When I decided to try starting my own trees from seed, I started doing some research. I wanted to start them under lights during the winter since I get a bit of cabin fever. I found the biggest issue with container grown trees is circling and j-hooking roots. You can prune these by hand at planting time. The downside is that cutting offers an opportunity for pathogens to enter. But you also have to disturb the root system to do that. Both things mean more transition shock when you transplant. In addition to that, the plant wasted lots of energy growing roots that will never help the tree. Root pruning containers solve all these problems. They force early upstream branching making a better root system.
From all the reading I did, it seemed that Dr. Whitcomb was one of the pioneers in this area. He has a lot of papers describing concepts and methods. I think Rootmaker was the pioneer in commercializing this technology. There are now a lot of other root pruning systems out there. I’m sure they each work to different varying degrees, but I couldn’t find any that seemed to take in to account all of the underlying concepts as well as Rootmaker did. I have friends using some other root pruning containers because they are less expensive for them but none of their results yet convinces me to change. If you are buying them retail, Rootmaker seems to command a premium over some of the competition, but I was planning on producing trees at the prosumer level (a couple hundred a year) for my farm. I was able to get a commercial account with Rootmaker which seems to reduce the premium significantly over the retail premium.
I have not used all of Rootmakers containers. I have not used any of the in-ground bags at all. The specific containers I personally like bests are:
-
Mesh flats lined with shelf liner (Shelf Liner) for initial seed propagation.
-
Rootmaker Express Trays with 18 cells as soon as I see a root radicle with large nuts or and top growth with seeds. They are good for 12 to 16 weeks.
-
Rootmaker Rootbuilder II 1 Gal containers for the first growing season.
-
Rootmaker Rootbuilder II 3 gal containers for the second growing season.
I’ve tried the 5" roottrapper bags. They have some good applications like starting cuttings that need to be cut long to get buds both above and below the medium. The size is a bit awkward for most applications. They do make larger above ground bags, but I like the Rootbuilder II containers better.
I’ve only started using the 3 gal containers and only planted a few trees from them so far as experiments. This fall I’ll be planting a good number of second season bench grafted trees (mostly the Nikita’s Gift persimmons tony provided scions for) from 3 Gal pots.
I have tried planting directly from the Rootmaker 18s in the spring. At first I thought that was the way to go because you can plant a lot of trees at a very low expense both money and labor. I’m beginning to come to the conclusion it is worth keeping them in the 1 gal containers for the first season and planting them when dormant in the fall. I’m not sure yet whether it is worth the extra cost and effort to keep trees for a second season.
The one down side to container grown trees is that without the long tap root as insurance against drought, you need to ensure they have sufficient water until they are well established. In my climate there is no problem if I plant from 1 gal or larger when dormant. By the time summer rolls around they are well enough established for all but a total drought. Planting in the spring can be a bit iffy depending on the weather since I can’t provide supplemental water in my application. For back yards or orchards, I don’t see any real down side except the cost and effort.