Size & Growth The San Pedro cactus is a fast-growing, multi-stemmed plant or small tree growing to measure approximately 5.9′ feet wide and up to 19.7′ feet tall. Individual stems range from 2.4″ to 5.9” inches thick and may have between 4 and 8 ribs each.

How long does a San Pedro cactus take to grow from seed?

The seeds will sprout in about one to two weeks. As the new San Pedro cacti start to sprout, poke a few holes in the bag every day or so until the bag has so many holes it is no longer effective at holding moisture in.

Do cactus grow fast or slow?

Most cactus grow slowly, sprouting to the size of a large marble after 6-12 months, and to a few centimeters in height after 2-3 years, depending on the species. After this, most cacti grow 1-3 cm in height per year. There are a few notable exceptions that can grow up to 15 centimeters or more in height per year.