How to take care of your San Pedro Cactus
Growing San pedro's is easy especially since this cactus is very forgiving and only needs a little water and some nutrients. To grow healthy and happy they need well-draining soil, plenty of natural light, and a little water once in a while. You can grow them outdoors if you live in a temperate region, as long as the winters are not extremely cold (Zones 8b-10b).
SOIL
Fast draining soil of essence. You can buy ready made cactus soil or just mix equal amount of regular garden soil from the store with perlite or pumice. This will work fine just like this but if you want to ensure optimal growth you can also add a tablespoon of garden Gypsum to this mix.
LIGHT
They can grow in wide array of light conditions. They even thrive in direct sunlight. However, too much sun can cause sunburn leading to yellowing or browning. If you have intense Sun, let them get used to it slowly.
WATER
Ensure pots have drainage holes to prevent root rot. Water cacti when the soil is completely dry. Water thoroughly, allowing excess to drain out. In summer, this may be every 2 to 3 weeks.
Dormant Season
In the north Bay stop water in November and start again in March. Further south, like in Los Angeles you can water and fertilize year round.
FERTILIZATION
You can use any standard organic or regular fertilizer. The Ratio 10-10-10 works well for smaller plants and larger ones will do great with 4-7-7 or 2-7-7. Add one table spoon of gypsum every spring.
PROPAGATION
You can easily propagate San Pedro from offsets, which grow abundantly around mature plants.
To remove the offsets, make a clear cut with a sharp, clean knife. Place the fresh cutting on a piece of paper and let it dry out and callous for a few days. If you wish to root your cutting just place it in a container full of dry perlite or pumice.
Check for roots every few weeks. It can take up to four months for roots to form. Once you see roots you can just spot it in regular cactus soil and water as usual.