I'd say harvest whatever seed you can get from your own and sow asap in well draining but moisture retentive soil in a deep tray/pot and keep it outside. They need cold to sprout in spring.
They need to be sown deeper than you'd think 'cause in nature it's ants that drag the seed in their tunnels to eat the little 'thingie' (don't know the english term haha) that's on the seed.
Or you can just leave them to their own devices and let them self seed. They're really good at that though it takes a number of years to flower ofcourse.
After that you can split every reasonably sized clumps you have. In a few years you'll really start to bulk out this way alone!
A third way of getting alot of bulbs is twin scaling: dig up a few bulbs, cut off the top (growing point) end and any too long roots. Put the bulbs upside with the basal plate on the bottom and, using a sharp knife, cut the bulbs in half. Cut the halves again. You can do this as many times as you like. Ofcourse important thing is that every cut piece has a bit of the basal plate, otherwise no bulblets will form.
Put the cut pieces in a freezer bag with a moist medium (sharp sand, vermiculite, potting compost....), shake to cover and put them away something dark and warm for a few months. If done correctly little bulblets will have formed that can be potted up individually. They'll take a year or two to flower also.
Thoroughly sterilize any equipment you use, especially the knife.
(Google for more info
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