Environment Planet Earth Plant an Acorn and Grow an Oak Tree Easy-to-follow instructions show how to collect, prepare, and plant an acorn. By Steve Nix Steve Nix Writer University of Georgia Steve Nix is a member of the Society of American Foresters and a former forest resources analyst for the state of Alabama. Learn about our editorial process Updated August 3, 2022 Share Twitter Pinterest Email Treehugger / Hilary Allison Planet Earth Outdoors Weather Conservation In This Article Expand Collecting Acorns Storing Acorns White vs. Red Oak Germinating and Potting Transplanting Beginning as early as late August and continuing through December, various species of oak acorns are maturing and ripening for collection. Ripening dates vary from year to year and from state to state by as much as three to four weeks, making it difficult to use actual dates to determine maturity. The best time to collect acorns, either off the tree or from the ground, is when they begin falling. Prime picking is late September through the first week in November, depending on oak tree species and location within the United States. This tree seed called an acorn is perfect when plump and the cap removes easily. Collecting Acorns Treehugger / Dan Amos The height of the acorn crop above the ground and the forest understory below can make it very difficult for the casual collector to gather large numbers of acorns in a forest setting. Lawns or paved areas will better visibility help in collecting acorns if trees are found and prepared before site conditions degrade the nut. Locate open-grown trees that are heavily loaded with acorns and are in or adjacent to parking lots such as at churches or schools. Trees selected in this way also make identifying the acorn's species easier. Always identify the tree and place tags or mark the bags so you will know what species you have collected. Avoid acorns that still have caps attached. Check the acorns' viability by putting them in a bowl of water. Any that float will not sprout. Keep the ones that sink to the bottom. You can plant them right away or store until spring, but what you choose to do depends on the species. Immediate planting should be limited to the white oak species group including white, bur, chestnut, and swamp oak. Red oak species group acorns must be planted in the second season, meaning the following spring. These acorns need about 1,000 hours of cold, or around 42 days. This is called stratification. Planting them in late April of the following season gives you the best success, but they can be planted later. Storing Acorns Treehugger / Dan Amos To store acorns for future planting, put them in a polyethylene plastic bag—a wall thickness of four to ten millimeters is best—with damp peat mix or sawdust. These bags are ideal for storing acorns since they are permeable to carbon dioxide and oxygen but impermeable to moisture. The two most critical components of caring for acorns that are to be planted are: Not allowing the acorns to dry out over an extended period of timeNot allowing the acorns to heat up Acorns will lose their ability to germinate very quickly if allowed to dry out. Close the bag loosely and store in the refrigerator at 40 degrees (white oaks can still sprout at between 36 and 39 degrees). Check acorns throughout the winter and keep just barely damp. Do not freeze acorns. White vs. Red Oak Treehugger / Dan Amos White oak acorns mature in one season—the season of collection. White oak acorns do not exhibit seed dormancy and will start to germinate very soon after maturing and falling to the ground. You can plant these acorns immediately or refrigerate for later planting. Red oak acorns mature in two seasons. The red oak group has to have some seed dormancy and generally does not germinate until the following spring and with some stratification (a cooling period). If stored properly and kept damp, these red oak acorns can be held in cold storage for planting in late April through early summer. Germinating and Potting Treehugger / Dan Amos After determining the proper time to plant, you should select the best-looking acorns (plump and rot-free) and place two in a one-gallon pot with some loose potting soil. Plant multiple pots if you can, each with two acorns. The taproot will grow quickly to the bottom of containers. When both have sprouted and grown for a week or so, cut off the smaller of the two seedlings. Don't pull out the acorn, as its roots will have entwined with the other. Containers should have holes in the bottom to allow for drainage. Place acorns on their sides at a depth of one-half to the width size of the acorn. Keep the soil moist but aerated. Keep the pots from freezing. Transplanting Treehugger / Dan Amos Don't allow an oak seedling’s tap root to grow out of the container bottom and into the soil below. This will break the taproot. If possible, seedlings should be transplanted as soon as the first leaves open and become firm, but before extensive root development occurs. The planting hole should be twice as wide and deep as the pot and root ball. Add some organic material like compost to enrich the soil. Carefully remove the root ball. Gently set the root ball in the hole with the root crown at the level of the soil surface. Fill the hole with soil, firmly tamp, and soak. Mulch the area around the seedling, but maintain a two-inch boundary around the seedling's base to prevent contact with the mulch. Add a mesh guard to protect the tree from predators and accidental crushing. It will likely need the guard for several years. Correction—September 6, 2022: A previous version of this article contained incorrect information about how to perform a float test to determine acorn viability. View Article Sources “How do I germinate acorns?” Iowa State University, Extension and Outreach.