Hello, and welcome to the fun world of cactus growing. It's easy and fun to watch your seedlings grow into maturity. You will need some simple materials and of course a good amount of patience. Since its so cheap you might as well sow a thousand seeds and one day become the new cactus king. Why not? I know you want to and it only takes 10-20 years. Don't believe me? Yahoo it!
So let's get started:
In this case we are starting with the La Mancha Seed starter kit.
To increase the chance of germination I recommend soaking your seeds in 3% Hydrogen peroxide for 10 min (optional).
Add growing medium into the provided pot and fill some water into a cup.
Place pot into the cup with water
After medium is saturated (One hour) sprinkle all the seeds evenly on the surface.
Place into provided plastic bag and tie a knot in the top
Thats it!
Put on the top and place by a window or use a t5 lamp or led bulb at room temperature.
Now comes the hardest part: Patience!
You should be able to see seeds germinate after about two to three weeks. Just put it away and forget about it. I know you want to look in there every day but nothing happens at this stage. You can leave them in there for up to a year and beyond before repotting. They like humidity when they are small. If you see green mold, open the container and spray with Hydrogen peroxide or alcohol. It will not hurt your seedlings but take care of any funkiness that may build up inside your container. It also helps to tape the sides with some opaque material to avoid light getting in.
And thats it! I wish you the best of luck. Hit me up if you run into any issues.
Happy growing