Oak trees grow throughout the United States and there are many different varieties. Some grow in dry upland areas and some prefer the moist lowlands. Mature oak trees begin to produce seeds, commonly called acorns, sometime after 20 years of age. It can be a challenge to sprout oak seeds, but it can be done.
Know the Type of Oak Where the Seed Originated
The seed from different types of oak trees needs certain conditions to sprout. Seed from the red oak family—which includes the Shumard, southern red and northern red oak, blackjack oak, willow and water oak—must have a chilling period, or stratification period, to sprout and may remain on the tree for several years before falling off. Members of the white oak family, which includes post oak, live oak, bur oak and Chinkapin oak, usually sprout the following spring without a chilling period. Do not pull acorns off the tree. Only collect seeds that have recently fallen from the tree.
Finding Viable Seed
Look for acorns on the ground under the canopy of an oak tree in late fall after the acorns have been falling off the tree for a few months. The first acorns to fall in late summer and early fall are not always the best seed. Look for seed that has no wormholes or rodent damage and no obvious mold or fungal problems. Avoid old seeds that are obviously left over from the previous season.
Storing the Seed
Store the seed in a plastic bag at 35 degrees Fahrenheit. The bag should not have ventilation. It is important for the seeds to be stored in the cool moisture the bag provides. Every few days, open the bag to look for rotting or mildewed seeds. Remove any of these from the bag and discard. Acorns of the red oak family can be stored in this manner for as long as three years. Seeds from the white oak family, however, will begin to sprout after a few months and need to be planted at that time.
Floating the Seed
After two or three days of cool storage in the plastic bag, take the seed and place in a bucket or other container filled with cool water. A seed that floats is defective and should be discarded; it may be hollow, rotten or worm-infested. Take the seed that sinks, which is the good seed, and place it back into the plastic bag. Return the bag to storage at 35 degrees Fahrenheit.
Seed from trees of the red oak family need a cold period, or stratification, to sprout. This can be done by planting the seeds 1 inch deep in damp sand and placing in a temperature-controlled environment where the temperature remains between 32 and 41 degrees Fahrenheit for 90 days before planting. Germination will begin to occur on some seeds during the 90-day period. Those seeds should be planted right away. Be careful not to damage the new roots of the plants when planting. Red oak acorn seed can also be planted outside to let natural stratification occur; however, the seeds are susceptible to rodent damage when left unprotected.
Planting the Seed
Acorn seed is planted in any position because the roots and new sprouts come out of the same place on the seed. Although acorn sizes are different, the seed should be covered with 1 to 3 inches of soil to conserve moisture around the developing seed. If planting in a container, plant in a square pot to prevent the developing roots from growing around the root base. Also, the container should be at least 8 inches deep to allow roots room to grow downward. Add drainage holes to the container so the tree does not sit in waterlogged soil.