Harvest ripe crabapples. Cut them open in half and remove the seeds from their core.
Prepare a seedbed under full sun in the fall. Remove all grass and other vegetation from the area. Break up the soil and amend the site with organic matter, such as compost, and rake the bed to a smooth surface.
Make 1/2-inch-deep furrows and sow your crabapple seeds. Cover them with topsoil. Don't water the seeds at this time, as they're not in the ground to germinate. They need several months in the cold before they'll sprout in spring. This chilling process is called stratification.
Begin to irrigate your crabapple seedlings as soon as they poke through the ground in spring. Place a shallow layer of mulch around the base of each plant to reduce water evaporation and weeds.