Within six months of receiving your tree, you should either plant it in the ground or shift it to a larger potting container. The seedling's root system will need room to expand, and without this extra room, the seedling will stop growing.
If you intend to keep your seedling in a container, the following container sizes should apply:
For six additional months, shift (transplant) to a 3-gallon container
For up to a year, shift to a 5-gallon container
Shifting Your Seedling to a Larger Container
To shift your seedling to a larger container, follow these directions:
Step 1: Add soil. Purchase a small bag of bagged garden soil before you start the shifting process. Use your current one-gallon container to determine how much soil you will need to fill the bottom of the larger container by 2 to 3 inches.
Step 2: Remove the root ball from its container. Once your base layer of soil is packed inside the new container, cut the twine and remove the felt Rootcap disc inside your one-gallon container. You will need to have a free hand available to “catch” the root ball when you invert your seedling's potting container.
Know in advance that the root system of your tree is still very sensitive at this point. Any damage to the root ball (i.e. breaking off a big chunk of the root ball’s soil), can actually damage your young tree. This process of “shifting” your tree to a larger container must be done unhurriedly and with full attention on the steps you are taking. Be very careful and do the job right to avoid damaging your tree, and avoid moving it from container to container as much as possible.
Step 3: Position the root ball in its new container. Once you have the root ball in your hand, position it on top of the soil in the larger container. Again, remember to be gentle with its delicate root system.
Step 4: Assess the top of the root ball. It should be about 2 inches below the rim of the new container. If it is not, gently remove the root ball – keeping it intact – and add more soil to the bottom of your larger container. Continue to add soil until you have 2 inches of air space between the root ball and the rim of your larger container.
While holding the root ball and stem in place, gently fill in air space around the root ball with more soil. Pack it down as much as possible, but don’t let the root ball crack apart in the process.
Step 5: Water your seedling to help pack the soil. Once the root ball has been shifted into the larger container, fill the new container with water to the rim and let it drain down through the new soil until the excess drains through the bottom of the container.
Notes Once Your Seedling Has Been Moved to its New Container
Monitor the temperature: Be aware of the nightly temperatures during the winter months while your tree is outside – and the arrival of cold fronts in your area. Always water your tree well one day prior to the arrival of a major cold front, and make a priority of bringing your potted tree indoors during freezing temperatures. Once the tree has been planted into the ground, the soil will act as a protective insulation blanket for the root system and keep it from freezing. Until that time, your tree’s root ball is vulnerable to freeze damage.
Leaving your tree outdoors: When locating your containerized tree outdoors during the winter months, you may want to consider a more protected location, especially from north winds, which can blow over your tree if strong enough. Your tree will be in a winter dormant state until late February, so it won’t be actively growing during the winter. It will still need sunshine and once-weekly watering throughout the colder months.
Pre-spring “molting”: Live oaks are so named because they display green leaves year-round. During late February or March, your tree will start dropping some of its old leaves from the previous growth season – a molting of sorts. This will happen every year and is a natural part of your tree’s growth cycle. As old leaves drop off the tree, bright new green leaves will be added to replace the old leaves. Every leaf on your tree will drop off at some point within a 12-month period and be replaced by new leaves.
Watering and Freezing Temperatures: Keep the Soil Wet
Continue watering your seedling once per week throughout the winter months – filling it with water completely to the rim of the container each time and allowing the excess water to drain through the container bottom.
Whenever the temperature drops down to freezing or below, always give your tree a thorough watering before the cold snap arrives. Wet soil is much better during cold conditions than dry soil – and helps prevent freeze damage to the root system. As long as the tree remains in its container, remember that the root system is vulnerable to freeze damage. So keep the soil wet during freezing conditions to prevent freeze damage.
Indoors / Outdoors
If possible (and especially if the temperatures drop into the mid-20’s or below), bring your potted seedling indoors during freezing temperatures. A garage will be fine as long as the air temperature is warmer than outdoors. And don’t forget to water your tree in advance of the cold snap.
Otherwise, leave your tree outdoors in full sunshine 24/7 throughout the winter, always watering once per week – or more often if the temps dip below freezing.