Growing Salvia divinorum
Diviners' Sage, Ska Pastora
Natural Growing Conditions
Salvia divinorum is thought to be a cultivar - a plant existing only through the intervention of humans. It grows throughout the mountainous Oaxaca region of Mexico, and is cultivated by the Mazatec Indians for their divinatory and healing practices. It rarely, if ever sets seed in the wild. It propagates itself asexually. When plants reach about two metres in height they fall, and quickly root from points along the stem. In the high humidity environment in which it grows, it can be seen producing roots along the stems of fully erect plants.
As mentioned, Salvia divinorum rarely sets seed. Also, the seeds produced offer low viability. So, for the average cultivator, growing from seed is not an option. Fortunately, Salvia grows readily and vigorously from cuttings. Using a clean blade, cut a length of stem just below a node (a node is the joint-like area from which leaves grow). The cutting should consist of at least two nodes, and be at least 10cm in length. Once cut, strip leaves from the bottom node, and immediately place in sterilised water. Rooting hormone is not really necessary as Salvia roots readily; although if you have access to a Willow tree, one or two short twigs in the water may speed up the rooting process.
Rooting may take up to six weeks, although in warm weather, I have seen 3cm roots appear in ten days. Misting the cuttings will prevent the leaves from dropping, particularly when it is warm. Also, the water may need to be topped up once in a while.
Once the roots are 1-2cm in length, the cutting can be transferred to soil.
According to The Salvia Divimorum Grower's Guide, Salvia divinorum will flower if a photoperiod of 10 hours or less out of 24 is maintained (any light in the dark period will cause immediate cessation of flowering). This can be taken advantage of for maintaining vegetative growth by ensuring your plants receive 12 or more hours of light per day, up to a maximum of 18 hours in 24. Salvia divinorum is happy when grown under natural or fluorescent lights. Although expensive lighting equipment can be purchased for indoor growing, this is not necessary for the novice or average grower. If growing in natural light, do not grow in direct hot sunlight. Even if you have acclimatised your plants to accept hot and dry conditions, direct hot sunlight will cause stunted, warped leaf growth. If growing under fluorecsent light, hang lights about 30cm above the plants. Light can be saved and reused by placing reflective objects around the plants to reflect the light back, such as polystyrene or alluminium foil. Reflectors can also be placed above the lights to reflect back otherwise wasted light, please bear in mind any potential dangers from covering the top of your lights.
Potting / Re-potting
The roots of Salvia divinorum grow quickly, and in small pots, the plant will often become root bound, which may cause the plant to loose vigour. When this occurs, it is best to re-pot. You may notice some initial sluggish growth soon after re-potting as the plant first develops its roots, but soon growth and leaf production will become vigorous again. As with all plants, do not re-pot needlessly, as the plant will put too much of its energies into developing its roots, when it could be engaged in more important forms of vegetative growth.
Salvia divinorum is happy in ordinary house-plant potting compost. Ideally, the compost should be slightly acidic. A good mix would be; 3 parts compost and 1 part perlite. A layer of gravel or broken crocks on the bottom of the pot will also provide extra drainage. The gravel/crocks and perlite help prevent root rot by maintaining good drainage and aeration.