What I've Learned...

Nan's Nook : Archives : Botanicals : Cactus : San Pedro : Growing San Pedro : Soil
Posted by: ion Jun 17 03, 11:00 PM GMT
I got so fed up with taxonomical errors and indecisive info on everything about cacti that I went out and bought "The Cactus Family"... that $100 hardcover book by Dr. Anderson. I got it for around $50, though. biggrin.gif

Anyway... here's the deal:

You do want to mix your own soil.

The best soil for cacti must have the following properties:

"...drains like a seive, holds air like a ballon, and holds water like a sponge." -Anderson

Now, in order to accomplish every one of these things, you need a mix that has the following ingredients:

1 part organic material. This must be well-decomposed like compost or whatever.

2 parts aerator material. This can be chat (see max's posts), kiln-fired clay, perlite, rockwool, pumice, or just craggy pebbles of some sort.

1 part soil. This is where problems occur. Soil is different all over the globe, no matter what the brand-name is. You want dirt without too much clay in it. You can use commercial cactus soil mix for this if you don't mind working the acidity down (caused by the peat) with some lime... this may not be a problem if much of your aerator material is limestone.

The technical aspects of the soil:

pH. For these particular cacti, you want a pH between 7 and 8. The only reason you would want the pH to be near 8 is so that you don't have to mess with it very often. The ideal pH is 7... but that is very hard to maintain on a daily basis, so just make it a little basic to keep it out of the acid range.

Calcium. Cacti need this like they need sunlight, almost. The limestone should give you plenty, but you may want to add about a teaspoon of calcium chloride (the pellets we use to dry mushrooms wink.gif ) to 5 gallons of your fertilizer water just for shits and giggles... you want to apply this to the green flesh, directly, at night when the "pores" are open.

Magnesium. Almost as important as Calcium. It is usually included in fertilizers. This element is a part of dolomite (dolomitic limestone). Find it at the garden store and use it when you need to basify the soil. Or you could just add a bit of the pellets to your soil.

Micronutrients. Cacti love them. Add a capsule or crushed pill of chelated micronutrients to your 5 gallons of fertilizer water. It might smell funny...

Fertilizer. Normally, you would want less nitrogen (the first number in the 3-number group on the fert. bag.), more phosphorous (2nd number), and slightly less potassium than phosphorous. Something like 2-7-6. However, these elements may be all equal for pedros and peyotes because we want the nitrogen in order to build alkaloids... because these cacti make so much alkaloid, they can handle the extra nitrogen. So 20-20-20 will do just fine. Peter's makes an all-purpose fertilizer with some chelated micronutrients that is of this ratio... good stuff.

These are all optimals, of course. Do what you want. I can tell you this:

If you decide to go with some regular commercial mix and nothing else, you may be fine. You will have to be very careful not to over-water (acid soil will help the cacti rot in wet conditions), and you will have to watch the cacti very closely for disease. Fertilizing heavily is totally out of the question. Growth will be slower, but your cacti will probably do OK if you follow those 3 recommendations.


Posted by: HarveyWalbanger Jun 17 03, 11:13 PM GMT
I wub.gif you ion

Posted by: dustyclc Jun 17 03, 11:49 PM GMT
Nice bit of info ion. Thanks biggrin.gif

Posted by: ion Jun 18 03, 12:39 AM GMT
Aww... I wub.gif you, too, harvey. laugh.gif

Yer welcome, dusty. smile.gif

I think I'll add that graph, now...

Posted by: ion Jun 18 03, 12:43 AM GMT
Notice that the optimum range is ph 6 - 7... this is also true for most cacti, except that cacti begin to get very susceptible to disease at anything below 7... much more so than other plants do. This is why it is recommended to keep the pH up in the slightly basic range-- it strikes a balance between nutrient uptake and disease resistance. wink.gif


Posted by: Samsara Jun 18 03, 12:00 PM GMT
wub.gif wub.gif Ion your the bestest! Thanks! biggrin.gif

Posted by: Voodoo Jun 18 03, 05:21 PM GMT
Quick soil question.

When I water my cactus the water sits on the surface for quite a while. So I wouldnt exactly say its "like a seive." laugh.gif Should I repot them for more drainage? If so, what would be best to use? Im thinking perlite or just gravel. Let me know if Im way off base here. biggrin.gif

Posted by: MajorBuzz Jun 18 03, 07:30 PM GMT
Ion is amazing!

Posted by: Voodoo Jun 18 03, 09:09 PM GMT
QUOTE (Voodoo @ Jun 18 03, 05:21 PM GMT)
Quick soil question.

When I water my cactus the water sits on the surface for quite a while. So I wouldnt exactly say its "like a seive." laugh.gif Should I repot them for more drainage? If so, what would be best to use? Im thinking perlite or just gravel. Let me know if Im way off base here. biggrin.gif


Posted by: Voodoo Jun 19 03, 01:26 AM GMT

Anyone have any advice for me?

Posted by: Malformed Jun 19 03, 01:40 AM GMT
my pedro/peyote

is in a mixture of walmart soil, perlite, verm, peat

soaks up and holds water good all extra drains out fast, the roots seem to love it, and the cactus grows like i feed it steroids.

i try to let the soil dry out between waterings.

Posted by: ion Jun 19 03, 03:47 AM GMT
Like I said... anything seems to work. tongue.gif

However, voodoo, mal, and all of you fine growers out there... it is good (especially if using a soil containing peat) to re-pot your cacti at least once a year. You don't have to, but it is the best way to insure good nutrients and a lack of soil pests and harmful bacteria.

Let the soil dry. Wear gloves and have someone help you get the cactus and rootball out of the pot. Don't bend the cactus around, or jostle it too much... just slide it out nice and evenly.

Moisten the rootball a little with some clean water and very gently break it up with your fingers. Try not to harm the roots. Alternately, you can gently wash all of the soil from the roots with running water, but you may still need to poke a bit with your fingers... this is all kinda difficult to do without impaling yourself or harming the cactus.

Let the cactus lay out for a couple of days in the shade to let the roots dry. Lay it on a wooden table or something and let the roots hang over the edge... this keeps them from breaking at the bottom edge of the lying cactus.

Sterilize all pots with a 1 bleach to 10 water solution before planting in them.

Hover the cactus roots inside the new pot (use your friends wisely wink.gif ) and fill the pot with dry soil. Gently pack the soil down with flat fingers as you go.

You can use a garden stake to support the newly-potted cactus for a while... it won't be fully stable until the soil settles.

Leave the soil dry for about half a week, and then slowly re-introduce water. After wetting the soil and letting it dry a few times, the cactus should be stable.

These instructions work for all cacti, but are intended for larger ones. The only difference with smaller ones is that it is easier... you can usually do it with your own two hands and you shouldn't need the garden stake. wink.gif


Posted by: ion Jun 19 03, 03:48 AM GMT
BTW, throw some earthworms into your pots! biggrin.gif

Or at least some worm castings when you re-pot. wink.gif


Posted by: Samsara Jun 19 03, 12:03 PM GMT
Why would one leave the roots out to dry out? I know it would harm or kill any other kind of plant (stupid weird cacti exceptions!). What would happen if you re-potted without drying? Rot I presume?

Posted by: ion Jun 19 03, 09:49 PM GMT
Heh... they don't dry out completely. They just kinda get firmer on the outside so that they become tougher to break. In all honesty, you can do one or the other... dry in air, or dry in dirt... you don't need to do both. It is optimal to do both so that the roots are never shocked (with sudden water), that's all. The drying allows them to heal from the inevitable breakage that occurs during the re-potting process. If you were to pull them out wet, and then put them into wet soil, your chances of root rot happening will pretty much quadruple.


Posted by: Fungusmaximus Jun 19 03, 10:18 PM GMT
Hell I got my two grafted peyos sittin in concrete and they are thriving!
As Ion said, They will grow in anything.... tongue.gif wub.gif

Good info IOn wink.gif