I really ought to have a bit more faith in myself. There I was a few weeks back, filled with doubt that my coriander seed-saving skills were up to scratch, and so I sowed my seeds really thickly, hoping that maybe a quarter of them might sprout.
Doubter! Now I feel foolish, because it looks like three-quarters of the little blighters want to enjoy the autumn sunshine, and now I have a two-inch high glut of too-much baby coriander to manage.
It's not a huge glut, it's still a small glut, but it's as crowded as a Hong Kong vegie market down there.
Late last year my coriander did what all coriander does when the weather warms up. It goes from leafy to flowery to seedy in the space of two weeks. So I let the plants go through their life cycle, waiting for them to then start dying down and the seeds to go from bright green to showing tinges of brown ... and then I pulled up the plants, snipped off the seed heads and put them in some brown paper bags and hung these up on a nail in my shed.
Totally forgot about them I did, but as autumn arrived I knew it was coriander seed planting time once the warm part of autumn was over.
Instead of painstakingly plucking individual seeds off the stems, I just closed up the bag and gave it a very good shake. Sure enough, a hundred or so seeds fell off and these were the ones I planted.
I use an easy method for planting them. I just clear a small patch of soil of weeds, dig it lightly with a fork to fluff up the soil, then I scatter the seed randomly, fairly thickly from my hand, medieval seed-sowing style. You know, just casting them out.
Then I get out a bag of seed-raising mix (it's a fine, sandy potting mix) and scatter this (also medieval-style) over the seed until you can't see them anymore. It does not need to be a thick layer of seed-raising mix. A quarter inch or about 5mm at best is all that's needed.
The huge, enormously difficult trick that you need to master is to remember to water the patch every morning, if rain isn't forecast. I use a light, fine spray setting on my hose attachment, so that the soil is well moistened but isn't washed away.
The seeds come up in about two weeks, and you'll have to wait another week or so before the seedlings send up those second pairs of leaves that actually look like coriander.
If you sow coriander seeds now, in autumn in temperate Australia, the plants should last you through the winter.
In my case, due to the excess of success, I will have to "thin out" my coriander patch, pulling out some plants to give the remaining plants room to grow. If you leave them overcrowded, your crop won't thrive, so you'll just have to do what farmers do, and manage your crops. Just pull out the smaller, weaker plants — Charles Darwin would want you to — to let the stronger, fitter plants thrive.
And PS: if you save seeds this way, you almost certainly will have saved more seeds than you could ever grow at your own place, so give the leftovers to your gardening friends.