The Kentucky Nut Growers Association,
http://www.pawpaw.kysu.edu/knga.htm is a good place to start to find info and going to the annual spring meeting to meet others growing nut trees in your area. The Northern Nut Growers Association,
http://www.nutgrowing.org/ is a source for info for North America. I started growing nut seedlings in composted beds in my garden and found that 1 year seedlings with their fibrous root system transplanted better than 2 year old trees which would develop a taproot. Then started growing nut seedlings in plant bands, basically 1 quart milk carton containers with an open bottom, placed in a milk carton crate, to air prune taproot of nut trees. Had good survival especailly after mulching with strawy cow manure, this is the same type of containers that Oikos Tree Crops,http://www.oikostreecrops.com/ to grow all their container plants in.
I have been recently experimenting with growing chestnut seedlings to develop a fibrous root system for better transplanting survival. In the past I bought bare root grafted chestnut trees from a nursery to plant them out and to have them die in pots which were well watered. Another attempt to grow bare root chestnut seedlings I purchased and transplanted into deep pots had fair survival, but I noticed that root regeneration only occured at the the cut end of the taproot and no roots regenerated along the length of the taproot, also the top grew very little. Another attempt at growing chestnut from seed into shallow containers I observed looking at the root system that once the tap root reached the bottom of the container the top stopped growing and the plant stayed small. Another observation planting chestnut seed in open mesh bottom flats, a sheet of paper on the bottom to cover the holes, 2 inches of organic soil mix, after germination the taproot grew through the bottom and was air pruned, some lateral roots were stimulated. Seed planted 1 inch deep and allowed to air prune as they grew out of the bottom of the container stimulated many more lateral roots. So air pruning right after germination as close as possible to the root/stem interface developed the best fibrous root system I found. So last spring in a friends greenhouse using organic soil mix, I took open bottom mesh flats covering the bottom with a sheet of paper, about 1 inch of organic soil mix, placed the chestnut seed spaced about an inch apart and covered with soil. In about two weeks,after sprouting, in April the seedlings were up and ready to transplant. Chestnut can have uneven germination and this selects out for the best seedlings by transplanting only the best seedlings with the most vigorous fibrous lateral root system. We transplanted the seedlings into RootMaker 18 cell paks designed to stimulate air root pruning. Seedlings left in the containers all summer were about 12 to 18 inches tall, but best of all the root developed a fibrous root sytem. Transplants that were moved up into 1 gallon pots were taller and had a larger fibrous root system. This spring I look forward to experimenting with seed I have collected from grafted trees of chestnut, heartnut, hazelnut, hardy English walnut, and seed from Siberian peashrub, honey locust, black walnut and hickory. The website
http://rootmaker.com/ has the RootMaker containers I have experimented with and there is a video and slideshow at the link that describes the commercial nursery system that Dr. Carl Whitcomb developed.
