Salvia divinorum propagation
Light & temperature requirements
Salvia divinorum in its natural environment in the mexican rainforests only receives 20 to 50% sunlight. The dense canopy of the rainforest filters this light at all times and the plants are never exposed to stronger light. They are fully adapted to these conditions and cannot cope well with light intensities much higher than 50%. In the garden environment this can be provided by placing the plants under dense trees under 50% shadecloth. Established salvia plants will survive stronger exposure, but this will stifle growth and decrease leaf size. Young salvias or salvia cutting are best kept under artificial lights. These should be cool white fluorescent tubes, as the heat emitted by HPS or halide bulbs is damaging to salvia. If these warm light sources are the only option, the plant should be placed at least 2 or 3 meters away from the bulb. Salvia prefers temperatures around 20deg C. It will withstand much higher temperatures (up to 48 degC), but only in very high humidity environments. Temperatures below 10 degC will trigger dormancy. Salvias flowering cycle is induced by short photoperiods. When light hours fall below about 12 hours in autumn, vegetative growth will cease and flower poduction will proceed rapidly. For continous growth under artificial light the hours should be kept above 16 at all times. It appears that salvia does not need a dark period and 24 hour continuous lighting resulted in increased leaf production.
Soil, water and nutrient requirements
The rainforest soils of the natural habitat of Salvia divinorum are very fertile and rich in organic matter. Salvia generally chooses very damp or even wet places to grow and is frequently found along mountain creeks and gullies. The soils can be heavy or light but are always very rich. Salvia responds well to high nutrient levels. It has come to my attention, that salvia is extremely snesitive to ammonia gas. This can be produced when manures or urea fertilisers are exposed to heat. A build up of these gases will kill the foliage of the plant and may do damage to the growth nodes. A good way to avoid this build up is to always provide some form of ventilation. In propagation domes this is should be the top vent hole and with 'plastic-bottle-hothouses' the lid should always be left off. Cuttings and houng plants are best fertilised with s alow release (osmocote) fertiliser or with seaweed extract.
Salvia divinorum rarely produces seed. It is very successful at propagating by vegetative means, that is has propbably lost its ability to produce seed. It may also be possible that Salvia divinorum is a hybrid and has become self sterile in the hybridisation process. Little is known about hte true reasons for its low seed production. In nature, virtually no seed is roduced, but handpoliination can remedy this. The seed produced this way has a very low viability and this is not a recommended way of propagating salvia divinorum. In its natural habitat the plant grow to a height beyond what it can support and falls over. The length of the stem that is now touching the ground will form roots and new vertical shoots will emerge from the node axils. It will continue to do this every few weeks and can cover substantial areas this way. As the plant prefers to grow near water courses, it is inevitable that small sections get brokn off occasionally and get washed further down the stream. As these lodge on the bank or in rocks they will root and start a new patch.
When you receive your cuttings, make sure that there is no rot on them. The young leaves and new green shoots are the most likely to rot, especially if they've spent several weeks in the mail system on overseas trips. The sphagnum moss your cuttings are packed in contains natural fungicides and a lot of moisture, both of which prolong the storage life considerably. Cuttings will easily survive 2-3 weeks in these condition, but even after 5 weeks they have come out alright. If you are not ready to strike your cuttings straight away, please maintain them in the closed bag they came in. Cuttings to be rooted should be free of mould or rotting parts.
It is likely that the salvia cuttings have already formed small roots by the time they arrive. Small nodes or even longer strands may be visible along the full stem section that was in contact with the moist medium. Salvia cuttings do not need to root from a node!! Most other plants need one node to root from and another to grow from. Salvia only needs the one to grow from, as the roots will be formed along the internodal stem section. It is best to use a slightly woody cutting, as these have greater energy reserves and are also less likely to succumb to fungal problems.
There are many methods on the internet on how to root salvia. Most are quite easy. Some are better than others. We only use one method, because we have had virtually 100% success. It involves placing the cutting into a mixture of perlite and vermiculite under a humidity dome or inside a humidhouse. The medium mixture should not exceed 10%vermiculite and should be made fresh for every batch. Start by mixing 90% perlite with 10% vermiculite (by volume), placing it into a propagation tray and wetting it thoroughly. Now take a stem section and cut it to a toatl length of 12 cm, with a node at the top. Insert this into the medium with the node up. Place a humidity dome over the tray and place the tray into 20% cool white light (fluorescents). direct sunlight or strong indirect sunlight is not appropriate here. Most people kill their cuttings by providing too much light or too much heat.
A cheap and easy hothouse can be made from a softdrink bottle. This is possibly the most perfect way to establish your cuttings. The bottle used should be at least 500ml. If it is larger than 1l, then the air might be a little too dry for the cutting, but it will still work. Choose a pot with a diameter a little larger than the diameter of your bottle. Fill the pot with a mix of 90% perlite and 10% vermiculite (by volume, ie. 9 cups perlite and one cup vermiculite), and place the single node cutting at least 3 cm into the medium (note: plant shown here is NOT a salvia - this method can be applied to may different plants). Cut the bottom off the CLEAN plastic bottle and push it about 2-3 cm into the medium. The plastic cap can be used to adjust the humidity and temperature inside this min-hothouse. For salvia it is advisable to never close the vent completely, but for the first couple of weeks it is best to cover the hole partially to increase humidity. Place only one cutting per unit to avoid overcrowding. Watering can be done throught hole, or the bottle removed for maintainance.
Looking after potted plants
Most collectors will start their plants in pots as these can be placed into appropriate conditions without disturbing the roots. Salvia likes a lot of nutrients and will need plenty of root space. Make sure that the soil never dries out as salvia has no protection from excessive transpiration. Once well established the plants will not mind having 'wet feet' and this may be a suitable way of ensuring permanent water provision. Plants can also be hardened off to survive in non-humid conditions. To do this without stressing the plant too much, remove all the leaves from the well established plant, leaving only the tiny growing tips. Now place this plant into a dry but shady spot and always water it well. As the new leaves grow they will be much harder and heavier. In very dry and hot conditions they will be somewhat deformed and will show browning around the edges. The growthrate will be much slower, but the plant will be much easier to take care off.
Disclaimer: All seed is sold for botanical preservation purposes only. All parts of this plant can be toxic and should not be ingested.