I have grown many cacti from seed - I would not have used Sphagnum Moss.

I basically use Schultz's or Hoffmann soil - give it a good soak, cover with plastic and put in a sunny window. Sun is less important that warmth at this point.

One possibility of a mistake - you could have covered the seed with too much dirt. With most cacti, just sprinkle them on the soil - don't bother to 'bury' them.

Cacti seed can be sow anytime of year - I prefer anytime, except late fall. Most will sprout in as little as 5 days, but give yourself 3 weeks.

Was it so moist that fungus developed on the soil? Keep moist, not muddy.

Cactus can bloom indoors if given enough light - but from seed - expect to wait a few YEARS.

I have baby pachycereus pringlei sprouts in an east window, no heating pad, planted March 11 and have about 10 sprouts. Some are threatening to show spines, but they just have their primary leaves. No more plastic, but I have other sprouts still with the plastic on - have one or two Pachypodium sprouts - but I always have a problem keeping them going.

Oh, and by the way, I have San Pedro sprouts from last year - still too tiny to transplant, along with Saguaros and Ferocactus Herrarae

Sagebrush.

If anything it was too moist. Also, I did bury the seeds.

I'm running out of seeds, but I'll try one more round with the cactus soil as you talk about.

So am I to expect that my little guy is going to have to live in the peat pot for a year before i can transplant?

Also, should I use dilute fertilizer as I would for other seedlings?

Thanks for the advice.

I have not had much luck growing cactuses from seeds, but that doesn't mean it can't be done. I'm impressed you got one seedling. You did something right!

Despite my limited knowledge of seedlings, I do have two San Pedro cactuses growing on my patio, one of which is about 3 feet tall. So I have some knowledge of caring for this species.

I think if you've gotten a seedling, it must be at least moderately happy, so presuming you don't encounter any other significant problems, I'd leave it alone until it's old enough to be transplanted. All things being equal, most cactuses generally do not need fertilizer, though there are fertilizers available that are specially made for cactuses. You can use those if you want, but follow the directions carefully. It's even a good idea to ask a knowledgable staffer at your store/nursery of choice about how best to use the fertilizer. A nursery that sells, or better, specializes in cactuses, might be your best bet, if you live near one.

San Pedro cactuses are hardier than your Sonoran Desert/Mexican varieties, but if you have your San Pedros outdoors in Zone 4, I'd still bring them inside no later than the late fall. Fortunately, San Pedro cactuses are one of the best cactuses to grow indoors, provided you give them enough light.

Like many other columnar cactuses, they like to spread their roots out far, so when you transplant, give your guy a pot that's at least as wide as it is deep. And although you want to water sparingly, San Pedros are much more tolerant than your average cactus of extra water, so if you get overly excited and water too much here and there, it should survive. But generally, like any cactus .... when in doubt, don't water. Let it dry out between waterings.

And San Pedro blossoms are rare. As I mentioned, the taller of my San Pedros is 3 feet tall, and it has never bloomed. And I live in Zone 9! (Phoenix)

One other thing - don't be too tempted about putting them outside in bright sun. They are babies and need protection from the sun. Best kept indoors in a south window if you have one, west and east are second best.

Of course, I have lost many a seedling by being overanxious about putting them outdoors.

Protect from strong sun! Indoor windows are fine.

Saguaros grow in the shade of nurse trees like Ironwood trees. When the trees die with age, the saguaros are grown up enough to handle the direct sun. Saguaros seeds that fall in hot sun will end up dying.

Find a nice pot you like and plan on keeping seedlings in it for the next two years. Avoid large pots, they like to be bunched up, their roots are not long at all.

If you want a 'fast' growing cactus (in cactus terms) - find a prickly pear fruit in the summer at your grocery. Eat it, enjoy it, spit out the seeds, wash them, dry them off and plant using my instructions and you have 'real' cacti by next summer. They'll sprout in 10 days or so and you'll see spines a few weeks after that.

Sagebrush