I collected spores from Dryopteris dilatata in northern Germany, the last fronds that didn’t spore yet that I could fine this time of year. Considering that it’s 10-ish°C here right now do I sow them outside or inside? Or should I wait? And also, is using just one frond (or at least from a single plant) incest? Will they be “less healthy”?
by fracgen
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I can speak to this! You came to the right place. I have propagated a number of wild ferns from spores, including *Dryopteris intermedia* and *Dryopteris carthusiana* (though admittedly not *D. dilatata*, but many species seem to follow the same rules).
You will be pleased to hear that a surprising number of wild ferns are not hard to propagate from spore. I have not tried to grow the spores outside, but they are quite easy to grow inside on basic potting medium. It can often be done right away… which is confusing, since you would think they would have to have some kind of winter dormancy. But then again, spores have few energy reserves… maybe they can’t wait? I don’t know what they do outside. Regardless, you can grow them now indoors, and have little ferns for planting next summer.
The key is to keep the soil moist, ideally with the pot in a humidity bag like a ziploc bag, lit with good light but not in direct sun where they would overheat, and to be patient. Read up on the fern life cycle (if you haven’t already) so you know what to expect. It may take several months to grow the gametophytes to size and then pass through the gametophyte to sporophyte phase, but trust the process. Keep them humid, and maybe spritz them with water when the gametophytes are developed to help them transfer sperm.
To harvest the spores for this, you can leave the leaves between sheets of paper and let them dry out, then when the spores fall out onto the paper you can tap those spores off the paper into the potting soil. Alternatively, using a knife to scrape off the sori into the soil also works. If possible, yes, I would get multiple fronds from different plants to try and get a healthy genetic mixture, though I would note that you *can* complete the process with a single frond. It just won’t be as diverse a genetic mixture, and would be more inbred. Inbred plants may grow to be quite healthy, though it is a good idea to opt for genetic diversity where possible.
Once you have tiny sporophytes forming, you can dig them out with a small tool like a spoon handle, and plant them into larger pots. Fern propagation will produce a “moss-like” layer of gametophytes, and many of these will produce sporophytes, so you ought to have many, many baby ferns you can pot up into larger pots, likely more than you will need. It’s really easy to use this method to grow large numbers of ferns.
I’ve managed to propagate a bunch of native ferns, even rock ferns like *Asplenium rhizophyllum* and *A. trichomanes*, fen ferns like *Woodwardia virginica*, and wetland ferns like *Onoclea sensibilis*. Most (even the rock ferns) can be propagated on potting soil. I’ve never succeeded with species in the Ophioglossaceae, but I later learned that these are mycorrhizal and their gametophytes are subterranean, and may not produce emergent fronds for over a year! Meaning you would need a complicated setup to grow them indoors. I failed to grow *Dryopteris goldieana*, but I think I got the fronds when they were too decayed and the spores might have been bad. *Asplenium viridis* also did not work, though given its very specific habitat I wonder if I didn’t replicate the habitat well enough.
If you do try, just remember, keep the soil moist (not submerged, but moist), in indirect light, cover in a humidity bag, and above all, don’t give up on it. Fern spores take time to grow. Trust the process. Wait for the mossy layer of gametophytes to mature, then wait for the sporophyte fronds to form. I just tried a species that took a full year to produce sporophytes! I don’t know your species, but if it’s like *D. intermedia*, it shouldn’t take that long – as I said, probably several months.
Good luck! Have fun