Yard and Garden: Germinating Tree Seeds

October 18, 2018, 1:35 pm | Richard Jauron, Willy Klein

AMES, Iowa – Starting trees from seed can be rewarding gardening activities, but tree seeds require a little more preparation than common flower and vegetable seeds. There are two ways to start tree seeds – the natural way, which often includes sowing the seeds in the fall, or through forced or assisted germination. Horticulturists with Iowa State University Extension and Outreach detail germination of several common Iowa tree seeds. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.

Hickory Nuts by Oleksandr/stock.adobe.com.How do I germinate hickory nuts?  

Hickory nuts need to be exposed to cold temperatures and moist conditions before they will germinate. (The cold-moist requirement is referred to as stratification.) The cold-moist requirement can be met by planting the nuts in the ground in fall. Plant the nuts .75 to 1.5 inches deep.

The cold-moist requirement can also be accomplished by placing the nuts in a moist mixture of sand and sphagnum peat moss and then storing them in a cold, 33 to 40 degree Fahrenheit location. Suitable containers include coffee cans, small plastic buckets and food storage bags. The refrigerator is a good storage location. The nuts must remain in the refrigerator for 90 to 120 days. After the nuts have been properly stratified, they can be removed from the refrigerator and planted outdoors in spring.  

How can I germinate buckeye seeds?  

The seeds of buckeyes and many tree species will not germinate until they are exposed to cold temperatures and moist conditions for three to four months. Outdoors, winter weather provides the necessary conditions to break dormancy. Gardeners can stratify seeds indoors by placing the seeds in a moist 50:50 mixture of sand and sphagnum peat moss. Suitable containers include coffee cans or large plastic jars. Punch holes in the lid of the container to provide air circulation. Stratify the seeds by placing them in the refrigerator at a temperature of 31 to 41 F for 120 days.

Plant buckeye seeds directly outdoors in fall or stratify seeds indoors over winter and plant in spring. When planting, place seeds 1 to 2 inches deep.            

How can I germinate redbud seeds?  

Redbud seeds have hard, impermeable seedcoats and dormant embryos. The seedcoats must be broken and dormancy overcome before redbud seeds can germinate.

The seedcoats on redbud seeds can be broken by submerging the seeds in boiling water for one minute. Dormancy can be overcome by subjecting the seeds to moisture and cold temperatures for a specific period of time. Place a small amount of moist, coarse sand in the bottom of a small plastic container or coffee can. Place the redbud seeds on the surface and then cover with additional moist sand. Punch two or three small holes in the plastic lid and then place it on the container. Place the container in the refrigerator for five to eight weeks. (The temperature should be 35 to 41 F.) After the cold-moist requirement has been met, remove the seeds from the refrigerator and plant indoors. Using a commercial potting mix, plant redbud seeds .25 to .5 inch deep. Keep the potting mix moist until the redbud seeds germinate. If the stratification period is begun in mid to late winter, the stratified seeds can be sown directly outdoors in spring.  

Photo: Hickory Nuts - Credit: Oleksandr/stock.adobe.com

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