fern propagation

 Brian Aiken, the curator for the American Fern Society spore exchange program, has generously shared his techniques for spore harvesting / culturing and fern identification.   

Fern Lifecycle

What are spores?

How to collect spores

- American Fern Society (AFS)

- British Pteridological Society BPS

American Fern Society fern propagation / spore viability test

Spores are sown on sterilized Pro-Mix HP soil or hydroponic agar and maintained for 8-16 weeks at room temperature 11 inches below two 20W cool white, fluorescent tubes (or equivalent) illuminated 14 hours per day.

I have been using clear, plastic or glass food storage containers containing PRO-MIX HP MYCORRHIZAE™ as my substrate and potting soil for young plants. This medium is a high porosity peat-based growing medium containing, beneficial mycorrhizal inoculum (Glomus intraradices). This formula ensures optimum growth, especially when high air capacity and extra drainage are required. It is ideal for water sensitive crops, rooting cutting and/or low-light growing conditions.

When to collect spores

Advice from the British Pteridological Society

Brooklyn Botanical Garden propagating ferns from spores 

Ferns propagated from spores at Walmer Woodlands

1. Ctenitis subglandulosa 'so fine', fronds harvested 9/5/23 with Dr. Pat MacMillan at JLBG, stored at 40 degrees F, spores isolated and cultured on Sphagnum peat moss 10/2/23
2. Polystichum acrostichoides, Christmas Fern (NC Native) 
3. Dryopteris erythrosora, Autumn Fern (Introduced)
4. Dryopteris marginalis, Marginal Wood Fern (NC Native), spores collected 7/20 by BA at AFS (1064), stored in refrigerator, dry, cultured on sterilized Pro-Mix HP 1/22/24 , #11
5. Homalosorus pycnocarpos, Glade Fern (NC Native), fronds collected 9/5/23 by dkw at JLBG with Pat McMillan, cultured on sterilized Pro-Mix HP 7/4/23 (culture #3), prothalli appeared in 14 days 7/18/23, first fern fronds appeared 83 days after the prothalli appeared 12/29/23, this species was challenging to harden, ferns planted outside in freshly mulched garden 5/23/24, squirrels dug through mulch and destroyed young ferns, 42 ferns sold to NCBG 9/30/2024
6. Onoclea sensibilis, Sensitive Fern (NC Native)
7. Osmunda claytoniana, Interrupted Fern (NC Native), spores collected 05/2023 by BA at AFS (1390), stored in freezer, dry, cultured at ww on sterilized Pro-Mix HP January 21, 2024, ww culure #7
8. Osmunda regalis, Royal Fern (NC Native)
9. Osmundastrum cinnamomeum, Cinnamon Fern (NC Native), spores collected 5/23 by BA at AFS (1389), stored in freezer, dry, cultured on sterilized Pro-Mix HP 1/21/24, #8
10. Polypodium virginianum, Rock Polypody (NC Native)
11. Polystichum munitum, Western Sword Fern
12. Thelypteris palustris, Marsh Fern (NC Native)
13. Woodwardia areolata, Netted Chain Fern (NC Native)
14. Woodsia obtusa, Blunt-lobed Cliff Fern (NC Native)