I mix 1 part native soil, 1 part cactus/palm mix, and 1 part compost to my backfill. The cactus/palm mix and compost improve drainage massively.

Most commerical cactus growers grow their plants in essentially a fast draining potting mix. When you're at Home Depot or Lowes, take a look and see what their big cacti are planted in.

Thanks, AJBB!

I guess another trip to Home Depot is in order today! :)

Most cacti don't want too much moisture-holding organic material in their soil, so I usually use either just native soil, or like AJBB mentioned, native soil mixed with some cactus/palm commercial soil. Definitely stay away from leafy compost and manures too. Sounds like you've got a good plan. Keep us posted!! Take care, Grant

Hi all,

Just a little update: my blue cactus appears to be doing okay. Although, he did just receive his first watering with the 3/4 inch rain we had the other night, so I am waiting to see if there are any signs of stress(none that I can see so far). Which brings me to my question:

What are signs of stress on a cactus like this? Particularly, I am concerned about the potential for root rot, since that seems to be the greatest threat (aside from frost once that day comes). Will it turn colors? I find cactus to be tricky in this regard...no leaves to give you an idea that something's wrong! Hmph.

I am guessing that since this isn't growing season, I should water it only sparingly (maybe once or twice a month tops?)? It's on the west side of my house so it does get as much sun as it can at least.

I wouldn't do anything. We get enough water in the winter to get your cactus established. If the cactus start to rot due to excessive water, it'll start turning yellow and then start dessicating.

Make sure to put a styrofoam cup on it before any frosts to minimize damage.

Yup, if it was mine, I would not water it again until you see serious signs of growth in spring when it warms up again. Nada, nothing, zilch. I water mine once every week to ten days when it's very hot out, and once a month when it's warm, then not at all November-March.

Good luck and keep us posted!
Take care,
Grant

I don't water cactus unless it shrinks, starts going limp or I want to speed up growth. Kind of depends on location too.

I plant in local soil, but I guess that would depend on the species.

Nurseries do have different issues and reasons for picking growing media. For example they want to water often, growth = $$$, so they need super drainage. Planting in the ground the drainage is less important unless it's planted where there's going to be a lot of watering. For my conditions the clay soil is helpful in holding moisture.

Root rot would be one issue. Another is fungus. In both cases I'd say by the time you see there's a problem it's probably too late.

Thanks, guys. I definitely will avoid watering!

However, one thing I'm wondering about drainage is:

I do have decorative rocks surrounding the cactus...maybe it would be better to rake them away to let the soil air out a bit (we got some more rain last night, and so I'm worried that it's not getting the chance to dry out)? The rocks are probably about an inch deep...not sure if they prevent water from evaporating? I also wonder if sprinkling or massaging corn meal into the surrounding soil might be helpful for prevention of fungus? Hmmm...

That's not an issue. You need to be concerned if the soil is still wet (not simply mildly damp) several inches below those rocks a week after it has rained. That's an indication that your roots are likely drowning in poorly draining soil.

Thanks again for the information, AJBB.

Hi All,
I am going to make a raised planter -- 24" high -- to plant about a dozen large totem pole cacti. the planter will measure about 10' x 12', so i'll need a lot of soil that's specific for cacti. Does anyone know a good, cheap source for this that will also deliver?

Native soil for the price of a shovel and some sweat.

This post was edited by Fascist_Nation on Sun, Aug 31, 14 at 11:43

I'm building a 18" tall planter and am planning some small cactus. I really don't have a clue on the soil.

I have one shallow terracotta container, 4-6" deep, 24" diameter that has clay soil from the yard which I've had small cactus in for about 8 years. I rarely ever watered it and one cactus did died, one almost died and one has done OK, but didn't increase in size. In the past couple of years I've watered it once in a while, few days in a row for many 3-5 days, and the 2 remaining cactus have done better, flowered.

On the other hand I have some cactus in very well drained soil, a mound like 3' high, 10' diameter. I didn't water for months and it started drooping which I take as a sign of lack of water, also diameter of plant was shrinking. So I watered some and they start looking better. I moved a drip next to one and I think it's rotted, but can't tell if that's from the watering or it actually was dying from lack of water.

I've found it very difficult to tell a good water amount. I do think water getting on the actual cactus or around the base is probably not good. Watering around the cactus seems to be safer.

For now I'm sticking with backyard soil. The clay holds the water which I think is good for a planter, but I let the soil dry out in between. I saw a nursery guy on TV say they water the cactus in pots everyday which with the well draining soil they use I guess is OK but would be bad for clay soil I think.

I'm still learning. Cactus seem to be super easy to grow and super easy to kill and they don't say much in between.