Heirloom vegetables are older vegetable cultivars that some people prefer over hybrid cultivars for their flavor and their adaptability to local geographic challenges. Over the generations in which hybrid plants develop, farmers save the seed of only the hardiest heirloom plants. In this way, weaker traits are minimized and stronger traits accentuated. Plants that are not self-pollinating, such as corn or squash, are good candidates for cross pollination.
Prepare your garden by breaking up the soil with a rototiller or spade to a depth of 12 inches. Spread a 4-inch layer of soil amendments over your soil to a depth of 4 inches. Good soil amendments for a garden include compost, peat moss and manure. Work these amendments into the soil with a rake or your rototiller.
Plant heirloom vegetable seed in double rows in your garden. Plants placed in double rows are more likely to cross-pollinate from wind action or bees. Locate these vegetables far away from other varieties that may pollinate them accidentally. Popular varieties of heirloom vegetables include beans such as Kentucky Wonder or Scarlet Runner and corn such as Golden Bantam. Create furrows or drill holes with a rake. Place the seed into the soil at a depth that is twice as deep as the seed at its widest point. Cover with soil and water to germinate the seed.
Determine which plants are hardiest and best adapted to your local conditions. Collect pollen from the male part of these plants, which is usually the stamen of the plant, with a paintbrush. Brush the pollen over the female part of these plants, which is known as the pistil.
Save seed from the most flavorful vegetables when the seed fully ripens. Wash the seed and allow it to dry thoroughly. Store in a glass jar in a cool, dry location.