Although potting evergreen seedlings is generally not as good or as successful as planting directly in the ground, potting can work well if done right. You need to pay close attention to watering, direct sunlight, fertilizer, soil mixes, and other factors.
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Evergreen Seedling Planting Videos
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Evergreen Seedling Temporary Storage Instructions
Evergreen Windbreaks and Privacy Screens
Evergreen Tree Winterburn
How Trees Sequester Carbon
Evergreen Seedling Potting Instructions
If you choose to pot your evergreen seedlings, keep in mind that normal rainfall will not be adequate except in large downpours. The seedlings will need the equivalent of an inch of rain per week. However, it is best not to give them that much all at once. Instead, pour half an inch of water across the top of each pot twice a week, to spread out the watering and reduce moisture fluctuations.
Pots generally can’t capture or hold moisture for as long as the actual ground, but sometimes they hold too much. The pots must have numerous finger-sized holes in the bottom to allow for proper drainage. If the roots are constantly wet, they will be attacked by numerous species of fungus and start to rot and kill the tree. Cover large holes with a rag or sponge before filling to keep dirt from falling through the drain holes while still allowing proper drainage. Get to know how heavy each pot weighs after a good watering. If it still feels heavy days later, consider skipping watering for a few more days. Individual results will vary based on the type of pot used, the species of tree, whether it is actively growing or not, and the temperature.
After watering, the second most important factor is protecting the potting soil from wild temperature fluctuations. The pot should be white or very light in color, or must be protected from direct sunlight if the pot is black. Lightly colored mulch or wood chips on top of the pot dirt will also help to reflect sunlight and keep the pot cooler during mid-day. Direct sunlight hitting the pot in summer [or on the south side in the winter] will result in damage to the roots or withdrawal of the roots from the side facing the sun [see photos below]. Try to emulate the cooler and more gentle temperature fluctuations of the ground itself, as this will result in a much healthier tree.
The photos on the left [above and below] show vigorous root growth on the shady side of a black pot, while the photos on the right [above and below] show poor root growth due to overheating from direct sunlight from the West. The white spots are vermiculite, an amendment added to the soil at transplanting time to increase airflow within the soil.
The “root plugs” shown above are of evergreen plug transplants, which are “container grown” in trays. Evergreen plug transplants can be planted very quickly and easily with our specially sized auger. The trays in which they are grown have channels which prevent the evergreens from becoming root-bound. See the second planting video from top on this page
The advice given thus far is even more important during the late fall and winter months. Nearly all evergreen trees need winter weather for normal growth, and should therefore be set outside. Heeding the “no sun on the pot” rule, set them on the north side of your house or garage and allow them to get snowed in. Avoid putting them directly under a drip-edge or other location where an icefall could cause damage.
For evergreen seedlings and evergreen plug seedlings, the pots should be at least 6-10 inches deep, and for evergreen transplants and evergreen plug transplants, at least 10-16 inches deep. Although the roots can be trimmed, it is better for the pot to be a little too big than a little too small. For short term potting [such as a wedding or special occasion], you can use smaller pots. If you intend to grow them in pots for a year or more, consider doubling the pot size you have in mind. Larger pots reduce the changes of a blow-over due to strong winds.
Lastly, please understand that since potting introduces additional variables and risks as opposed to planting in the ground, we cannot guarantee your trees if you pot them.