this article, let me share with all cacti enthusiasts a recipe
of the cacti mix that I have concocted myself, as well as the
different types of pots that I use to pot up the plants in my
cacti collection. I also would like to discuss some issues regarding
repotting, transplanting and watering.
IDEAL CACTI POTTING MIX
me first emphasise that there are many different types of cacti
potting mix available commercially, each with a distinct formula.
One cannot say which brand is better than the other.
the one that works best for you. Give yourself some time to try
out the different mixes. You will be able to know which is the
brand that is most suitable for your plants after some trial and
I find that most commercially prepared cacti mixes are quite expensive
to purchase in large quantities. As it is quite easy to mix up
a mixture from freely available and cheap components, why not
try to prepare a cacti mixture yourself?
most important feature of a cacti mix is that it must be free
draining and it does not remain wet for prolonged periods, as
the roots will very likely rot in such a situation.
FOR A HOMEMADE CACTI POTTING MIX
From top/clockwise - Granite stone, pea gravel, fine gravel,
perlite, soil and the final potting mixture.
chips are used to line the bottom of a pot to allow for easy drainage,
which is absolutely important for cacti. You can also use small-sized
broken down clay or cement bricks instead of granite, so long
as the material allows for easy drainage.
hate waterlogged "wet feet" conditions and their roots will tend
to rot if they remain wet for too long.
brown, hard pebbles are called "pea gravel" in Australia. These
are more commonly known as "LECA" in Singapore. LECA are high
temperature hardened clay particles, which are inert and sold
in many different sizes. In Singapore, nurseries that specialise
in hydroculture will have LECA for sale.
use LECA pellets mainly to cover the surface of the pot, to make
it look nice and neat. It also serves to hold down the particles
of perlite that tend to float to the surface of the mix after
gravel may also be used as part of the potting mixture. Up to
5% LECA can be used in the final potting mixture so that its drainage
is further improved. LECA will come in useful when the soil portion
of the cacti potting mix is clayey.
gravel is used as a substrate to line the bottom of fish tanks.
Easily available in Singapore aquarium shops, fine gravel is used
at a proportion of about 25% of the potting mix.
are small, porous, white particles that are a result of pretreatment
using very high heat. Perlite constitutes 25% of the potting mix.
is not be confused with vermiculite, which is more water retentive
than the former. Vermiculite is not a good additive for potting
most suitable soil type for use in a cacti potting mix is one
that does not contain peat.
soil is preferred over clay-based soil. If you buy clay-based
soils, it is necessary to add more of the other components described
earlier to make it more free draining.
makes up a 50% portion of the total mix.
potting mixture is made up of 50% of soil, 25% of fine gravel
and 25% perlite. Pea gravel can be added to further improve water
drainage, as described earlier.
By mixing the components in this manner, you create a mixture
that will allow for easy drainage and for good aeration for the
resultant cacti potting mix contains relatively low level of nutrients.
It is therefore necessary to fertilise the plants with a liquid
fertiliser during the growth period but not immediately after
transplanting or repotting the cactus or succulent plant.
a fertiliser that has a low level of nitrogen, perferably below
5%. Granular, slow-release fertilisers are not recommended as
they will remain in the soil for too long and may harm the roots,
leading to rot.
& SIZES OF POTS FOR CACTI
Plastic pots on the left and terracotta pots on the right.
are 2 types of pots that are suitable for potting up cacti, namely,
terracotta and plastic. There are pros and cons for using each
type of pot. Terracotta pots are heavier, dry out faster and needs
more frequent watering. Plastic pots, on the other hand, are lighter,
making them easy to handle and keeps the soil moist for a longer
period of time.
use both types currently. I started out with terracotta pots at
first, but now, I prefer to use plastic pots. Surprising trivial,
everyone in Perth over here use black plastic pots, which, by
the way, can be made to look shiny and new looking by applying
some baby oil! This makes your pots more appealling when your
plants are brought to society meetings and competitions.
pot sizes I use nowadays are those that have a diameter of 100
mm. Most cacti can be transplanted into pots of this size and
be left alone for 2 to 3 years. This is what you want, as you
do not disturb the root system by frequent transplanting/repotting.
If the plant is small, then use 50 or 70 mm diameter sized pots.
Above: The importance of having adequate drainage holes
at the bottom of pots.
I have drilled extra holes in my terracotta pots for maximum drainage.
always remove the plant that I have purchased from its original
pot as the mix they use often contains too much peat, which tends
to retain water. It also allows me to check whether the roots
of the plant are diseased or may contain mealybugs. In some cases,
the roots have already overgrown the size of the pot and are protruding
from the underside of the pot and need to be repotted.
remove the plant, I first (especially in the case of plastic pots)
squeeze the pot to dislodge the mixture from clinging to the side
of the pot. Then I shake off as much of the old mix as I can,
taking care not to damage the main tap root, before immersing
the balance in a pot of water to allow remaining portion of the
original mix to be washed off.
that, you can snip off the diseased roots as well as portions
of the root that may be damaged as a result. In the event that
you find mealy bugs, you can wash these bugs off or spray them
with "Confidor", an insecticide that contains Imidacloprid as
the main constituent. Alternatively, you can simply use a cotton
wool stick dipped in methylated spirit to remove these bugs from
After allowing the plant to dry off on a piece of absorbent paper
for a few minutes, I then repot the plant in my mixture.
repotting or transplanting, never water straight away! Leave the
plant alone for about 7 to 10 days to allow the damaged roots
to heal first before you water. It is important for the roots
to heal to avoid fungal or bacterial and rotting problems. Do
not worry - the plant will not die because you did not water!
a general rule, allow only about 1/2 inch space between the plant
and the rim of the pot. The reason is that you do not want to
have too much soil and to maintain the balance between root system
and soil ratio. This is especially important and significant if
you water too much or too often.
pea gravel I use on the top of the soil, like I mentioned earlier,
is only for estatic purposes. It is not entirely necessary, some
people say that because you have the pea gravel on top, you cannot
really tell when the soil is dry and that the plant needs re-watering.
repotted or transplanted plant should be kept in the shade for
a few days before placing the pot in its final location.
A HEALTHY CACTUS PLANTS SHOULD LOOK LIKE
Echinopsis plant shown above is showing healthy growth
since having been transplanted some 10 months ago. I have decided
to dismantle and remove the contents of this pot to show root
how easily the whole contents can be removed from the pot. This
picture shows how a combination of draining material, aerated
mixture and top dressing makes for a suitable root growth environment.
close-up look of the roots and how easily the mixture will fall
away from the plant when immersed in water since the mixture is
a combination of perlite, soil and small, hard particles.
photo shows the plant after mixture has washed off in a pot of
water. Root and root hairs are mostly intact and undamaged. The
root ball is extensive - in just 10 months - healthy roots make
for healthy plants!
the pot sizes I recommended earlier, you can water them once a
week or every 10 days or so, during the season that has fair weather
and more often for the smaller-sized pots.
Singapore when it rains often, be careful not to leave it wet
for too long or too often, especially the hairer cactus species
as they can easily develop fungal problems. As such, try not to
water overhead Water the plant on the soil surface along the edge
of the pot and not on top of the plant itself.
but not least, never allow the pots to sit in trays of water!
Lim first started being interested in Cactus and Succulents some
15 years ago. After his retirement to Perth in 1997 he has actively
pursued his hobby mainly in cacti plants and currently has about
100 different varieties of cacti and succulents in his backyard.