How to Germinate Robinia

Robinia is the botanical name for a group of trees and shrubs commonly known as locusts. Eight varieties of Robinia are native to North America, with black locust the most commonly cultivated and the most valued for its wood. The Robinia genus is in the bean family (Leguminosae), members of which typically fix nitrogen in the soil. Robinia seeds have a tough, outer seed coat that requires scarification to break its dormancy. Begin the process in late winter.

Things You'll Need

• Baby nail clippers
• Shallow bowl
• Small nursery pot
• Sand
• Heat mat

Instructions

1. Use a pair of baby nail clippers to pinch off a piece of each Robinia seed's outer seed coat. Don't cut too deep — just enough to allow water to penetrate to the embryo.

2. Heat water until it is hot to the touch and pour it into a shallow bowl. Place the Robinias seed in the water and let them soak for 48 hours. They should swell during this period. If they don't, cut the seed coats again and repeat the hot water soak.

3. Fill a small nursery pot with sand and set the Robinia seeds on the surface. Cover it with a 1/8-inch layer of moist sand.

4. Place the pot on a heat mat set at 86 degrees Fahrenheit. At sundown, lower the temperature to 68 degrees Fahrenheit. Raise it again to 86 in the morning. Continue this until the Robinia seeds germinate in 10 days to five weeks.

Tips & Warnings

• Keep the sand moist until the Robinia seeds germinate.

References

• Ohio State University Extension: Ohio Trees
• Plants For a Future; Robinia pseudoacacia - L.
• USDA Forest Service Seed Laboratory; Robinia L; David F. Olson Jr. et al.