Root Rot: If a plant is
rotting at the roots, - dying from the base up, it's fairly safe
to say it's a goner. The best course of action is to take as many
cutting as you can. Cuttings from the top of the plant stand the
best chance of being rot free. Rooting the cuttings in separate
containers will isolate good from bad and improve over all
chances of success, but you should do this anyway (see advice on
cuttings).
Branches Dying: If a plant appears to
be dying from the tips of a branch, shedding leaves, with the branch turning brown and eventually
dying off, this is not necessarily as serious as it first may seem. It could do this at the
summer's end, or just anytime. A good example would be where the growth of
leaf on other branches nearer the light source had the effect of blocking out
light to lower / further back branches and leaves. In a case such as this, the
plant may decide that the game isn't worth the candle and effectively close
down operations and redirect it's resource to producing shoots and leaves
elsewhere.
Having said that, if this doesn't ring true in your case, if more branches
keep dying and your plant does not appear to be making any progress (i.e. when
you would expect it to be growing), then it could be that the plant is
otherwise unhappy. It may need re-potting. It may be too dry. Check the rest
of the plant care advice to see if its over all circumstances could be improved.
Leaf Condition: A little leaf yellowing, or browning and mottling, or
drying at the edges, again may not be too much to worry about. Rather like the
advice for branches dying, this can be simply the plant adapting to its
situation. For example yellowing leaf not getting enough sun, being crowded
out by growth elsewhere.
The intuitive conclusion for leaf drying and browning is that the humidity
is too low. However, before you take the decision that you simply must have a
humidity tent, consider other factors too. If the plant has plenty of good
leaf on it, and just a few browning in one particular area, then, as with the
advice above, this could just be the result of these leaves being shaded
out, - this would be particularly true for mottling leaves.
Conversely, truer for leaf drying at the edges, it could be a result of the
leaves being too much at the forefront in direct sunlight and suffering while
they provide shade for the others. Check the rest of the plant care advice and
see if other factors could be improved. If the weather has been unusually dry,
i.e. it's not your normal conditions, then you could attend to them with a
spray misting gun and also water them a bit more.
A final and very important point to emphasise here is that the leaves do
not last forever. It doesn't matter how ideal your conditions are, the
leaf has a life-span. Older leaf will become mottled and dry and lose
it's colour before eventually dropping from the plant. This is not
something to worry about when you have new growth happening elsewhere. I
think the older leaf is better for smoking by the way. It doesn't seem
to lose its potency and seems to burn sweeter and smoother than young
leaf.
Pests: Salvia
divinorum is supposedly a bit vulnerable to pests such as whitefly. This can
be more of a problem with having a humidity tent, which can turn out to be a
breeding ground for little bugs. As said in the watering section, but worth
mentioning again, another thing that I do is I tend to water
the plants from the bottom, that is, by adding water to the saucer rather than
pouring over the top of the soil. This gives the topsoil a chance to remain
relatively dry as opposed to constantly soaked. The topsoil can be wetted
occasionally, but if it doesn’t also get a chance to dry out you’ll more
likely suffer from bugs, not only that but mould / fungi growing on the
soil.
If you do get an
infestation of something like whitefly the best first option is to try to pick
them all off. Obviously you need to be very careful about using
something like a insecticide. However, it's not completely out of the
question. Some concoctions will state that they are safe for the
treatment of edible plants, given that you do not consume them within a
certain period of time. If you feel you must spray your plants with an insecticide
I would err on the side of caution with regard to harvesting any leaves.
Remember that the manufacturer's instructions may be based on the expectation
that the plants live outside, exposed to the elements, so add at least a
couple of weeks onto the manufacturer's recommended leave period and make sure you
wash the leaf thoroughly after harvesting before consumption.
A battle with
bugs