Nut trees are one of the easiest types of trees to start from seed. If walnut trees live in your neighborhood, you might have noticed baby trees popping up in your potted plants and flower beds---wherever the squirrels plant them, they often grow. If you scout around the base of an adult nut tree, chances are you'll find baby trees starting to grow on their own. You can dig them up and pot them if you want, or collect nuts before they fall from the tree and start them in nursery pots.
Research the type of tree you want to start from seed because some nuts require a period of cold in order to germinate: this is the case with black walnuts and some other nut trees.
Collect nuts and plant them in the fall. Plant them 1 inch deep in 1-gallon nursery pots filled with standard potting soil to keep them safe from squirrels, mice and other hungry creatures. If you prefer to plant nuts directly into the ground, first mix compost with your soil and plant the nut 1 inch deep.
Water the planting area well and keep it moist throughout the winter. Also make sure your pot(s) get at least partial sunlight every day.
Fertilize your young tree(s) when they are several inches tall with a balanced fertilizer once a month. Continue fertilizing monthly until your tree is at least one foot tall and ready to be planted in the ground. This can take one year or longer.
Transplant your young tree to its permanent location when it is one foot or taller. Dig compost into the planting area first and keep the newly transplanted tree well watered through its first summer in the ground. Apply mulch around the tree and continue fertilizing as before.