Saving tree seeds

  • Published: Monday, March 2, 2020

Dedicated gardeners are often people who love to try new things. New plants, new varieties of familiar plants, new techniques ... they are always looking for a better way to grow a garden, orchard or landscape plants. Often this experimental nature expresses itself in starting woody plants from seed. This not only provides plants at a very low cost but provides a greater sense of accomplishment given that growers have raised the plant from a seedling.

For those of us with a severe case of this experimental disposition, fall weather brings on the temptation to save seeds from anything in sight. Fall is the time when most species have mature seed, and this is our main window of opportunity for woody plant seed gathering. To ensure success when planting them, seeds should be given proper handling. If they are gathered and stored in less-than-optimal conditions, germination rates may be poor when you plant them.

Actually, the best way to "store" them is to immediately plant them where you want them to grow. This duplicates the natural cycle that trees go through, with a little extra help on your part. Be aware that some seeds may have extra germination requirements, so this method could delay germination if those requirements are not met. If you need to store them indoors, place them in the refrigerator in a jar with a tight lid or in a sealed plastic bag. Keep them there until you are ready to plant in the spring.

If you are storing seeds that are surrounded by a fleshy fruit or berry, be sure to remove the fleshy part before storage. You can do this manually, or by letting the seeds sit in water for a few days until the fruit begins to decompose. This will allow the easy removal of the seed, but it is messy and definitely smelly.

The reason that you should keep the seeds in the refrigerator is that many seeds have a built-in period of dormancy. In the outdoors, this keeps them from germinating immediately in the fall, and going into winter as a young plant. These seeds must receive a certain number of hours at chilling temperatures before they will successfully germinate. Winter-long storage in the refrigerator will satisfy this requirement. Planting outdoors immediately after harvest will do this as well, and is less work.

If you are storing the seeds indoors, you should make sure the seeds do not dry out. During the period of refrigeration, moisture can be maintained by placing some peat moss inside the jar or bag. The moss should be moist, but not overly wet. Check periodically to ensure that the moisture level maintains a proper balance. The best temperature is around 36 degrees F. Slightly higher temperatures may be acceptable, but a longer time period will be needed to satisfy dormancy requirements.

When you plant the seed, it is best to plant directly where you want the plant to grow, thus avoiding transplanting. However, some people may prefer to start the plants in a nursery setting, where you may be able to give the plants a better start. An example would be the case where the soil at the final plant location might not be the best.

Generally, seeds do not have to be planted deeply. A good rule is to plant the seed about twice as deep as the seed's largest dimension. If planting in the fall, a cover of mulch to protect the seeds from winter extremes is helpful. Also, you may want to protect the seed from foraging wildlife by placing a wire mesh or basket over it.

Some seeds have specific needs. Acorns are an example. To avoid weevil damage, soak the acorns in water at 120 degrees F for 30 minutes to kill any weevils that may be inside. But be careful, since higher temperatures or longer times may kill the acorn as well. Other seeds may need to have their seed coat broken, so it pays to find out any specific requirements for the seed you want to plant.

One final caution: If you are saving seed from a particular variety of tree or shrub, you will probably be disappointed because the offspring plant may not resemble the parent plant. This is due the nature of genetics and the formation of the seed embryo after the flower is pollinated. This is particularly true of fruit trees. If you have a "Golden Delicious" apple tree and want another one, the only way to ensure this is through vegetative propagation, i.e., grafting. Trees grown from seeds in this case won't be true to type. You may get something similar, or something entirely different, depending on where the pollen came from that pollinated the flower.

Writer: Timothy Baker

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