The process starts with some advanced planning. To germinate pecans effectively, the seed needs to be stratified (stored under cold moist conditions). I like to stratify my seed for at least 120 days to improve uniformity of germination. Details of the stratification process were posted previously on this blog.
|A germinated pecan seed|
|Tall One pot (4 x 4 x 14 inches) and|
Anderson Band (2.9 x 2.9 x 5.5 in)
When I first starting planting pecans in containers I used the "Tall One" style pot but have since switched to the smaller "Anderson Band" container (photo above). The smaller pot seems to create a denser profusion of lateral roots and makes transplanting in the Fall easier (smaller hole to dig). There are many other styles and sizes of containers designed for growing tree seedlings (see Stueve & Sons, Inc.). I've thought about trying some of these other pots but then I look at the supply of pots I already have stacked in the barn and I always decide to stick with what I've got.
|Bottom view of a Anderson Band container|
I use a totally artificial soil mix for growing pecan trees in pots. The mix I use contains processed pine bark, peat moss, vermiculite, and perlite. Two commercially available soil mixes are Fafard Growing Mix 52 and Scotts Metro-Mix 702. Since these soil mixes have little or no nutrients needed for plant growth, I mix in a slow release fertilizers such as Osmocote 19-6-12 (12-14 months) and "Micromax Micronutrients". For each 2.8 cu. ft. bag of soil mix, I add 3 cups of the Osmocote and 1/2 cup of the micronutrients before mixing thoroughly. Once the pecan trees have germinated in the pot, I drench each pot with a 1 % solution of "Nickel Plus" to prevent the development of nickel deficiency. A lack of nickel in the potting media is the reason so many container grown pecan trees develop symptoms of 'mouse ear' disorder.
One of the disadvantages of using a very porous potting soil is that you will need to water the trees every day. I make sure to completely soak the soil at every watering. During the heat of the summer (temperatures above 94) water the trees in the morning and in mid-day to keep tree roots from over-heating. Heat damage to the roots can be recognized by the appearance of a marginal leaf burn on the foliage.
I've found that placing my potting bench under the partial shade of two large oak trees has also helped me avoid problems with summer heat. When placed in direct sunlight, the black pots used for growing trees will absorb a lot of the sun's heat causing soil temperatures to rise well above the ambient air temperature. With the combination of partial shade and ample water, I am able to keep tree roots healthy in throughout our Kansas summers.
I never try to over-winter the seedlings I grow in containers. Pecan roots will die if exposed to temperatures of less than 19 degrees F. Although preventing cold injury to potted trees is possible, I find it more hassle than its worth. I will transplant all my container-grown trees into the field starting October 1st or as soon a soil conditions allow.