Nyjer is a non-native plant. As such it really shouldn't be sown out-of-doors in that it may compete with native plants. Nyjer seed is imported and heat treated to not germinate. There is some good info. at the link I've provided.

Here is a link that might be useful: Nyjer Seed

Thanks for the response and the web link! I see now that it is considered a weed. That's too bad because the flower looked so pretty and I was thinking how much cheaper it would be to grow it myself!!! I was just outside trying to fix the brand new feeder I bought for the seed and already the squirrels have tried to rip it apart! They are such pests at my feeder. I don't mind them eating but I wish they wouldn't destroy things in the process!!
Joann

Here in New England people call nyjer "thistle", which seems a little strange to me, because it's not the seed of thistle plants. I've heard that nyjer seed is expensive and that it spoils relatively quickly, but that the Finches love it.

I don't feed nyjer, but I put black oil sunflower seed in a couple of small feeders, and these attract plenty of House finches, Goldfinches, and Purple finches, as well as other birds.

terrene, you'd be surprised at the number of people who have always called it thistle and think it comes from thistle plants. I cannot feed BOSS because of HOSP. They seem to love the stuff. Nyjer keeps well in the freezer. The Gold finches and House finches eat it pretty fast here.

The nyjer/nyger seed I buy for our goldfinches sprouts like mad in an uncultivated corner of the garden. I'm waiting to see what it's like when fully grown. At the moment it is just a lot of large, green leaves.

One year I could swear they sprouted ... but our season is not long enough to mature.