Saffron is frequently called “the most expensive spice in the world”. Luckily for you and me, it’s not called that because it’s a pain the ass to grow (like, say, vanilla orchids), but because it’s a pain in the ass to harvest.
Saffron comes from a lovely little crocus, Crocus sativus. The spice itself is the plucked and dried flower stigmas (if you can remember high school biology at all, stigmas are the female parts of a flower and pistils are the male parts). According to my source “It takes 75,000 blossoms to produce just a pound of dried saffron threads that wholesale for $70 per ounce.” There are only as many as three stigmas in each flower, so growing saffron on a commercial scale also takes an enormous amount of land.
On a backyard scale, growing and harvesting saffron is a snap. These crocuses, like most others, are hardy and easy-going. They tolerate cold and have few pests and diseases. They grow from corms (like tiny bulbs) and will eventually naturalize (meaning that they will acclimate and spread as if native). A handful of corms is enough for most home growers to get the pinch of saffron they need for the occasional special dish. But there’s no reason you can’t pop these lovely little flowers into every nook and cranny of your yard and harvest enough saffron to give as gifts to the foodies on your holiday card list!
I had expected to pay through the nose for my initial investment in corms, but I was wrong. My saffron crocuses came from Pinetree Garden Seeds (♥) and a bag of fifteen corms was only $8.00!
 Hess, Clarke. “How to Grow Saffron” Originally published in Kitchen Gardener Magazine December 1997. Accessed online at http://www.vegetablegardener.com/item/2405/how-to-grow-saffron/page/all.