Cacti that don’t like high humidity

[Jaybizzle]

Is there a list of cacti/succulents that tend to not do well in high humidity/high temperatures?

I live in South Florida and most cacti do fairly well, but certain cacti aren’t growing much at all—e.g. Epithelantha, some Tephro species, etc.

Are there certain species to avoid, and any way to deal with the species that don’t like the humidity?

Thanks.

[Steve Johnson]

I have a small apartment collection representing only 64 species, so my experience is quite limited. The one species I'm growing that really doesn't like high humidity is Astrophytum myriostigma. Callused-over water blisters all over the place, so the plant has a pretty bad case of what I call "cactus acne". The rest of my Astros (asterias, capricorne, and 'capristigma') don't mind the humidity at all.

The fact that your Epithelanthas and Tephros aren't growing much might not be a humidity problem. The 2 things I look at are potting medium and fertilizer, so give me the details on:

• Ingredients and proportions of each ingredient in your mix.

• Fertilizer brand name and guaranteed analysis -- that'll be on the fert's labeling.

Once I know more about your mix and fert, I'll see if there's anything amiss.

[Jaybizzle]

Soil mix by eye—not much organic but some peat coir and bark. Granite grit Napa 8822 and limestone chips/gravel. This is limestone from Florida, so probably different from the limestone in habitat.

Water is alkaline so I add about 1TBS vinegar per 3 gallons water-gets water close to neutral.

Fertilizer not much—sometimes add the water soluble miracle Gro at low levels at watering.

Thanks.

[Steve Johnson]

There are a few problems with your mix, but unfortunately I don't have enough time to go through what the problems are and what you can do about it. I'll get into the details with you over the weekend if not before. In the meantime...

Miracle Gro is the worst fertilizer for cacti and succulents. Such being the case, read this:

viewtopic.php?t=47603

I realize the presentation contains a lot of info, but I think it'll be worth your time to go through it. If you have any questions there, let me know.