To propagate an Ostrich Fern, the most common method is to divide the crown (rhizome) in the spring when the plant is actively growing, as this fern spreads readily through underground rhizomes; you can also attempt to propagate from spores, though this method is less reliable and takes longer to establish new plants. 

Key points about propagating Ostrich Fern:

Division by rhizome:

Best time: Early spring. 

Process: Dig up the plant, carefully separate the rhizomes with a sharp knife or spade, and plant each division in a new location. 

Considerations: Ensure each division has a healthy growing point. 

Spore propagation (less reliable): 

Harvesting spores: Collect spores from mature, brown fertile fronds. 

Sowing: Sprinkle spores on a moist, sterile seed starting mix, cover lightly, and keep in a humid environment with indirect light. 

Patience needed: Germination from spores can take several weeks or months. 

Important factors to remember:

Moist conditions: Ostrich ferns thrive in damp soil, so ensure consistent moisture after propagation. 

Shady location: Plant new divisions in a partially shaded area. 

Controlling spread: Due to its aggressive growth habit, monitor and divide your Ostrich Fern regularly to prevent overspreading.