Root Pruning containers, experience (and ranking)

Hello all!

I've not ever posted in this portion of the forum before, but I lurk from time to time.

In my response to Paul and Alan's giveaway thread, I mentioned that I have 28 pawpaw seeds planted in RootMakerII pots. I've only grown one other Pawpaw from seed and it was also in a RootMaker pot. It has been truly remarkable!

For those on the forum who aren't familiar with Pawpaws, they have a very long taproot, and often times with seedlings the rule of thumb is that the taproot is at least two times are "tall" as the trunk. However, with the RM system I've managed to get incredible secondary and tertiary root growth on my specimen grown from seed. I will be moving it from a 1-gal to a 3-gal pot as soon as the 3-gal container comes in.

This isn't my first foray into airpruning containers; I've used several DIY styles before. These include a fabric pot, a fabric tote repurposed to a plant container, and 5-gal buckets with holes drilled in the sides and bottom. My rankings from personal experience are as follows:

1. RootMakerII
2. Fabric Pot
3. 5-gal Bucket w/ Holes
4. Fabric Tote

I rank them as such because the fabric tote didn't last at all under the hot Texas sun (was living in Killeen at the time), while the 5-gal buckets proved to be excellent tree containers (still have a number of named Pawpaw varieties in these guys) but there was not nearly as much effective root pruning in these containers compared to the purpose-built fabric pots or the RootMaker injection-molded pots (which certainly take the cake thus far).

If you are not familiar with air pruning roots, it is the method of forcing root tips to hit air, dehydrating the tips and causing root branching. This provides more surface for small, hair-like feeder roots to grow and encourages a really strong root system that is better able to absorb water and nutrients, leading to larger and healthier plants. Or so the theory goes. In my experience, I have noticed really good root ball growth, but have not noticed much difference in terminal size of the plants.

Has anyone else used root pruning containers, and how would you rank their efficacy?  

Julio,

I have never worked with the RootMaker, but I have tried out the Air-Pot containers to learn more about how air pruning works. The Air-Pots seemed to work quite well for the few things I have grown in them so far.

I've never had the opportunity to use them on a large scale, so I would be interested to hear a comparison from someone who has worked with both the RootMaker and the Air-Pot on a larger project.

Alan,

That is an interesting idea. I could do plant another round of pawpaw seeds in air pots next year and compare them to those I started in RootMaker pots this year.

Well, after giving some more thought to Alan's post, I ordered 10, 1-gallon AirPots to plant another round of pawpaw seeds in order to compare their growth to that of the RootMakers. While this will not be a direct apples-to-apples (or rather, pawpaw-to-pawpaw) comparison due to the relative age of seed stock used (those planted earlier in March were leftovers from a purchase made in the spring of last year and kept in the refrigerator, while those planted into the 10 AirPots were freshly ordered from Baker Creek Heirloom Seeds sometime in the past few weeks). However, Baker Creek actually puts 7 seeds in each package, so after planting in the 10 AirPots I had four left over to place in 1-gal tallboy tree nursery pots to act as a quasi-, if admittedly small, control group.

Anyway, I planted these 14 today, about 2 weeks after the first round consisting of the year-old seeds.

For this informal test, I intend to:

Note the sprouting dates for each group.

Monitor their progress against one another and compare overall vigor throughout the year.

NOTE: As of now both groups are isolated from one another, but both are in shade. I plan to move them all to a concrete pad and construct a shade tent for them so that they all receive the same shaded light through the remainder of the growing season.

Monitor fertilizer use and generalized observations on water usage.

Take measurements throughout the year with a 2-week stagger to account for the difference in sowing dates.

As noted above, this may not be exactly scientific, and the two test groups are both 1)small in size and 2)do have notable differences between them, but it will be an interested look at what differences, if any, these two styles of root pruning containers express when used to grow Pawpaw from seed, with the conventional tallboy-style tree pot for comparison's sake.

So, yeah, stay tuned!

March 21: Planted 27 "packed for 2018" Pawpaw seeds in 1-gal RootMakerII Injection-Molded Air Pruning Containers (RM)

April 10: Planted 10 "packed for 2019" Pawpaw seeds in AirPot 1-gal Air Pruning Containers (AP)

April 10: Planted 4 "packed for 2019" pawpaw seeds in 1-gal tallboy-style tree nursery pots (TB)

May 20: RM seems to be thirstier than AP; this could be due to the differences in location (North facing vs South Facing). No seedlings have broken the surface, though I can see some root growth along the air pruning holes of the RM

June 7: First pawpaw seedling emerges; RMII pot

June 10: The RM pots now have three seedlings; AP and TB have none

If you are interested in air-pruning you should check out RediRoot, in the interest of full disclosure, I work for them but I have honestly seen some amazing results and they offer so much aeration and air-pruning power. RediRoot

Jeni Lee wrote:If you are interested in air-pruning you should check out RediRoot, in the interest of full disclosure, I work for them but I have honestly seen some amazing results and they offer so much aeration and air-pruning power. RediRoot

Thanks for the suggestion. Maybe next year... I've already got my hands full with 41 seeds planted, as this is all being done at my house (in the middle of the city) and space is an issue for me.

But, if you wanted to talk to the powers that be to donate 10 or so RediRoot pots for comparison, I'd be more than happy to oblige!

Hello everyone!

Just a few updates to make:

RM seems to be thirstier than AP; this could be due to the differences in location (North facing vs South Facing)

I plan to move the pots under a shade tent the weekend following Memorial day

No seedlings have broken the surface, though I can see some root growth along the air pruning holes of the RM

Additionally, Jeni Lee has kindly provided me with a few samples of RediRoot 1-gal air pruning pots as well as a couple of larger fabric air-pruning pots to experiment with on next year's seedlings. Thanks, Jeni!

Here is a youtube explanation of a commercial air pruning pot.
https://www.youtube.com/watch?v=NWMHMg--wiE

Kai Walker wrote:Here is a youtube explanation of a commercial air pruning pot.
https://www.youtube.com/watch?v=NWMHMg--wiE

Yes indeed, that is how they work!

Julio Budreaux wrote:

Kai Walker wrote:Here is a youtube explanation of a commercial air pruning pot.
https://www.youtube.com/watch?v=NWMHMg--wiE

Yes indeed, that is how they work!

Mine are just hole drilled.
If they do not air prune then they at least let in more oxygen. Either way a cheap method and a benefit to the plant.

Kai Walker wrote:

Julio Budreaux wrote:

Kai Walker wrote:Here is a youtube explanation of a commercial air pruning pot.
https://www.youtube.com/watch?v=NWMHMg--wiE

Yes indeed, that is how they work!

Mine are just hole drilled.
If they do not air prune then they at least let in more oxygen. Either way a cheap method and a benefit to the plant.

I agree, and have ranked 5-gal buckets with holes as the third best option I have used prior to this test. I have little-to-no indication that the holes actually did provide air pruning, but as you said the increased oxygen to the root system has shown no harmful effects while being cost-effective at that size. It is worth noting, however, that 2-gal buckets are roughly equivalent in price to some of the commercially-marketed air pruning containers discussed in the post.

Thanks again for your comments!

Julio Budreaux wrote:

Kai Walker wrote:

Julio Budreaux wrote:

Kai Walker wrote:Here is a youtube explanation of a commercial air pruning pot.
https://www.youtube.com/watch?v=NWMHMg--wiE

Yes indeed, that is how they work!

Mine are just hole drilled.
If they do not air prune then they at least let in more oxygen. Either way a cheap method and a benefit to the plant.

I agree, and have ranked 5-gal buckets with holes as the third best option I have used prior to this test. I have little-to-no indication that the holes actually did provide air pruning, but as you said the increased oxygen to the root system has shown no harmful effects while being cost-effective at that size. It is worth noting, however, that 2-gal buckets are roughly equivalent in price to some of the commercially-marketed air pruning containers discussed in the post.

Thanks again for your comments!

You're very welcome!

I can get cheap used plain food grade 5-gal buckets with lids at walmart bakery for 2 for $1.00 !
I may make more of those pots. But it takes 2 hours to make one
None of that counts the cost of the potting mix or the plant nor having to water it more than a regular garden.

My theory is that even if the roots didn't air prune it would increase available surface area to the plant.
And that in turn should help.

Won't know until the end of the growing season.

Had them last year but it was so hot and humid that most plants didn't survive no matter how much water we gave them.

Air pot pruning doesn't work when humidity is high and temps high either.

I started thinking about  making a contraption that could easily turn a regular throw away  garden pot into something with all those outward facing cone shaped holes that guide the roots to being pruned so effectively, and something that pokes all the holes from the inside, and the first easy idea was a board with lots of nails driven through, which evolved to drywall screws, then the wood turned to metal, and the screws became machine screws with nuts, ,

With a simple flat apparatus  the operation would be easiest on a flat surface which would mean  cutting off the pot bottoms and putting a slit down the sides, then reassembling them, possibly keeping the hole thing heated to sort of melt its way through

But that seemed like too much work and extra materials,  then  the other day I was talking with a mechanic after thinking about some kind of lever action that would allow two of these spike assemblies to push out from a center pivot as the whole thing was driven down, making holes on both sides of the pot at once and he suggested a brake shoe assembly which could be easily salvaged ( I have lots of junk cars, ) and have two pieces of metal (shoes), as well as a center assembly and hydraulic operation..

In thinking further about it, maybe the shoes could be the best part of the  contribution, since they already have the circular shape, as well as mounting brackets on the inside that could easily accommodate any other sort of force application/conversion.

Anyway, I saw this post  and wondered if anyone else has thought about this  or constructed some apparatus (failures just as valuable as successes) before I get busy and actually start working on the project.

I'm a fan of Akiva at twisted tree farms.  I've had my eye on this method for a while but haven't done it yet.

Kai Walker wrote:I can get cheap used plain food grade 5-gal buckets with lids at walmart bakery for 2 for $1.00 !
I may make more of those pots. But it takes 2 hours to make one :-(

Now THAT is a deal! Whenever I've made them it's only taken me about 5 - 10 min per bucket. What system are you using?

bob day wrote: I started thinking about  making a contraption that could easily turn a regular throw away  garden pot into something with all those outward facing cone shaped holes [...]
Anyway, I saw this post  and wondered if anyone else has thought about this  or constructed some apparatus (failures just as valuable as successes) before I get busy and actually start working on the project.

No, I've not ever thought of something like that. I'd be interested in seeing a prototype if you were to put one together!

Scott Foster wrote:I'm a fan of Akiva at twisted tree farms.  I've had my eye on this method for a while but haven't done it yet.

I had a bed almost identical to those shown in the video at my last house and attempted to grow spinach and arugula in them. They were INCREDIBLY hard to keep watered (too much exposed surface area in my hot climate) and the spinach died from lack of water, while the arugula bolted early and became far too peppery for my tastes. Perhaps something like zucchini or strawberries would do better, but keeping them watered would continue to be a struggle for me here in Central Arkansas. Besides, I gave up on zucchini (vine borers are really bad around here and I don't use pesticides, so it's a losing battle for me) and my strawberries seem to be enjoying their hugelbed just fine.

Update

May 30:

I had a few weed seeds that sprouted from my compost in two of my RM pots, and when I pulled them out I figured I'd check on the pawpaw seeds in those pots, as they should at least have grown a sizeable taproot by this point. They were both duds. :( I knew it was a longshot with the seeds from last year (pawpaw seeds don't hold well) but I'm keeping my fingers crossed for the rest of the bunch.

Nothing to report on the AP or TB.

Without knowing what you have said so far about your paw paw sprouting technique, I will share what I was told by the local grower who sells both seedlings and full grown trees.  

Paw paws were meant to be planted by being eaten by a ground sloth- now extinct, and therefore need to be heavily scarified.  Today I think deer do a pretty good job, followed by all the other critters that share them. Maybe some of the special varieties don't need that as much, but another thing a neighbor found was that seeds put in the ground would sometimes wait several years before sprouting, in that her rental tenant used to play with them, and after he was gone for years she suddenly started to have paw paw trees appearing.

None of that is proof conclusive that your paw paw seeds might still have a chance, but I would at least put them someplace where if they did suddenly decide to sprout they could stay and grow.

I watched the video Kai posted here: Rootmaker video and it led me to the Rootmaker site.  Im impressed and I have to say that the pots sure look like they would promote excellent root growth.  I'm going to do some experimentation next year.

i buy the cheap 3 and 7 gal containers 75cents i think for 7gal
i use a knife to make several slits through the sides.
has been working well except they seem to need water a bit more often

its summer now, and i am in New Orleans (90s temps)
black containers can bake soil....
i often paint them white, and even double them up.
or place several next to each other and mulch on top.

This is what I like about the Rootmaker pots:



It sure looks like it would be the most effective way of training roots.

Timothy Markus wrote:This is what I like about the Rootmaker pots:

[...]

It sure looks like it would be the most effective way of training roots.

Yeah, those injection-molded cells certainly look like they would do a good job, but I have been pretty disappointed with them.

The blow-molded cell-trays have given me better results for starting seeds, and I've had really good results with the 1-gal pots for many other plants (three mulberries, four fig cuttings, a western soapberry, and two echinacea). Pawpaw are just difficult to sprout, but I knew that going in.

I thought you ranked them #1.  Were you talking about something else?

Timothy Markus wrote:I thought you ranked them #1.  Were you talking about something else?

Yes, I was talking about the 1-gal Injection Molded RootMakerII pots; I don't consider the propagation cells to be "containers" so I didn't include them in the ranking system.

This is the 1-gal injection-molded RM pot (7.5" Height; 6.5" Inside Top Diameter; 7" Top Diameter.  Volume - 190 cubic inches):



here are the injection-molded propagation cells (Cell Dimensions - 3.125" X 3.125" X 4".  Cell Volume 25 Cubic Inches):



and here is the blow-molded RM propagation tray I prefer (Cell Dimensions - 2.25" X 2.25" X 4".  Cell Volume - 11 Cubic Inches):

Thanks for setting me straight.

Julio Budreaux wrote:

Kai Walker wrote:I can get cheap used plain food grade 5-gal buckets with lids at walmart bakery for 2 for $1.00 !
I may make more of those pots. But it takes 2 hours to make one

Now THAT is a deal! Whenever I've made them it's only taken me about 5 - 10 min per bucket. What system are you using?

bob day wrote: I started thinking about  making a contraption that could easily turn a regular throw away  garden pot into something with all those outward facing cone shaped holes [...]
Anyway, I saw this post  and wondered if anyone else has thought about this  or constructed some apparatus (failures just as valuable as successes) before I get busy and actually start working on the project.

No, I've not ever thought of something like that. I'd be interested in seeing a prototype if you were to put one together!

Scott Foster wrote:I'm a fan of Akiva at twisted tree farms.  I've had my eye on this method for a while but haven't done it yet.

I had a bed almost identical to those shown in the video at my last house and attempted to grow spinach and arugula in them. They were INCREDIBLY hard to keep watered (too much exposed surface area in my hot climate) and the spinach died from lack of water, while the arugula bolted early and became far too peppery for my tastes. Perhaps something like zucchini or strawberries would do better, but keeping them watered would continue to be a struggle for me here in Central Arkansas. Besides, I gave up on zucchini (vine borers are really bad around here and I don't use pesticides, so it's a losing battle for me) and my strawberries seem to be enjoying their hugelbed just fine.

We are using a corded drill and a very DULL 2 1/2" hole saw.

Time required is all that measuring to get them all centered properly.
We made a small template of sorts and that did help a bit.
That was for the air pot pruning buckets we made.

Go to any walmart that has a bakery inside.

Ask about their 5 gal frosting buckets with lids. They ARE food grade obviously!

Don't mention $$ just ask what do they do with them when they are empty.

You just might get them for free!

Buckets are not thick plastic though, like you would get for pickle buckets.

I tried landscape cloth lining the inside with limited success. I made 2 more and used plastic window screen. Not sure how long it will last. Copper screening might be best though, Costly too.

Theory: most roots die when exposed to sunlight (at least any end part that is exposed).
You either will get air pruning or sun pruning or both that way.
And more air too.

The place I get my coffee grounds always throws the filters in the bags too. I think I'll try making one of the buckets and covering the holes with coffee filters.  Hopefully it will work the way the root pruning bags work and have the same effect,  while holding the soil in.

First attempt.  Holes right size? Right number? Right mix? Who knows? I used about a third each of potting soil,  vermiculite,  peat moss. 1 inch holes.  Covered the holes with used coffee filters.  Pro tip: drill the holes slowly.  One picture showed two holes. A nice neat one,  and a ragged looking one only a mother could love.  Guess which one was drilled fat and which was slow?

I highly recommend stepped drill bits.  I use them for making 100s of nice 1" holes quickly in the sides of 5 gallon buckets for my fig collection.

I really want to try a commercial root pruning system of some sort, but everywhere I look it seems you have to buy these in huge lots.  I would like to try gradually stepping up in size the way I have seen recommended, from propagation cells to 1 gal pots, to 3 gal pots, and so on, but I'm not willing to buy a large number of these at one time just to test them out.  Not to mention, most of the sites selling these systems are not as user friendly as I would like.  It's kind of disappointing.

An additional note.   I did buy a pretty large quantity of root pouches.  I haven't had plants in them long enough yet to test the root pruning aspect, but I can tell you, these are nearly impossible to keep from drying out.  If you put them into the ground, they are fine and have no issues, but I assume they won't root prune then, or at least not as well.  If they are just sitting out, the need to be watered thoroughly pretty much every day.  The fabric allows the soil to dry out amazingly fast, so that may be something to keep in mind if constant watering isn't possible.

I have updated the information towards the top of the thread!

Trace Oswald wrote:I really want to try a commercial root pruning system of some sort, but everywhere I look it seems you have to buy these in huge lots.  I would like to try gradually stepping up in size the way I have seen recommended, from propagation cells to 1 gal pots, to 3 gal pots, and so on, but I'm not willing to buy a large number of these at one time just to test them out.  Not to mention, most of the sites selling these systems are not as user friendly as I would like.  It's kind of disappointing.

You can order onsie-twosie from Root Maker, and Amazon will sell AirPot-style pots singularly, as well. However, these are both expensive options for a single pot when shipping is included.

Update:

So far, I've only gotten a handful of sprouts (four total--yeah, yikes). Towards the end of July, I dug up the seeds in the Air-Pots and they simply didn't crack. The soil seemed moist enough, but the seeds themselves apparently weren't viable. This was the same for the 1-gallon tallboy tree pots. It was a huge disappointment.

Three sprouts germinated in the RootMaker II pots, and one in an Air Pot. I still have the remaining RMII's filled and planted, but I will likely dig them up towards the end of August to recycle the soil into my garden.

This makes two years in a row that I have had very-to-extremely low germination rates, though I am still ahead in seed cost vs purchasing seedlings (where the KSU seedlings cost $25 each). However, once the cost of the planters are included, I'm in the red. I do not intend on purchasing Pawpaw seeds from Baker Creek next season.

Next year, I will scale back the experiment; purchase all-new, fresh seeds direct from KSU; and add the RediRoot pots to the experiment.  I will also attempt to transplant 2-3 wild suckers into each brand of air pruning containers to include in the grow-parison.

For the time being, I moved all of the seedlings, and the two wild suckers I pulled from a patch, into RMII 1-gal pots and they seem to be doing well. The seedlings which sprouted in the RMII are noticeably healthier and more vigorous than the one that began in the Air Pot, though they are also about a month older. A few of my 3-year-old trees in 5-gallon containers with holes drilled seem to be suffering from a calcium deficiency, so they will be going in the ground next spring--but it is important to note that the 5-gal containers are not set up as "root pruning" containers per say, they simply have a few holes drilled along the circumference halfway down and again at the bottom to allow a bit of air exchange for the root zone.

Outside of the pawpaws, I have used those 3-gallon fabric containers Jeni Lee sent me (thanks, Jeni!) for my White Mulberry trees and they are THRIVING. I've found them easy to maintain with watering and, like I said, the trees seem to be enjoying their new homes! I can't comment on the root-pruning aspect of the RediRoot fabric containers just yet, but I expect them to work at least as well as any other fabric container, though they do seem to be built more sturdily than those I've tried in the past.

And, for what it is worth, I've also found another brand of air-pruning containers from China that are INCREDIBLY cheap, and have done well for my smaller plants over the summer. Unfortunately, the largest size is 6 inches, so about 1 liter in volume. The brand name is BangQiao if anyone is interested and they can be found on Amazon. I will be using these for my vegetable starts next year, as I have been very impressed so far.

Thanks for all of your interest in following this thread--I will start a new one once planting gets under way next spring!

Timothy Markus wrote:Thanks for setting me straight.

Timothy,

The BangQiao air-pruning containers I mentioned in my post above have replaced the RootMaker II blow-molded propagation cells/tray as my favored seed-starting containers. I thought you'd enjoy learning that since we had the discussion earlier in the thread. If you're interested, I'd recommend checking them out! They're very reasonably priced, as well.

Julio Budreaux wrote:

Timothy Markus wrote:Thanks for setting me straight.

Timothy,

The BangQiao air-pruning containers I mentioned in my post above have replaced the RootMaker II blow-molded propagation cells/tray as my favored seed-starting containers. I thought you'd enjoy learning that since we had the discussion earlier in the thread. If you're interested, I'd recommend checking them out! They're very reasonably priced, as well.

Hi Julio!  I know this post is old,  it came upon it as I’m looking for a better propagation system and was interested in fabric pots for final growing this summer. Just the usual small garden items for a family. I live in Colorado at 7500’ and don’t have a greenhouse. My biggest problem is not being able to get an early start, we often get big snow storms in May.  I’m clear after Memorial Day but the next major hurdle I’ve discovered is the ground seems to be too cold for significant growth. Though we have crazy hot days with punishing sunshine in June, I don’t see significant growth until July.

I’ve always planted in the ground but last spring I used a 10 gallon fabric pot for a plant that seemed to grow much better. I even measured the temp on the top of the fabric pot and it was higher than the garden in the ground— I believe because the surrounding earth pulls the heat away from my normal garden.

So I’m thinking of planting everything I want (tomatoes, cucumbers, herbs...) in fabric pots that I can put outside as early as May (and bring them in when it snows or has a cold snap), and with the additional warmth from the earth not sucking the heat away I hope to finally have a productive garden this summer.

The fabric pots I’ve used are these: VIVOSUN 5-Pack 25 Gallon Plant Grow Bags, Premium Series 300G Thichkened Non-Woven Aeration Fabric Pots w/Handles - Reinforced Weight Capacity & Extremely Durable (Black) https://smile.amazon.com/dp/B00VWU30EK/ref=cm_sw_r_cp_api_glt_fabc_VVW0K1HFDRK160682ASA?_encoding=UTF8&psc=1
Have you tried this type before?  Do they perform well for air pruning purposes which benefits contain plants?

Also, for propagation trays, why specifically did you NOT like the RM injected cells?  Why were the smaller  RM trays better for you?  Thank you

Seth Marshall wrote:
Hi Julio!  I know this post is old,  it came upon it as I’m looking for a better propagation system and was interested in fabric pots for final growing this summer. Just the usual small garden items for a family. I live in Colorado at 7500’ and don’t have a greenhouse. My biggest problem is not being able to get an early start, we often get big snow storms in May.  I’m clear after Memorial Day but the next major hurdle I’ve discovered is the ground seems to be too cold for significant growth. Though we have crazy hot days with punishing sunshine in June, I don’t see significant growth until July.

I’ve always planted in the ground but last spring I used a 10 gallon fabric pot for a plant that seemed to grow much better. I even measured the temp on the top of the fabric pot and it was higher than the garden in the ground— I believe because the surrounding earth pulls the heat away from my normal garden.

So I’m thinking of planting everything I want (tomatoes, cucumbers, herbs...) in fabric pots that I can put outside as early as May (and bring them in when it snows or has a cold snap), and with the additional warmth from the earth not sucking the heat away I hope to finally have a productive garden this summer.

The fabric pots I’ve used are these: VIVOSUN 5-Pack 25 Gallon Plant Grow Bags, Premium Series 300G Thichkened Non-Woven Aeration Fabric Pots w/Handles - Reinforced Weight Capacity & Extremely Durable (Black) https://smile.amazon.com/dp/B00VWU30EK/ref=cm_sw_r_cp_api_glt_fabc_VVW0K1HFDRK160682ASA?_encoding=UTF8&psc=1
Have you tried this type before?  Do they perform well for air pruning purposes which benefits contain plants?

Also, for propagation trays, why specifically did you NOT like the RM injected cells?  Why were the smaller  RM trays better for you?  Thank you

Hi, Seth!

What you're saying about in-ground vs above-ground growing, especially in your climate, makes a lot of sense. A ground temperature above 65* in your garden is important for root growth; it sounds like this does not occur in your particular micro-climate until much later in the year. Cases like this are one of the textbook examples of where container or raised-bed gardening makes sense. Depending on your site, you may find building permanent or semi-permanent raised beds to be more appropriate than container gardening, or vice-versa.

If you are intent on going the container route, I have used and continue to use the Vivosun grow bags; they work well. I have also used other brands--such as Gardzen on Amazon--that work equally well and cost less. I do not believe the mechanism is the same between grow bags and airpot-type containers (root trapping vs air pruning) but the end effect remains the same: a ridiculous rootball and the ability to keep a plant potted for longer before the need to up-pot. One thing I've learned, though, is to mix the potting medium for more moisture retention than you would use in something like a plastic or terracotta pot; fabric pots and airpot-style containers dry out much more quickly than traditional containers. If your mix normally calls for ~32 fl oz of vermiculite per 6 gallons of medium, consider doubling it; if it calls for 1 part perlite to 4 parts peat moss, consider a 1:6 ratio instead... Things like that.

The RootMaker propagation cells were difficult to pack efficiently, dried out too quickly, and I didn't see any real difference between plants grown in them vs. more traditional propagation trays. The RootMaker propagation trays had more impressive root development than the injection-molded cells but were far less sturdy and it was pretty inconvenient to get the seedlings out for transplanting. I've found the BangQiao pots to be my preferred containers for starting seeds. If they made 5- or 10-gallon containers in the same style, I wouldn't use anything else. They're amazing.

Thanks for your reply!