The dark art of propagating ferns from spores | Wow to | Gardening Australia

Ferns existed on earth long before the dinosaurs came and went. They've adapted to conditions all over the world, but to propagate them, well, propagating ferns is still a bit of a dark art.

Sue MacLaurin is one of just a handful of fern growers in the country and she shows Gardening Australia's Tino the secrets of her magic.

She explains that ferns don't have seeds or flowers, they produce spores, which can be seen in small sacks or lines on the backs of fronds. They turn dark brown or sometimes black when ripe.

Growing the spores takes time and patience but here are Sue's tips for getting started.

01:03 PROPAGATING FROM SPORES

You will need

A fern with ripe spores
A paper bag
Snips or secateurs
A sheet of white paper
Potting mix (Sue uses a mix of potting bark, sand, peat and perlite)
Face masks (for handing perlite)
Watering can
Boiling water
Zip-lock bag

What you do

02:18 Either snip off a frond with ripe spores and pop it in a paper bag, or place the bag under the frond and scrape the area to release the spore-holding sacks, called sporangia, into the bag.
After 4-5 days the sporangia will have dried and released the spores.
When dry, remove the fronds from the bag. The dust in the bottom contains both the spores, which in the sickle fern are yellow, and spore casings, which are brown.
03:25 To separate the spores from the casings, pour the mix onto a piece of white paper with a slight fold in the centre, and gently tap the spores and casings. The heavier casings should separate off and you can pour them off. If you’re worried about pouring off the spores as well, do this onto another sheet of paper so you can try again if it goes wrong.
03:45 Sue fills two containers, a tray and a pot. She creates a layered mix in the tray, putting perlite in the base for good drainage, topped by pure peat, tamped down to form a firm base. She fills the pot with the sieved mix of potting bark, sand and peat.
05:06 Both are then pasteurised by pouring boiling water into the watering can and pouring it over the tray and pot to kill off any pathogens in the mix. Sue makes sure the mix is fully wet, then pops a lid on the containers to stop any spores or fungi from getting in while the water cools - this takes about half an hour.
05:58 When it’s cool, sprinkle a tiny amount of spores over the growing mix, then place the whole pot in the ziplock bag, and label it. This should be put in a well-lit, warm space. It needs no more moisture until the spores germinate, which will take a couple of months; you’ll see a coating of tiny green ‘dust’ on the surface of the pot.
After 4-5 months they will have reached the ‘prothallus’ stage - a single-cell plantlet, usually heart shaped, which will create roots.
At this stage they start to reproduce and become a sporophyte. It is only when they reach this stage that they might need extra nutrition in the form of misting with half-strength seaweed solution.

08:07 PROPAGATING VEGETATIVELY

This can be done with ferns such as the hen and chickens fern (Asplenium bulbiferum), which forms little bulbils on top of the fronds.

Cut off a frond with some bulbils on it, and place it directly onto a tray filled with regular seed-raising medium, mixed with some perlite and slow-release fertiliser. Cover it with a fine layer of mix, just enough to weigh it down. Keep the mix moist, occasionally using half-strength seaweed solution.
The bulbils will anchor their roots into the soil and, in about three to four months, the new little ferns will be growing independently.

FEATURED PLANTS

Sickle fern (Pellaea falcata)

Hen and chickens fern (Asplenium bulbiferum ‘Autumn Beauty’)

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