Planting guides for Annuals, Biennials, Perennials, Shrub & Vine seeds can be found at:
https://bloomoutlet.com/seed-guides/
Please read both the seed guide and this plant specific sowing instructions. If you are unsure of the best way to germinate the seeds, DO NOT SOW ALL THE SEEDS. Keep some in case the germination method you use doesn’t work.
ROBINIA PSEUDOACACIA - Black Locust
Sowing Instructions (Cliff Notes version): Additionally, read the “Seed Guide” for Shrubs/Vines
METHOD ONE:
Soak the seeds for 48 hours in warm water and sow in late winter in a cold frame. A short stratification improves germination rates and time. Prick out the seedlings into individual pots when large enough to handle and grow them in the greenhouse for their first winter. Plant them out into their permanent positions the following summer. Seeds can also be sown in an outdoor seed bed in spring.
METHOD TWO:
Scarify the seeds by placing them into hot water (almost boiling water) and let it sit for 24 hours. The seed will swell when scarified.
Optional: Apply a rhizobium inoculant. Rhizobium inoculant can be acquired by collecting surface soil from under healthy black locust trees and mixing this in your potting media. This is optional and not needed for germination but needed for good growth.
Mycorrhizal fungi in powder form can be applied to the seed after draining off the water prior to sowing.
Place the seed 1/4 in (6 mm) deep into a media consisting of 1 part perlite to 2 parts potting mix. Make sure the media drains well. If the media is too moist, fungus gnats can be a problem and can adversely affect the survival of the seedlings. Application of Gnatrol may be needed to control the fungus gnats and apply according to the label.
Once the seeds germinate, thin to 1 seedling per cell. For accelerated growth, use a heated tray or mat. Seed started in spring should have seedlings of adequate size for planting out in the fall or the following spring. Seeds can also be sown in the fall (September, October) and have seedlings for a June planting.
It is important to protect the seedlings from deer. If protected, the Black Locust can typically reach 5 to 9 feet tall after two growing seasons.
Botanical Name: Robinia pseudoacacia
Common Name: False acacia, Black Locust
Type: Deciduous tree. Fast growing tree for the first 30 years of its life.
Flower Color: White. Flowers are a rich source of nectar, very fragrant and has a vanilla-like scent
Flowering Season: Spring, Summer
Plant Height: up to 82 ft (25 m)
Plant Spread: up to 49 ft (15 m)
Light Requirements: Full Sun
Water Requirements: Average, Dry, Moist. Tolerates drought.
Soil Requirements: Sandy, Loamy, Heavy, Poor soils. Well-drained.
USDA Zones: 4-9