These notes are intended as
a guide for those who are already aware of the basic cultivation for
tuberous begonias, which are covered elsewhere on the website.
The main points to bear in mind for the successful cultivation of plants
intended for exhibition as cut blooms are: -
1. Obtain the
right varieties not all varieties are suitable for cut bloom
work, some are better as pot plants whilst a few are ideal for both.
The best way to find the varieties you need is by looking to see the
ones that win the prizes at the shows or asking other growers.
2. Grow only one main stem with no side shoots and allow only
one bloom to flower on each plant.
3. Provide the right growing conditions shade at all
times, high humidity up until bud selection (discussed later) and
cool airy conditions.
4. Avoid the 3 overs Over-watering, Over-feeding and
5. Time the potting of plants and buds to the intended show.
6. Always do the right thing at the right time. If it needs
doing today, tomorrow may be too late.
In view of the increased
incidence of tarsonamid mite it is worth treating the tubers by
immersing them in a 10% solution of Domestos and water for 15 minutes,
followed by a rinse for 15 minutes in clean water. Domestos is
important, ordinary bleach will not do!
If the tubers are not
pipped when removed from storage place them upside down on soil warming
cables heated to 75F. for two weeks, this should pip them nicely.
The starting time for
pipped tubers should be about 20 weeks before the show date. The reason
for this is that we need to allow for the following growing procedure: -
tubers in a seed compost or 50/50 mix of multi-purpose and peat.
weeks after starting first potting into a pot that will just take the
root-ball using a multi-purpose compost.
weeks later pot on 2 pot sizes (e.g. 4" to 6") using a good
potting strength compost.
weeks pot into final pots (another 2 pot sizes) using the same
before the show start feeding at Ό strength high potash feed at 3 out
of 4 feeds with plain water at the 4th.
weeks are approximate and you should be guided by the root activity
which should be about 2/3 of the way down the outside of the root-ball
at each new potting on. Take great care not to over-water at any stage. The
best way to avoid this is to use very moist compost and not water for
several days afterwards.
should be started on heated beds at about 65 70F. and once potted
into the first pots kept as cool as possible. A temperature of 45
50F. is quite ok as long as you avoid over-watering.
equally important not to let the compost dry out particularly whilst on
the heated beds as major root damage will occur.
view of the need to grow only one shoot, remove all extra shoots when
about 3" - 4" long and use as cuttings. Also remove all side
shoots as small as possible. If they are rubbed out as they form no
treatment of the wound will be necessary.
plants should be grown on as steadily as possible, re-potting at the
the time to prevent attacks by pest and disease. Spray with fungicide at
two weekly intervals from the first potting until 6 - 7 weeks before the
show date. If possible use a different spray each time, but dont
bother with Nimrod, as this is not effective. Provado appears to be
effective against vine-weevil and a treatment straight after final
potting is recommended.
buds should be removed until 6 weeks before the show when they should be left until
selection time which is 4 weeks before the show date. The bud to look
for at this time is as near to, but not over 2" in size. This size,
with average growing conditions, should be right for the show day.
now on you are at the mercy of the weather at it as well to time some
buds early and some late if you have enough plants.
plant should now be stopped (i.e. the growing point removed) leaving one
leaf above the selected bud. The side buds should also be removed as
soon as they can be handled without touching the main bud.
now starts as mentioned earlier. Up to this point no supplementary feed
whatsoever has been given. Many growers top-dress the pots with compost
at the stage, but I do not believe it is necessary and find it
or so after taking the bud, the forming bloom should be starting to open
and be at what is called the "oyster" stage. It is now time to
place the collar on the back of the bloom. This collar is made either
from polystyrene or cardboard and is a 9" disc with a slot cut to
enable it to be fitted behind the bloom.
collar should be fitted behind the bloom but in front of the leaves.
extending bloom support should be fitted behind the collar to hold it
against the back of the bud. This support will need adjusting as the
bloom stem lengthens.
not now be necessary to touch the bloom again until it is actually
night before the show the blooms will be cut and this should be done by
holding the back of the collar and cutting the stem as long as possible.
Once the bloom is removed from the plant cut 1 inch from the stem before
placing in a bloom tube containing either flower food or lemonade. The
extra cut removes the air lock which forms when the first cut is made
and reduces the risk of collapse on the board.
important thing now is to avoid damage to the blooms and check the show
schedule to ensure compliance. It is a great pity to fall at the last
hurdle after 6 months of work.