I have done some research and found some sites suggesting alkaline soil while others say that alkaline soil will inhibit the growth of a cactus.

  • Do you have a specific species of Cactus in mind? I don't know cacti that well, but I know ph preferences in plants often vary species to species.
    – GardenerJ
    Commented Feb 20, 2017 at 13:05
  • Not really, I am just trying to figure out what soil they like most in general. I am planning on planting mixed cactus seeds so specifics do not matter so much.
    – user16651
    Commented Feb 20, 2017 at 13:30

1 Answer 1


Cacti grow best in acidic soil with a pH between 5 and 6.5. Watering cacti with alkaline water slowly raises the pH of the soil and can cause inhibited growth.

The exact level varies from species to species but as long as the soil is kept on the acidic side cacti will grow better.


  • This is a nice example of a self-answered question! Commented Feb 21, 2017 at 4:04
  • Truly a great question and answer TWA! I would have ASSUMED alkaline like most do. Reducing the pH of a soil is an awful lot tougher than raising the pH. Tap water shouldn't be used anyway because of all the salts and toxicity. How are you lowering the pH? How are you testing the pH? This might be a singular good way to use coffee grounds? Peat moss? Never ever thought about this before! PH is such a huge factor growing plants successfully. I've got a variety of different pH beds in my greenhouse just to accommodate this important aspect for different plants!! How about succulents?
    – stormy
    Commented Feb 21, 2017 at 19:03
  • I only recently started growing them indoors. Where I used to live in South Africa you could just plant them outdoors and they'd grow pretty well. Until now I have been mixing some coffee grounds with my potting soil and it seems to do the trick. If you can it is always better to water with rainwater (normally on the acidic side like +/- 6 pH) but this is not always possible for everybody.
    – user16651
    Commented Feb 22, 2017 at 7:06

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