Raising Ferns From Spores

Now here’s a post that has been 18 months in the making and that is, “the growing of ferns from spores”. Ferns are such ancient plants that flowers and seeds hadn’t evolved when ferns were first around and so spores were the way to propagate. There is a mystery surrounding the way ferns propagate and the methods involved. There’s sterilising the compost, using brick dust, sheets of glass and so on. I read several articles on “how to grow ferns from spores” and eventually concluded, “ain’t nobody got time for that!”. However, I’m always willing to “give things a go”, so I thought I would try raising ferns from spores, my way. The whole exercise was budget driven, I don’t want to pay £8 per fern when I’m going to need lots for the new garden.

In the summer of 2014, the very year we moved into the new house and garden, the side border was completely renovated and among one of the several plants that went in was a fern. I’m not sure of the variety and type etc, it was just a “standard” green fern. The new border established well and around late summer, when catching up with progress and doing the “is it dead?” check, I saw the undersides of this fern were brown with spores, the whole thing looked diseased, it was awful but it sparked the idea of seeing if I could get just some of these millions of spores to turn into new ferns for free. So I grabbed a seed tray, filled it with compost from a new bag (so it would be pretty sterile), drenched it with water until it was saturated and placed a fern frond – spore side down – on top. The frond was flat and made good contact with the wet compost. Over the top I put a clear plastic meat tray (washed, of course) to make a mini greenhouse. I put this in permanent shade and left it for a several weeks.

The emphasis when growing ferns from spores is cleanliness and hygiene. This is why articles refer to sterilising compost and using brick dust, which is sterile, and not using rain water etc. I used a washed seed tray, compost from a new bag and didn’t bother with the brick dust to put the spores on. Obviously I washed the meat tray and used water from the hose. I didn’t bother cleaning the fern frond either. Growing from spores takes a long time and as the conditions need to be continually damp, you’re much more likely to end up growing moulds and moss, which will overwhelm the fern spores. In practice, I made a reasonable effort to keep things clean but not anywhere near what some articles recommended.

Going back to the fern frond on the seed tray after a few weeks, I took a peek, removed the leaf, which left in place an imprint made of settled spores. I gave the tray a gentle misting with water (the joys of having a multi-selection hose end). Replacing the lid again I left the tray in the shade for several more weeks, which then turned into the best part of two months.

By mid-autumn 2014, the surface of the soil was covered with something green that definitely did not look like ferns:

These are not young ferns or ferns germinating, there are no ferns. This is stage before ferns, these countless tiny green plates that look like miniature seed leaves are called, “Prothallia” and contain the sperm and the egg of future fern. As someone who is used to planting seeds and seeing one plant come from one seed without this intermediate stage, the whole process feels very alien. Note you can also see a little moss and mould growing too, there were sections of the tray that had become overrun with it so I took them out before they spread too far.

The next stage is waiting for fertilisation to take place and for the first new fern fronds to grow. This part is slow, very slow. It may have been due to winter arriving but it was late November by the time the first clear signs of fern fronds were visible:

The bright little green leaves on the background of dark green are the first tiny little fronds of newly “germinated” ferns. These came through the winter and continued to grow in their seed tray the next season. More and more little new ferns appeared and by around mid-summer, 2015 (a year after starting), they were crowded enough to be split into tea-spoon sized clumps and put into mushroom trays (with holes in the bottom). They continued to grow and by autumn, they were clearly recognisable as distinct young ferns:

It was a rather delicate operation to try and split these further and pot them up before winter but we managed and the young ferns really took off and are now keeping warm (relatively) in the greenhouse. There are still many ferns per pot but I expect the smaller ones will be out-competed by the larger ones. I’m not sure if or how the ferns can be split further, but I think there are enough to be getting on with at the moment.

Now in 2016, the young ferns continue to shelter in the greenhouse and by this summer – two years after starting – they will probably be large enough to be planted out in the garden. They will probably end up in the various shady corners of the borders and underneath newly planted shrubs. With the garden being on the wet side, I’m hoping they will thrive.

The next project will be try repeat this with Japanese Painted ferns. Growing ferns from spores wasn’t nearly as daunting as it first seemed to be from reading. There is a lot of waiting, watching and wondering involved and I don’t know if I got “beginner’s luck”, but it was well worth the chance given the number of ferns we now have from just one frond.