constriction

This fabric is very thin and slick with tiny holes. I'm hoping that the roots go through the holes and the constriction forces branching behind the constriction. I have concerns about this fabric because the holes might be too small for the root tips to go through. And it's pushed up against the bucket wall, the roots will have to go in the hole to circle the bucket - if there were pro mix behind the fabric it would make the roots going through easier.

This is my only Jack The Ripper pheno, I don't think I'll keep it so I don't mind beating it up a bit. I had a runt from a double shoot seed that made the whole grow room smell of lemons, this one just has a mild lemon smell. I'll have to see how the high is in another 2-3 weeks when it's cured properly.

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I'll give the plants 2 or 3 weeks then pull the root balls and take a look.

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[That 5hit]

Prices .

 

[Hobbes]

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3' x 50' roll of each:

Black constriction fabric: $4.99

Gray root tip trapping fabric: $24.99

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http://www.canadiantire.ca/AST/browse/2/OutdoorLiving/GardenAccessories/GrassCollectionLandscapeFabrics/PRD~0591726P/Platinum%252B400%252BWeed%252BBarrier.jsp

http://www.canadiantire.ca/AST/browse/2/OutdoorLiving/GardenAccessories/GrassCollectionLandscapeFabrics/PRDOVR~0591891P/Landscape%2BFabric.jsp

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[Don Gin and Ton]

like the new bigger holes pot but i think you'll find the roots will grow round like if the pot didnt have holes. cant wait to see the results of all of these

 

[Hobbes]

subbed for the ride hobbes

ill post up my airpot comparison in this journo if thats kool with you !?

Absolutely. Post all the pics and info you can, everyone else is welcome too as well.

Open thread on developing root systems.

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"like the new bigger holes pot but i think you'll find the roots will grow round like if the pot didnt have holes."

5 layers (6 with overlap) of fiberglass screen makes a pretty solid barrier, I think there will be little evaporation as well. I might get lucky and get some root constriction or tip trapping, but the screen is fairly smooth. Landscaping fabric would be a better choice for an air pruning bucket I think.

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[Don Gin and Ton]

i really dont think youll have any problem with evapouration at all. my side by side with a normal pot has been on par with its water requirement to the airpot one. might be different with the flat sides but i doubt it.

the solid barrier is what makes m think the roots will go round like a normal pot the trumpets on the shop bought airpot force the roots straight out but if it goes out and hits a smooth round the pot screen it will inevitably go round!? well thats my thinking but i hope to be proved wrong.

 

[Hobbes]

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"the solid barrier is what makes m think the roots will go round like a normal pot the trumpets on the shop bought airpot force the roots straight out but if it goes out and hits a smooth round the pot screen it will inevitably go round!?well thats my thinking but i hope to be proved wrong"

I think you'll be right. The threads in the screen seem waterproof and they're overlapped and pressed to the bucket wall by the pro mix.

In a couple of weeks I'll pop the root ball, if I've got circling I'll switch the fiberglass screen with the woven landscaping fabric.

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[That 5hit]

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"the solid barrier is what makes m think the roots will go round like a normal pot the trumpets on the shop bought airpot force the roots straight out but if it goes out and hits a smooth round the pot screen it will inevitably go round!?well thats my thinking but i hope to be proved wrong"

I think you'll be right. The threads in the screen seem waterproof and they're overlapped and pressed to the bucket wall by the pro mix.

In a couple of weeks I'll pop the root ball, if I've got circling I'll switch the fiberglass screen with the woven landscaping fabric.

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i was also thinking this
maybe less layers would work better
like a 2 layer
i'm thinking in order for this to work the dirt ,roots and fabric has to breath
the trumpet shaped hole of the store kind allows the roots and dirt to breath freely- unlike the cloth kind that is pressed againest the soil- so if the coth used is thinner the roots will hit the air given a more same effect like the trumpet kind - so use the buckits with the holes init then use 1 or 2 layers of Landscape fabric to keep the soil from falling threw the holes

 

[norcalikilla]

i have got to say this is probably the sickest thread on here. getting down to the science of why some ppl get lucky with huge buds while being inexperienced growers by mistakingly taking better care of roots is genius. now we can make it possible for all to know how to take care of their plants correctly and move the connosoir community forward!

ok enough rambling. but really thanks again for posting this experiment! you could've done this at home and not said anything so when i say thanks please know that i mean it sencerely. i did have an idea for you if after a few days/weeks you get root circling. try taking a metal skewer or possibly wood and pokeing 3 holes in each of the 1.5" holes about 45 mins after watering. what this will do (in theory) is create the tunnels that the store-bought-wrap will have so that when the roots just happen to hit the tunnel, it follows it toward the air for prunning.

you can see that the reason the roots dont circle in the store bought wrap is because they CANT. once they reach a tunnel, they have no imput in the direction they grow in. forward is their only option. thats where i grabbed 45 minutes from. the water will make the soil soft enough to penetrate easily (as you will have to do this many times haha) but after the water flows down and the dirt drys out it will semi-harden to the shape made by the skewer.

i hope this is a contribution and if not dont be afraid to criticize. i like criticism because it helps me see things another way and negativity doesnt bother me much

 

[Hobbes]

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"i did have an idea for you if after a few days/weeks you get root circling. try taking a metal skewer or possibly wood and pokeing 3 holes in each of the 1.5" holes about 45 mins after watering. what this will do (in theory) is create the tunnels that the store-bought-wrap will have so that when the roots just happen to hit the tunnel, it follows it toward the air for prunning."

That is insightful.

I was thinking: "poke a hole in my screen!!! AAAAHHHH ..... wait a minute ... a path for the root tips to follow to their death!!"

Huge KUDOs norcalikilla!

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[norcalikilla]

i think the kudos are due to you as well. thanks for the experiment. i cant wait to see how this all turns out and hope that you blow that expensive plastic wrap right out of the water!

nck

 

[That 5hit]

i think the kudos are due to you as well. thanks for the experiment. i cant wait to see how this all turns out and hope that you blow that expensive plastic wrap right out of the water!

nck

yeah gr8 info and welcome RIU
you get my +rep

 

[Airwave]

I've been using Airpots next to regular pots for my entire grow. My plants are due to be harvested any-time now and I see no difference.
Also, watering those Airpots can get a bit messy.

 

[That 5hit]

I've been using Airpots next to regular pots for my entire grow. My plants are due to be harvested any-time now and I see no difference.
Also, watering those Airpots can get a bit messy.

i dont think the point is to see a defferance more or less
but a healthyer life
not really meaning bigger better buds but trying to incress the liky hood of a plant staying healthy threw out the grow and not feeling the effects of rootbound and other root issue

 

[Hobbes]

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I'm repotting all of my younger plants that are in flower and 1 five gallon bucket in veg, lining the buckets with root trapping woven landscaping fabric. This one is a Skunkberry from Peak.

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I popped the root ball and it was solid.

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Some circling on the bottom.

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I skuffed up the root ball to stop the circling. I attached the bucket rim and the fabric with masking tape, to keep the liner in place while repotting.

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I'm keen on seeing how this landscaping fabric works for root trapping, it could make life real simple for us.

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[That 5hit]

i really hate that you can only +rep a person once

 

[norcalikilla]

speaking of which i thank you sir. i dont really know wat that is or how to do it but i think its a good thing.

hey hobbs do you water roughly 8hrs to 24 hrs before you transplant to prevent shock? since i always do i dont know wether or not you need to. i kind of air on the side of caution when it comes to this kind of thing and i feel like stress would be a good thing... however shock is not. i guess im just in search of the line between positive punishment and harassment hahaha