Growing a plum tree from the pit found inside the fruit is possible, but it requires specific preparation and patience. This journey from a small seed to a mature tree is a multi-year commitment. The process begins with understanding the biological requirements of the plum seed, which must be tricked into believing it has survived a winter season before it will sprout.
Preparing the Plum Pit for Germination
The first step is thoroughly cleaning away all residual fruit pulp, which contains sugars that can attract mold and fungus during stratification. Next, the small, almond-shaped seed must be extracted from the hard outer shell, often called the endocarp, using a nutcracker or small hammer. Although some gardeners plant the whole pit, removing the seed significantly improves the chances of successful germination.
Plum seeds possess a natural dormancy mechanism that prevents them from sprouting prematurely. To break this dormancy, the seed requires a period of cold, moist conditions, a process known as cold stratification. This mimics the experience of a seed overwintering in the ground.
A simple and effective method for stratification involves placing the cleaned seed in a sealed plastic bag with a damp, but not soaking wet, medium like a paper towel, peat moss, or vermiculite. Place the bag in a refrigerator, maintaining a temperature between 34 and 40 degrees Fahrenheit (1 to 4 degrees Celsius). This chilling period typically needs to last between 10 and 12 weeks for the germination inhibitors within the seed to break down.
Check the seeds periodically during refrigeration to ensure the medium remains moist and to monitor for mold growth. If mold appears, the seed should be gently wiped clean and transferred to a fresh, damp medium. Once stratification is complete, the seed is ready to sprout, indicated by the emergence of a small white root.
Planting the Seed and Initial Growth
The best time to plant a stratified plum seed is in early spring, once the danger of hard frost has passed. You can start the seed indoors in a container or plant it directly outdoors. Starting indoors allows for more control over the immediate environment and provides protection for the young seedling.
A container for indoor planting should have adequate drainage holes and be filled with a well-draining soil mixture, such as potting soil combined with sand or perlite. Plant the plum seed shallowly, about 1 to 2 inches deep, ensuring the emerging root points downwards. Keep the soil consistently moist, similar to a wrung-out sponge, but never waterlogged, which can lead to rot.
Place the container in a location that receives at least six hours of direct sunlight each day to encourage robust growth. If planting directly outdoors, select a sunny spot with loamy, well-draining soil and plant the seed at a similar shallow depth. The seedling requires monitoring for consistent moisture and protection from pests, especially during its first few months.
Understanding the Long-Term Outcome
The most significant aspect of growing a plum tree from a pit is genetic variability; the resulting tree will likely not be “true to type.” Commercial plum trees are often hybrids, and their seeds carry a mix of genetic traits from both parent plants. Therefore, the fruit produced by the new tree will probably differ in size, flavor, color, and texture from the plum the pit originated from.
This genetic variability means the fruit could be better, worse, or simply different from the parent plum, and in some cases, the tree may produce inedible fruit. Commercial plum varieties are usually propagated through grafting, a technique where a branch from a known variety is fused onto the rootstock of another tree. Grafting ensures the new tree has the exact same fruit characteristics as the parent.
A plum tree grown from a seed requires a substantial time commitment before it begins to produce fruit. While grafted trees often start bearing fruit within three to five years, a plum tree grown from a pit typically takes between five and ten years to reach maturity. This extended wait is part of the natural life cycle for stone fruit trees started from seed.
Throughout the initial years, the young plum tree requires attention to structural development and health. Light, formative pruning is necessary to establish a strong central leader and well-spaced scaffold branches. Regular monitoring for common pests and diseases is necessary maintenance to ensure the tree remains vigorous as it works toward fruiting age.