Turbinicarpus jauernigii already flowered here and some others are forming buds now . And some do flower off and on all year . Miles2go in AZ usually has a good selection for sale off and on during the year.

hi Jerry, yea they don't like it at least for bonsai . years ago I noticed it caused fungus on my cactus seedlings so don't use it.

Might be fine in a dry place like Phoenix AZ ?

Question what do you do with all the hundreds of cactus you get ? assuming all goes well

Organic material in the substrate invites mold, so a purely mineral substrate with a layer of potting sand doesn't give the mold anything to feast on" I agree I don't use raw organic soil for cactus seeds and when I did its often with bad results. Be careful mold can grow on the seed coat itsel...

Conophytums I think you have to get them as big as possible in that fist 6 months so they survive Summer dormancy . last years seed were in mostly sand and they look mostly dead now but my new seedlings are looking good so far :D Lithops seem to be easier than conophytums from seed ? Cactus often th...

Yes first year flowers. the little one is the oldest and only survivor from a mixed seed package from mesa which had poor germination. It was my first try at conophytums back around 2018 ? I now have hundreds of tiny plants from my own seed they are not hard to germinate if you have good seed. I cou...

You can also water your soil mix in the pot and leave it out in the direct sunlight for a awhile ( weeks ) before planting cactus seeds. And Make sure your seeds are clean before planting .

Store bought soil mix works pretty good for tomato seeds, etc. I don't like it for cactus seeds.

If you spray a pesticide you should probably water in the evening or on a cloudy day

"the beneficial organisms in my custom soil mix would eventually be very important for the newly developing root systems" Probably crowds out the bad organisms. For a couple years I was having terrible luck growing cactus from seed or just growing them at all until I changed back to desert...

After using H₂O₂, how long do you wait to see if it's effective?" a day and it often doesn't work the plants will die by then. Best to avoid fungus if possible I tried strombocactus in a baggie and they all rotted , I don't use baggies much anymore . Will try again in the spring no baggie and I...

Looks like fungus , hydrogen peroxide might help I use it at 3% , dry powder fungicide might work better . maybe use a fan on the pot for a hour or whatever it takes to dry out the fungus and not the cactus.

Some seed grown conophytums not exactly sure of the species .

All looking very good

The Mammillaria hernandezii I got from you flowered

Winter bloomers yes I think almost all are . Pictures are somewhere on this website of many of them.