Sunday 5 June 2022

Growing ferns from spores at home

Years ago, back when I was in high school, I used to grow ferns from spores.  I am not really sure what varieties I grew as most I collected the spores from the bush when I was out collecting fire wood and grew them in my house as houseplants. 

Back then I found growing ferns from spores easy.  They just worked.  I think I accidentally stumbled on their preferred conditions back then.  

Bird nest fern sori contains millions of spores

Since then I have tried to grow fern spores a few times with mixed results.  Mostly I ran into issues either with spores never germinating, or contaminants overgrowing and killing the prothallus.

This year I am trying to grow ferns from spores again.  I have bird nest fern, maidenhair fern, and variegated maidenhair fern spores that I have collected from my plants.  

When I get a chance I plan to collect some tree fern spores and maybe a few other types of ferns to give them a try too.  If anyone wants to send me some fern spores, particularly from a stag horn fern, I would love to try to grow them.

Variegated maidenhair fern sori containing spores

I collected my spores on different days to prevent accidental contamination with the wrong spores.  I left the spores in paper somewhere dry and safe for a week.  

During this time I got everything ready.  

I used glass jars.  Why jars you ask, it is because I have them.  Containers with larger opening would be easier to get the young ferns out of.  While glass jars are not ideal I didn't have anything else on hand.

I poured boiling water in the jars and closed the lids, then left the to cool.  The boiling water sterilised the jars, and may have been an unnecessary step.  Sterilising the jars before putting in anything else doesn't hurt, so that's what I do.

Jars with peat moss, perlite, and fern spores
 

Once cool, I tipped out the water from the jar, put in a layer of perlite, added some damp peatmoss on top, and tipped in more boiling water.  I put the lids on and left them to cool overnight.  The boiling water sterilised everything in the jars.  

The next day (or a few days) later when everything was cool I removed a lid from a jar, sprinkled fern spores over the peatmoss, and put the lid back on tightly.  Fern spores are tiny and dust like so you can't plant them like seeds, you have to sprinkle them carefully.  I did one type of spore per jar, and did different jars on different days to reduce the risk of the wrong type of spore from floating in.

Spores need light to germinate, but direct sunlight will kill them.  It also takes anywhere from a few weeks to a several months for them to germinate.  I placed the fern spore jars in my greenhouse on a low shelf where they would receive bright indirect light.  

The jars were placed in a plastic ice cream container that had a bit of water in the bottom.  This step wasn't really needed, but the temperatures in my greenhouse fluctuate too rapidly for my liking.  The jars are sealed so no water can get in or out, which means the only thing the water in the ice cream container did was to help the temperatures remain a bit more stable.  

From here it is just a waiting game.  

It can take weeks to months for fern spores to germinate, so each jar was labelled to help me remember what is in each one.  There should be enough free water in the jars for the spores to germinate and do their thing. 

I also tried growing fern spores just using damp potting mix.  That seemed to work well, but it did have a lot more issues with moss, fungi, and other contaminates as you can see below.

Fern prothallus 

Sending up the first fronds

I plan to grow them all where they are for now.  Over winter their growth will go pretty slow.  In spring I will try to divide the survivors into their own little pots.  

I want to keep some of the baby ferns, and give some as gifts, any extra ferns will be listed on my for sale page.

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