Oak trees produce acorns, which house the seed of the tree. Acorns do not fly in the wind to reseed themselves because of their weight. Collecting and planting the acorns indoors allows you to produce additional oak trees for your yard. Oak seeds must be collected immediately after they have fallen or pulled directly off the tree to prevent drying out. Store the acorns over winter and plant them in April for best results.
Gather acorns from the oak tree when they start falling in the autumn season. Choose acorns that are not dried out or cracked. Eliminate dried acorns with a float test by placing all acorns in water and discarding those that float.
Place acorns in a plastic bag filled with leaves and peat that is slightly damp. Set in a refrigerator with a temperature of 32-35 degrees F to winter over. The acorns will be planted in April.
Sort through acorns after their winter dormancy to eliminate any that have dried out. Prepare 8-ounce Styrofoam cups by poking three to four drainage holes around the bottom edge of the cups. Create an even mixture of potting soil and milled sphagnum moss. Fill each cup to the top and tap to settle the soil leaving a one inch space at the top.
Set one acorn horizontally in each cup just under the surface of the soil. Water each cup until the water flows out of the bottom drainage holes.
Set the planted acorns on a windowsill. Check the soil moisture daily to prevent the cups from drying out as this will also dry out the acorn seed.
Plant growth begins between 1-3 weeks with the first leaves showing shortly after. Begin to harden the plants in late spring by gradually exposing them to the outdoor elements.
Transplant the trees to a 16-ounce cup or container after 2-3 weeks of outdoor hardening. Make sure the container has lower drainage holes. At this time the roots should have began to curl around the bottom of the 8-ounce cup. Use the same soil mixture as the previous step.
Find a safe location to keep the seedlings outdoors where wind, sun and rain is not damaging and the seedlings are protected from rodents that like to chew on young plants. Make sure the soil stays damp to prevent the seedlings from drying out.
Transplant the trees to a larger 32-ounce container once they produce a second flush of leaves. The tap root should be curling around the bottom of the 16-ounce cup at this time. This will occur around mid to late summer.
Plant the new seedling tree in the ground in late fall or winter them over in the pot and plant in spring. Move the trees to a protected porch or cool basement location with temperatures that range from 5 to 45 degrees F to over winter.