I grew artichokes for the last 2 years. They are an annual in our zone, and to get them to set buds the first year, they need about 250 hours of temps under 50 degrees.
I started mine indoors in February, and as soon as they had their first set of true leaves, I transplanted them into deep 4" pots (they do grow taproots). Starting about mid-late March, I set the pots in the refrigerator every night for 8 hours, and did this for a month. That was the only way I could ensure that they got the 250 hours of cooler temps they needed. I finally planted them outdoors in mid-May (our last frost date is May 15), and 2 of my 3 plants got buds last year.
I think I needed to fertilize more, as I've read they are heavy feeders. My artichokes were on the smaller side, but I was still happy.
I've already got my plants started for this year. Germination is variable--I've had the best luck in a damp paper towel inside a baggie. The seeds that look more "white" in color generally do not germinate. I'm growing Imperial Star variety.
Good luck with your experiment!
