Here are some tidbits from the podcast, and a question of mine contained in there:
seedlings spend 1-2 years in a 1 gallon root maker pot. Do root work after every stage.
Then they go in a 10" rootmaker bag in the ground. Fill bag about 1/2 way. Put a barrier (what do people think this barrier is? Tile? wood, etc? and over the whole circumference of the bag, or leaving some space around the sides?), a little layer of soil on that, manually spread roots on that. Use soil or a staples to position them. [then, I assume they fill the bag the rest of the remaining 1/3 up with soil, but they got sidetracked and didn’t finish this thought]
Soil for inside bag: nursery mix of 40% pumice, 40% composted bark mulch, 20% composted steer manure
I’m about to try these bags on pomegranante, pine, quince, elm, crape myrtle and brazillian rain tree–a couple of each.
I wonder if the 40% pumice in their mix is to give the pines some extra oxygen. This year my deciduous grew like weeds in the ground in the native soil, which is far denser. Maybe I’ll keep the soil in the bag more dense for the deciduous? hmm…
I have grown the following in Rootmaker pots: Mikawa black pine, red pine, crabapple, Trident maple and Japanese maple. Began with about a dozen of each as 1 year old seedlings 9-10 years ago.
Initially planted seedlings in 3" Rootmaker pots and stored them in my unheated garage packed in mulch in large tubs through winter, then repotted into larger Rootmaker pots about every other year. Most are now in Rootmaker Injection molded 3 gallon or 5 gallon pots. Roots are amazing. Thinking of shifting aobut 1/2 to bonsai training pots towards the end of winter, keep the other 1/2 in larger Rootmaker pots for another year.
All trees planted in the Rootmaker pots use a premium blend of Sifted Akadama, pumice and red lava rock (don’t know the proportions but they look equal), plus small amount of river sand; no organic material in my mix. Particle size was small (shohin size) the first two years, larger now.
Also planted two of the crabapples inground in the 3rd year (protected by burlap in winter). They are now 7-8 feet tall with 3" trunks. May simply maintain them as full size trees. Planted two of the maples in ground 3-4 years ago; placed clay tile below each rootball to spread roots; have yet to pull them from the ground. Both were 7-8 feet tall and extremely healthy this summer, each with a twin trunk. Did my 1st trunk chops this Fall (ouch); they are now about 8" tall. Curious to see how they push growth this Spring. Will allow them to grow freely inground for another 1-2 years (doing some trimming along the way), then transplant both into training pots early Spring of 2020.
Began this journey to have something fun to do over winter since my mature bonsai trees are stored in a temperature-controlled greenhouse out of state (until I pick them up each April).
Have not used the Rootmaker bags so I cannot comment…but as noted, I have had great success with Rootmaker products to date. You should too.
@gary1218 received an FAQ from Rootmaker and was kind enough to share it with me. Here is one snippet
As a general rule, good field soil is the best medium for filling the Root Control Bag-In Ground. Return all soil removed by the auger to the bag. With the same texture inside and out, water moves both into and out of the Bag with ease. Likewise, the same soil inside and out prevents any abrupt textural differences that restrict rapid horizontal root development. A few customers do amend their soil backfill. Because water moves readily through the fabric, drainage can be a problem. Make sure your amended soil is not lighter than the surrounding field soil, where water could be trapped, or pooled, in the Bag. Do not backfill the Bag with a light mix and bury it in a field of heavy clay. The water will pool in the Bag and plant growth will be negatively effected.
Personally, I amended the soil in the spot where I was going to plant with more decomposed bark and pumice. The soil was okay, but did border on a little too much clay. In the bags, I went a little heavier on the pumice, somewhere around 50/50 mixture of potting soil/pumice.
I don’t know if this is the right answer, or the best answer, but it the direction I went.
Thanks much! What about the smaller plastic pots (i.e. the ones you aren’t growing in the ground yet) – any ideas? Field soil, start 'em on pumice, or a mix?
I don’t know if this is helpful or not, but I used the felt-type root-control bags for years in my nursery for field-growing bonsai stock. There were advantages and disadvantages with their use. The advantages were that: 1. The fabric did indeed self-prune the roots as they grew through the fabric causing roots to branch and divide repeatedly in the bag. 2. As you cut away the fabric, you would notice that the roots had formed knots on the inside of the bag. they ranged in size from a small pea to marble size. These nodules were stored food reserves and gave the trees a huge head start on recovery when dug up and planted into a training pot, wooden grow box or bonsai container. 3. You could dig up trees virtually year-round. The disadvantages were: 1. The bags were a real pain to remove from the root mass. You literally had to use scissors to cut each and every root away from the fabric. 2. Even after following the directions for field-planting material in the bags to the “fill-line”, which left about 3 inches of fabric above the surrounding soil, the fabric would fall over in rain and snow and quite often, a surface root would “escape” over the top of the bag and would greatly enlarge due to growing unrestrained and ruin the nebari. But I did have a lot of success with them, despite the problems.
In my personal experience, which isn’t very extensive, I’ve had better luck starting seeds in potting soil than anything else. For example, I have some kumquat seedlings in akadama and some in potting soil right now, and the ones in potting soil are much larger (both are in similar plastic training pots). My potting mix is a cactus mix, which is supposedly a little more free draining than regular potting soil.
In the podcast Telperion Farms did with Ryan they mentioned that their substrate for the root control bag was 40% pumice, 40% composted bark mulch, 20% composted steer manure.
I purchased 500 3 gallon rootmaker pots in 1993 after experimenting with them in the late 1980,s. No question, all trees grown in them were superior to any other pots. Using a soil with extended life I often leave trees for up to 8 years in these pots with great results. Perhaps most amazing thing about these containers is that nearly all 500 of them have been continuously used for over 25 years and they are still in great shape.
I’ve also had the 1 gallons in use for the same length of time, equally successful, but only about half remain as they have become brittle and cracking up. No complaints though, I got years more out of them than I anticipated.
It has been a few years since I was field-growing trees for bonsai, but I believe they were in the ground about three years before I started harvesting them. Not all the trees were escaping the grow-bags, maybe about 30-40%. Even though I was planting them at the line marked on the bags, the sides of the bags do not stand erect. They fall over. And it was not uncommon to have a root escape over the top. And when that happened, the root would grow unchecked and ruin the nebari - which was the whole reason I was using the bags in the first place. I had a few escape through the sewn seam at the bottom as well. But that was only maybe 1 out of 30. In short, I discontinued using the bags after about 10 years. I was working just as hard if not harder trying to free the trees from the bags as I was just planting them in the ground on a large piece of tile and digging them up and conducting root pruning every couple of years. The tile help to ensure that I had a shallow root system immediately under the trunk, spreading out about 6-10 inches all around (depending on the size of the tile). I also found that the trees grown in bags had a smaller trunk caliper than those I grew in the ground. I did get (on those trees that did not “escape” the bag) better nebari than what I typically got in the ground, including pines, but ultimately ( at least for me) I determined that the bags were not worth the trouble.