Most edible nut trees are propagated by grafting to ensure high quality and provide quick results. However, nature reproduces walnuts, pecans, cashews and other nuts trees with seeds. Growing nut trees from seeds in your own garden or orchard can be a fun experiment and is a lot cheaper than buying nut tree seedlings. Store-bought seedlings, however, will start producing crops in just a few years, while nut trees started from seed may take ten years or more to mature.
Collect nut tree seeds. You need the entire fruit of the nut tree---shell, hull and all---not just the edible nut portion sold in grocery stores. Collect nut tree seeds from trees in the wild or from other people's gardens.
Plant the nuts directly in the ground in the fall. The germination rate will be much lower, due to the variables of weather and animals who might eat the seed, but this method most closely resembles what would occur in nature and requires a lot less work from you. Dig a hole in a suitable location--most nut trees like full sun and well-drained soil--and bury the nut seed under 4 to 6 inches of soil. Plant nut tree seeds outside at whatever time of year the trees naturally drop their seeds, usually late fall.
Bring the seeds inside and place them in a plastic bag with moist peat moss for a more controlled germination. Close the bag loosely and store it in the refrigerator for about three months. This will provide the period of cold stratification that most nut seeds require for germination.
Check the bag regularly over the winter, misting the peat moss if necessary and watching for mold. If mold does form, remove the moldy peat moss and transfer the seed to fresh peat moss, but it may be a lost cause at that point.
Remove the nut seed from the refrigerator and plant outside as soon as the ground is workable. If the nut tree is hardy for your area, a few late spring frosts or even some snow should not hurt the seed. Plant the seed about 4 inches deep and keep the area well-watered throughout the first growing season.
Pull weeds around the nut tree seedling, and apply a few inches of mulch around the base of the tree once the plant is established. Keep the mulch a few inches from the sapling so that the bark can breath.