Sowing spores

Sow the spores thinly onto the surface of rather damp soil. There are a few important points to keep in mind when sowing spores:

1. You must sterilise the growing medium or you will have problems of competition from algae and mosses. This can be done with boiling water or in a microwave. If you use a microwave you need to be really sure there are no stones in the soil as they may explode in your microwave. The growth medium should be fitted to the needs of the species.

2. For all species you need to maintain reasonably high humidity. This is best done by sowing into 5 cm pots and then sealing in plastic bags.

3. Don't sow the spores too thickly. If you do the gametophytes that develop will be slower to grow and will only develop male sex cells.

4. Most species need good but not direct light. I have killed gametophytes with cold, flooding and drought but not with heat (yet!). They grow much faster in the warm (l5º C).

5. In the unlikely event that you get no results from a pot, do not throw it out! There is increasing evidence that like seeds, fern spores have dormancy mechanisms (Sheffield, 1996). Unfortunately almost nothing is known about the extent or nature of these. I have found growth starting in pots 8 months after sowing. Your best bet is to experiment. Move the pots to a different aspect, add more water, let them dry out, just have fun finding out.

6. If you fancy having a go at propagating some exotic fern you have in your house a good guiding rule is that spores should be sown into a slightly damper version of the environment that the parent plant has done so well in.

• What will happen next?
  The spores will start to germinate within a week. Within 3 weeks the surface of the growing medium will be covered in a green fuzz and look for all the world like a rather small billiards table. From this fuzz the characteristic heart shaped gametophytes will slowly emerge. Depending on the species, time of year and growing temperature, tiny sporophytes will appear within about one year. Some slow-growing species may take two years to produce sporophytes. I have found that the best survival at potting on is achieved if you wait for the sporophytes to be about 3-4 cm high. If you wait any longer the sporophytes in your sowing pot will compete with each other and self-thin. Any sooner and the plants are too fragile to survive handling and root disturbance. If anybody reading this has any good ideas on transplanting gametophytes I would like to hear them... Your fern should be identifiable within a year and a half or so. Do not be surprised if you find strangers in your carefully labelled pots. Spores are minute and very readily transferred from one pot to another during sowing.

Thank: Tim Dickinson