Why can you take seeds from an heirloom tomato and grow more tomatoes but it does not work with apple trees that have been on the property for 100 years? Are all apples trees garden centers sell grafted? I thought they just grafted to dwarf roots to keep certain species from getting too large.
The bottom line is that growing an apple tree from seed, although possible, will result in a tree that is quite different (and likely inferior) to the parent. On the other hand, if you plant heirloom tomato seeds, the tomatoes you grow should be true to the parent.
With fruit trees, the scion wood (which will produce the variety of apple you select) is grafted to a rootstock that is selected for a particular characteristic – e.g., size of tree, when the tree will bear fruit, hardiness and susceptibility to disease. See University of Minnesota’s Growing apples in the home garden. For Ontario-specific information on how to select rootstock and recommended apple varieties, see Government of Ontario’s Fruit trees in the home garden.
Growing apple trees from seed would not result in trees that had the same characteristics as the parent tree – seedling trees are usually inferior to the parent. But it can be done: see The Spruce: How to Grow an Apple Tree From Seed.
As for growing tomatoes from seed, heirloom seeds are open-pollinated and unlike hybrids, will grow true to type, as long as cross-pollination does not happen. See:
- Colorado State University Extension – Colorado Master Gardener. Tomatoes: Hybrid or Heirloom
- University of California Cooperative Extension. UCCE Master Gardeners of Sacramento County. Heirloom tomatoes.
The University of Georgia Extension’s Starting Plants From Seed for the Home Gardener discusses seed selection and variability among tomatoes grown from seed.