Growing an oak tree from seed is a slow but satisfying method of propagation. Oak trees can be difficult to grow from cuttings. Preserving a favorite tree or family heirloom can be accomplished by collecting and germinating acorns. The process is not labor intensive, but it does take some time. A few tools and techniques will allow anyone to grow oak trees from acorns.
Harvest the acorns in early fall. Make sure they are still slightly green, with just the beginnings of brown coloration forming. Examine them closely for insects and moldy or rotten areas. Place the selected acorns in a bucket of water. Discard those that float, as these typically will not germinate.
Place the non-floating acorns in a heavy plastic, resealable bag filled with lightly dampened peat moss or sawdust. Put the bag in the refrigerator for a few months, checking periodically for mold or rot and removing questionable acorns. Plant the seeds when the roots begin to protrude from their split shells, usually in December or January.
Place the acorns in large seed flats and leave outside for the winter as an alternative to putting them in a refrigerator. Place chicken wire and/or a layer of sawdust mulch over the seed flats to help protect and insulate them.
Plant the acorns 2 to 4 inches deep in small pots of loamy, well-drained soil. Water regularly until the soil is thoroughly wet. Allow the top inch of the soil to dry out before watering again.
Plant the oak seedling in the ground in rich, well-drained soil when it reaches 1 to 2 feet tall. Water once a week, more often if the soil is very well-drained or sandy.
Place a layer of bark mulch around the tree to control weeds and retain moisture. Keep the mulch from directly touching the trunk of the tree as mulch can hold water and cause disease or rot.
Things You Will Need
- Plastic bucket
- Plastic resealable bag
- Peat moss or sawdust
- Chicken wire
- Small pots
- Bark mulch
- Acorns need a process called 'stratification' to germinate properly. Stratification is exposing the seeds to a prolonged cold period. Many tree seeds of plants native to colder areas need this treatment.
- Leaving seeds outside to stratify has some drawbacks. Seeds cannot be readily inspected, and squirrels and other wildlife may make off with the acorns. An episode of severe cold could damage the seeds.
- Regular water is crucial for young trees. A period of drought can stunt the seedling or even kill it. Growth of the oak seedling may be slow the first few years.
- Very small pots may require watering at least once a day.
- Fertilizer usually is not necessary for oak trees.
- Seasonal growth varies between oak species. If the seedling is 8 to 10 inches tall by the end of summer, it is important to repot it. Pot into a container that is at least 1/3 larger than the previous pot. In cold areas, small pots may not provide enough protection for the roots. Bury them up to their rims in sawdust or mulch, and remove them in the spring.