Hardiness Zone: 6a
kandomom from Leavenworth, KS
I remember seeing some pictures of wild cacti growing outdoors in Kansas. They were a type of native Prickly Pear cactus, which are native to the United States (east of the Rocky Mountains) and can still be found growing in the wild in parts of the Midwest and Eastern U.S. Here is an interesting link with more information on native Prickly Pear cactus.
Depending on what kind of cacti you're trying to grow, the biggest obstacle you are likely to face when starting them from seed is patience. Some types of cacti can take up to a year to germinate, while others sprout in as little as a few days. Once you get them started, cacti are fun and relatively easy to grow. Just don't be in a hurry to see them reach maturity. At times, the rate at which they grow can seem impossibly slow. Then once you coax them into flowering, you'll be hooked for sure!
Most cacti grow best in full sun (to light shade) and prefer sandy soil. If your seeds are rated to grow outdoors in your zone, you'll want to start them now (April/May) so they have chance to grow and become established before winter. I would recommend starting them indoors where you can control germination conditions. Start them in shallow dishes filled with a moist, commercial cactus mix. Sprinkle the seeds on top, but don't cover them. Most succulents need light to germinate. Press them lightly into the soil with the bottom of a jar, just enough so they make contact with the soil. Some cactus seeds are fine-almost like dust. If you feel you need to, you can always sprinkle a tiny bit of sand over the top of the seeds to help anchor them. Cover the dish with a plastic bag to help keep the soil mix humid.
By Ellen Brown