Sowing fern spores - part 2

Half term is a time for many jobs, so although I'd hoped to do the actual sowing yesterday I just ran out of time. Today I've painted some garden furniture, been to the bank and also spent the afternoon digging over / building up a bed on the allotment. At last, this evening, I've some time for my ferns again. 

The spores are supplied wrapped in aluminium foil and when the packet is opened it looks like there's hardly anything there! All you see is a little bit of dust. Most of the spores I was sowing were Dryopteris spp. which all have dark spores, but I also had some Ophioglossum vulgatum which were a pale yellow. 

In this photo (pencil and tweezers for scale) you can just see the brown dust of the spores on the foil. The spores are single cells, so very very small. It's a miracle of nature that it works at all; when you think about it, most reproduction seems quite chancy, but it clearly works!

There are several recommended methods for transferring the spores onto the growing medium. I mostly tapped mine out, but I sometimes used a knife blade to lift them and tap them out as the small size of the spores means they easily become stuck to the foil - which might be static,  or might be capillary action/microstructure of the cell surfaces. Tapping out increases the risk of raising spores into the air and cross-contaminating between species, but I was careful to keep the plastic over the spores and to avoid sudden movements that could result in large air currents. I removed and discarded the paper towel and tapped the spores onto the surface of the growing medium. When I used a knife I was careful to clean it with isopropyl alcohol between sowing spores of different species. 

After sowing, I re-sealed the pots in their plastic bags. Labelling is crucial if you want to be sure what you've grown. I had 3D-printed some labels in advance - they were designed in SCAD and I added a pause point to the g-code so that I could swap out white for black when the lettering began to be printed. I might yet get round to uploading the design to Thingiverse if I can be bothered to tidy up my code a bit. 

I then placed all my pots on a north-facing window sill (the heating is now off for the summer, so they should be in no danger of over-heating).  

Over the coming weeks (from a fortnight to several months) I'll be looking for a green film to appear. Over time this should turn into a host of prothalli, the gametophyte generation. Sexual reproduction should then occur between the prothalli and new sporophytes (the stage we recognise as ferns) should begin. At least that's what should happen if it all works ...

I'll post some updates when I spot any changes.