Seedlings emerge in spring or early summer, and growth is rapid under moist conditions. Mechanical scarification and the presence of low levels of nitrate appears to stimulate germination. Seedlings can emerge from soil depths to 10 cm. Seed from upper spikelets typically germinates within one year. Seed from lower spikelets germinates more slowly and can remain dormant for longer periods.
Light appears to inhibit germination and induce dormancy of seeds.
Burs on the soil surface can have a prolonged germination period of more than 3 years, but seedlings seldom establish. Most seed of buried burs germinates within 2 years. Plants emerging early in a season can produce more than 1,000 burs. Some seed is viable by the time flower spikes become visible. Sandburs compete poorly with dense vegetation and rarely become established in well-managed pastures.