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How do I start an oak tree from an acorn?
How do I start an oak tree from an acorn?
Acorns, as many other kinds of nuts, can be collected from the ground anytime from early fall to early winter. One can sow them directly in outdoor beds at this time, one inch deep in moist, well-aerated soil with an inch or more of leaf litter. But unless they are also surrounded by or covered with wire mesh, it is a very good bet that they will not survive due to animals digging them up for food. Even if the rodents don't get them, typically one in five or ten acorns is internally damaged by otherwise harmless weevil beetle grubs. Therefore, you can increase your success by collecting several and storing them in a refrigerator over the winter to be planted in the spring.
Some kinds of acorns fall off the tree dormant, asleep, and need to either wait many months or experience winter-like conditions before they will germinate. This is typical of the "black oak group" which includes black oak, water oak, red oak, scarlet oak, Shumard oak, pin oak, black jack oak, willow oak, and shingle oak. Acorns of the "white oak group" have little or no dormancy and will germinate soon after falling. These acorns must never dry out. This group includes white oak, post oak, overcup oak, chestnut oak, basket oak, swamp white oak, bur oak, and English oak.
In either case, no matter what kind of acorns you find, the following cold treatment will provide you with nuts ready for planting in spring: in the one case the cold is a necessary pretreatment to stimulate germination, in the other the cold will keep them from growing much until winter is over and squirrels have other food sources. The key here is to store the acorns in a moist medium as cold as possible, but above freezing (32-40F). This is called "stratification," a term coined by English gardeners of previous centuries who treated dormant seeds by laying them outside for the winter in layers, or strata, of sand. To do this, moistened peat, potting mix, or sphagnum moss is ideal, but nearly any moist loose soil, dead leaves, or sawdust will suffice. Remember, it's going in your refrigerator!. Mix the acorns without their caps in a bag or plastic container with the medium and place on the bottom shelf of your refrigerator. Wait until April and plant one inch deep outside in good soil. The young trees germinate in about two to four weeks, and you will be proud to have given the next generation a mighty oak.