Many trees can be grown from seed that is collected in your own backyard, but you should be prepared for what lies ahead. Plants may not come true from seed, so don’t be too disappointed if the new plants are not what you expected. In addition, many woody plant seeds require special treatment before they can germinate and grow new plants.
Many of our modern ornamental and fruit trees must be propagated by means other than seeds to ensure that specific characteristics will endure. These plants are more often propagated by cuttings, grafting or other vegetative methods that provide clones, or exact duplicates, of the mother plants. Reproduction by seed can be variable, and while the offspring may be similar to one or both parents, some desirable characteristics may be lost. Sprouting seeds from fruits purchased at the grocery can be particularly disappointing, since many of these fruits have come from growing areas that are very different than Indiana. These plants may not be able to withstand our growing conditions.
With fruit trees in particular, most commercially propagated fruit trees are grafted onto dwarfing rootstocks that are also disease and cold tolerant. Seedling offspring of these nursery-grown trees will not have the advantages of that dwarf rootstock. Standard size trees, particularly apple and pear, are very large and will quickly become unmanageable for the average gardener.
Most woody plants that grow in our climate bear seeds that are dormant and must go through some physiological maturation before they will be able to germinate. These changes are often referred to as “after ripening.” The most common type of dormancy is overcome by moist-chilling, also called stratification. In nature, seeds are stratified by laying in cold, moist soil over winter, but they may never actually germinate. The seeds may become buried too deep, damaged by insects and animals, or excessively dry.
Gardeners can stratify seeds in a more controlled manner by placing the seeds in moist packing material, such as peat moss, vermiculite or sand. The refrigerator is just about the right temperature to provide the chilling. Although the length of the chilling period varies with the plant species, most seeds are adequately stratified for three to four months at 35-40 F.
After the chilling period, these seeds can be sown in pots, flats or other suitable containers using a loose, well-drained media, such as a mixture of peat moss and vermiculite. Maintaining high moisture and relative humidity is crucial to germinating the seeds. You can raise relative humidity by enclosing the seed tray in a plastic tent. But be sure to poke some holes through the plastic to ensure air circulation. Keep the trays in a warm, but dimly lit location.
Germination can be as quick as a few days or as slow as several months, depending on the species and environmental conditions. Once the seeds germinate, move the seedlings to a brighter area. You may need to “nurse” the seedlings indoors for several months before planting outdoors. Try to give the young plants as much light as possible, and feed with a houseplant type fertilizer according to label directions.
Home-grown seedlings may not be prize-winners, but they can provide a fun project for the adventurous gardener. Other special handling techniques may be needed in a few species. If you’re truly interested in experimenting with home-grown trees, take a trip to your library, and become more familiar with the individual species. Ask the reference librarian for the following books: “Seeds of Woody Plants in the United States,” Forest Service, USDA Agriculture Handbook No. 450; “Plant Propagation,” Hartman and Kester, Prentice Hall; or “The Reference Manual of Woody Plant Propagation,” Dirr and Heuser, Varsity Press, Athens Ga.