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Seed Starting
Growing Begonias from
Seed
by Brad Thompson
Growing begonias
from seed can seem like something
that only commercial growers and experts can
do. Let me assure you that it’s possible
for anyone to grow seed. The chapter below
will show you the methods that I have used
for years with very good results. They
aren’t the only methods but have been
successful for me. They will be for you
also, if you haven’t already developed good
methods of your own. If you’re successful
already; then continue with what you’re
doing; don’t mess with a good thing If you
are having problems, this chapter just may
help you though.
It really isn’t
complicated, but does require reasonably
sterile conditions, some dexterity and a lot
of patience. In return, you get to watch
little miracles happen. If you follow the
steps I outline below, you should have no
trouble growing seed into mature plants.
I’ll also try to outline problems that you
may run into and my solutions. I start
planting seed in September or October when
the weather is cool and stop planting in
January so that all of the seedlings will
hopefully be large enough to go outside in
April or May. However, seed can be started
any time of the year.
What You Need
Seed
First of all, you need some good seed
but that really goes without saying. At the
end of this chapter you will find directions
for setting your own seed. There are many
sources for seed, many commercial companies
have at least a few varieties of begonia
seed. If you’re an American Begonia Society
member, the best source for buying seed is
through their seed fund. Seed is sometimes
the easiest way to acquire new species of
begonias.
Light
The most
important thing you must have to be
successful with seed is to have a
fluorescent light setup to grow them under.
You could conceivably start the seed on a
windowsill. You usually won’t be successful
growing seed without a light setup unless,
of course, you have your own greenhouse.
Seedlings require
a great deal of even bright light in order
to form compact robust seedlings and you
won’t get that on a windowsill. You’ll get
leggy one-sided seedlings that won’t
transplant well and will probably not be
strong enough to make it to maturity. Under
artificial light they receive constant light
from straight overhead so you won’t end up
with those scraggly leaners like you would
in a window. As far as the artificial light
goes, you don’t need some fancy elaborate
light stand. You can make your own with
just a simple cheap shop light, hung
wherever you have the room. You don’t need
expensive bulbs either. I use whatever is
on sale, usually cool white bulbs, which
will work fine. Those grow-lights may be
better but not enough better to justify the
expense, especially when you have to replace
them every six or eight months.
Potting Mix
For a mix to
start seed in I use one part peat moss (or
Sunshine #3), with a third #2 (small)
perlite. You don’t have to be real
particular because you could probably go
with equal parts of each if you wanted with
no trouble. Sunshine #3 is a commercial
peat based mix that also contains polymers
as a wetting agent. It isn’t much different
than peat moss except that it absorbs and
holds water more easily. There are many
similar peat based mixes that are popular in
different areas of the country. Some
growers lightly cover the top of the mix
with finely ground vermiculite. I have also
successfully grown seed in Miracle Gro™
potting mix. It is more course however and
it already contains fertilizer so don’t add
fertilizer when planting the seed.
Fertilizer
When planting the
seed, I use one quarter strength fertilizer.
I use Miracle-Gro ™ but you can use any
fertilizer with roughly equal numbers. I
also put in a few drops of Superthrive ™
(vitamin B-l) just for a little extra help.
I don’t know for sure if it makes any
difference to the plants but I feel better.
I’ve used it for so long that I really can’t
remember what a difference it made when I
first started using it, but it must have
been good. The main reason I use Miracle-Gro
™ is because it also contains trace elements
but nowadays most fertilizers do.
Containers
I plant my seed
either in 1 1/2 inch pots or take condiment
cups and put holes in the bottom to make my
own pots. Either works just as well as the
other. Some people use shallow trays but
they take up too much space under lights if
you’re planting very many varieties at one
time. After they’re planted, I put the pots
in a small clear plastic shoebox with a
clear lid on top. Any small, clear container
with a clear lid will work as long as it
doesn’t have air holes in it. The purpose
of starting the seed in enclosed containers
is too keep the humidity up, keep the
conditions sterile, and to keep the potting
mix from drying out.
What to Do
Sterilize
You
need to sterilize the container that you’re
going to put the pots of seed into (the
shoebox). I sterilize my containers with a
hot water and bleach solution. There are
many anti-bacterial products you can use for
this but bleach is effective and cheap. I
allow the container to soak for a half-hour
or so to make sure it’s done its work. Wear
gloves when working with a bleach solution.
A ten percent bleach solution should be
strong enough. You should also sterilize
all the pots you’re going to be using to
start the seed in at the same time. Allow
them to dry before using. Condiment cups
should already be sterile.
Preparing the
Pots
Fill
your pots with the prepared potting mix and
pack it down gently in your little pots
almost to the rim. Allow a quarter of an
inch or so for watering. Prepare the
fertilizer water using hot distilled or
boiled water and use it to soak all of your
little pots of soil. I set the pots in a
tray and fill the tray with the water about
an inch deep. I let them sit in the water
for awhile. This has two benefits. One is
the hot water will soak into the peat moss
better so will thoroughly wet it and will
also sterilize your soil mix somewhat at the
same time. Most commercially bagged mixes
should be relatively sterile already if kept
sealed between usage. Make sure you use
pots that won’t melt in boiling water. I
leave them soaking in the water until after
all of the pots are planted, taking each one
out, planting it then putting it back to
make sure the seed on the surface gets wet
also. Make sure the mix has cooled somewhat
before using for planting.
Planting the Seed
To plant the
seed, first make a label with the name of
what you are planting and the date. Put the
label in the pot before you plant it. Since
begonia seed is so fine, it’s hard to keep
track of which ones are planted if you don’t
put the labels in first. Pre-labeling will
save you lots of trouble in the long run.
Plant the seed
by emptying the package onto a clean sheet
of typing paper. Using the paper, allow the
seed to roll off onto the surface of the
mix. Make sure you do your planting away
from the other pots you’re planting. The
seed is so small you could end up with some
of it in nearby pots if you aren’t careful.
Let maybe 50 or a hundred seeds roll off.
If you don’t have good vision, you’ll just
have to wing it. Hopefully, you’ll see that
something is rolling off and be able to
guess when you’ve planted enough. If you
plant less seed, they may not come up well.
Begonia seeds
seem to prefer company and germinate and
grow best will many in the pot. From my
experience if you only have a few seeds in
the pot they don’t thrive as well. If you
plant too many seeds, you’ll have trouble
separating them. Don’t cover the seed,
begonia seed needs light to germinate. Use a
spray bottle to lightly mist the surface of
the pots after planting to make sure the
seed makes good contact with the medium. I
usually use the same fertilizer water in the
spray bottle that I initially used to wet
the mix.
After you have
planted all of your little pots. Again,
seedlings seem to like company so try to
have a container that is shallow and plant
enough little pots to reasonably fill it.
That’s why a plastic shoe box works so well,
it’s shallow and only fits 10 to 15 little
pots at a time, which is a reasonable number
to work with for each planting. After all of
the little pots are filled and labeled, I
take them out of the tray of water and put
them on newspaper for a couple of minutes to
drain. I then place them into the shoe box
and under the lights. I usually line the
shoebox with several thicknesses of
newspaper or paper towel. This will help
collect any moisture that forms on the sides
of the box and distribute it evenly.
Otherwise the water may collect in one end
of the box so a couple pots will be sitting
in water.
I keep the
lights 6 inches or less from the top of the
box and try to run them for at least 14
hours a day. I have left them on 24 hours a
day with good results however. You may be
more energy conscious. The seedlings vary
in sprouting time depending on the variety
and the age of the seed. They can come up
in as quickly as 4 days or not for a month.
I have heard it reported that some varieties
take months to germinate. I guess I will
never grow any of those because if nothing
comes up in a month or so, I remove the pot
and count it as a loss. How long you decide
to give them is up to personal choice. If
you have the room, you can give them longer.
Potential Problems
Drying Out
f
the surface of your mix dries out you can
rewet the mix by misting with a spray
bottle. You can also put the pots in water
in water to soak, leaving them until the
surface of the mix is damp again. No, do
not use boiling water this time. Normally
the pots will stay damp without any
additional rewetting or spraying but this
does happen occasionally. Sometimes too
much bottom heat will make them dry out
faster than they would ordinarily. The
humidity provided by the box is usually
enough to keep them damp till the seedlings
are ready for transplanting.
Algae
If
you see a slimy black or greenish substance
on the surface of the soil, you have an
algae problem. Either the seed had
spores in it or you didn’t sterilize well
enough. You can save any seedlings that look
like they are in danger of being smothered
by transplanting them right away. It is a
delicate procedure when they are that small
especially if you lack dexterity. They
really don’t have any problem with the
transfer as long as you got them out with
some roots attached. Sometimes, moss spores
grow and these will smother out the
seedlings if you don’t transplant them right
away because it grows faster than the
seedlings. There are products that can be
used to kill algae such as Physan™ but I
don’t have experience with using those
products.
Damping off
This disease
shows as seedlings that die off or seedlings
that seem to start growing but then rot and
fall over. It can be caused by several
reasons but the main three are that your mix
is too wet, you didn’t sterilize properly,
or you don’t have enough warmth. Make sure
the pots you plant the seed in has drainage
holes. This will keep the mix from staying
overly wet. Seedlings need warmth to grow
so can damp off if not kept warm enough.
Just as will mature begonias, seedlings
don’t like dampness combined with cold.
Another possible cause is that you don’t
have enough light. Seedlings that are
stretching and reaching for the light are
weaker and more prone to damping off type
problems. There are fungicides you can use
if you already have damping off. You may
have to test whatever product you use first
to see that it works and doesn’t damage
begonia seedlings. I haven’t found that to
be a problem. I have used most products
that worked on mature begonias on seedlings
also with no damage. It’s always best to
test first however.
Tall and Leggy
Seedlings
If
your seedlings appear to be tall and leggy,
you don’t have your lights close enough to
the containers or are not leaving them on
for enough hours. As stated before
seedlings don’t grow well on windowsills.
You should be growing them under artificial
light unless you have a greenhouse.
Transplanting
When to
Transplant
Although seedlings can be transplanted
just as soon as they come up, it is best to
wait for them to get larger before
transplanting unless you are experienced.
When the seedlings first emerge, they have
only a pair of equal sized leaves. These
are the seedling leaves and nourish the
plantlet until it has formed enough roots to
support itself. The seedlings at this point
have only one little root trying to work its
way into the soil.
Within a week or
so after the plantlet comes up, it starts to
form its first true leaf. (If you have ever
looked at a begonia plant , you will notice
that it puts outs one alternating leaf at a
time unlike some other plants which put them
out in pairs.) When this first leaf is out
and is about a half an inch around it’s the
proper size for transplanting. The reason
for this is that it has now reached the
stage where it has formed some roots but not
so many roots that you won’t be able to
separate the little plantlets.
I separate the
little plantlets by grabbing the one true
leaf and gently using it to pull the
plantlet out of the mix. Of course, you
will ruin some but you will have plenty
regardless. If your mix is too hard and the
seedlings don’t come out easily you can use
a knife tip to break up the soil a little
first. As long as your seedling has a root
or two after you pull it out it will be
fine. I usually only transplant about 25 or
so out of the pot at a time and save the
remaining ones in case anything goes wrong
with the first batch. The ones left in the
pot will not grow much because they quickly
run out of food. However, in the humidity
of the sweater box they will sit there in
suspended animation for a long time -
sometimes up to a year. If they dry out
soak the pots to rewet, don’t overhead
water.
What to pot them
in
Transplant the
seedlings into the same conditions you are
removing them from. Use the same soil-less
mix such as peat and perlite, or Sunshine #3
and perlite. Keep them in a sweater box or
clear covered container, at least until the
next transplanting. You can either put the
mix in shallow trays and transplant the
seedlings in little rows or you can use
regular seedling trays cut to fit your
container which have separate little
compartments for each seedling. The ones I
use have individual 1/2 inch squares for
each seedling and seem to work very well. I
have used sandwich boxes cut in half and put
four or five holes in the bottom for
drainage. These worked well too and are
certainly easier to clean than the
commercial seedling trays I use.
I put a shallow
layer of my mix in each tray and sterilize
it by watering with the boiling hot water
with fertilizer (light fertilizer, 1/4
strength) and let the trays of mix soak for
a while to absorb the proper amount of water
and to cool off. After they have cooled a
little, I set them on newspaper to drain,
usually tipped slightly on edge so they
drain easier. I then take a pencil or pen
and use the point to make little holes 1/4
inch deep or so, at regular spacing, about
1/2 inch apart for the seedlings to go
into. I also sterilize a sweater box for
them to go into after they’re planted, with
a bleach and hot water solution After the
sweater box is dry I put several layers of
newspaper in the bottom. This will absorb
any extra moisture from condensation when
you have the trays in it so they won’t be
sitting in water.
Transplanting
Once you have
everything prepared, get your pot of
seedlings and immediately copy the label and
put it in the tray you’re going to
transplant into so you won’t forget to do it
later. No, you won’t remember what they
were no matter how well intentioned you are,
as I can swear to. (As can Mary Sakamoto
when she’s looked in one of my sweater boxes
and said, “Oh what are these? There isn’t a
label”, and I suddenly remember that I don’t
remember.) Avoid the confusion and
label first.
Pull up a
seedling, as described above, and set it
into the hole you made with the pencil. If
it doesn’t fit then make your holes a little
bigger. Repeat this process until you’ve
transplanted as many as you want. Then go
back with your pencil, or whatever your
favorite utensil is, and smooth around any
that need it. They don’t need much tamping
around; if you made contact with the soil
they will root and grow. After planting, I
give them a misting with the spray bottle as
with the seed. If you soaked the mix
properly in the first place, they shouldn’t
need any further watering until they are
ready for the next transplanting.
If any start to
die or rot, you have the mix too wet or not
sterile enough, so open the lid a crack to
let it dry out some. If that doesn’t work
and they are still dying off, as a last
resort spray them with a fungicide to try
and kill the fungus problem the too wet
conditions created. Don’t be discouraged if
you have some failures. Count those as
learning experiences and try again.
Where to go from there
About a month or
month and a half from that first
transplanting they should have grown to fill
the surface of the tray. It’s time to move
them up again. At this stage they are
running out of food and are becoming too
crowded. They’ll either just sit there and
not grow any more or they’ll get leggy and
be hard to make into nice plants or to
transplant.
They should be
ready to transplant into small 1 to 1 1/2
inch size pots at this time. You don’t have
to be quite as concerned at this stage about
perfectly sterile conditions as in the
earlier stages but your sweater box should
be sterilized. Fill your little pots with
mix as when you planted the seed. You can
use a knife tip to make an opening in the
mix to receive the little plant. I use my
mix dry, transplant the little plant and put
the pots in a shallow tray filled with the
cold or room temperature fertilizer water to
soak. Make sure to label each pot as you go
so you won’t miss any, or if only one type
of seedlings are going in one sweater box
you can just put in one label for the box
and label them before you take them out.
I usually move
the plantlets out of the sweater box when
they have grown to fill this size pot or
after they have reached the next size pot.I
put them under lights on stands that are
totally covered in plastic to keep the
humidity in. I place the small pots on a
shallow tray filled with a layer of perlite
to soak up any water from watering the
plants and also to raise the humidity.
Watering the perlite occasionally to keep it
moist is necessary because the runoff from
watering the little pots is not enough.
After they have grown to fill these pots,
you can treat them like regular plants. Lift
the plastic cover gradually to harden them
off and then transplant in your regular mix.
If it is warm enough, you can move them
outside in full shade for another couple of
weeks and then start moving them into your
regular growing areas.
Making and Collecting your own Begonia
Seed
There are two
types of begonia seed, hybrid seed and
species seed. Hybrid seed is seed that is
created by pollinating one variety of
begonia with the pollen from another variety
of begonia. Species seed comes from self
pollinating wild species of begonias. Only
species will come true from seed.
There are also
three types of pollination, self
pollination, cross pollination, and open
pollination. Self pollination involves
pollinating a begonia with its own pollen or
the pollen from another begonia of the same
species or variety. Cross pollination
involves using the pollen from an different
variety to pollinate. The seedlings that
result from cross pollination are call
hybrids. Open pollination is when a begonia
is pollinated without human help either by
insects or the wind.
If your desire is
to produce seed of species, either for
yourself or to share that species with
others, you must self pollinate the
species. If you only have one plant of the
species, it’s acceptable to use the pollen
of that plant to pollinate it’s own female
flowers. However, for genetic diversity,
it’s better to gather pollen from another
plant of the same species for the
pollination. Many species of begonias are
rare or endangered both in the wild and in
cultivation. If you own species of
begonias, you should make every attempt to
self pollinate all of them to help keep them
in cultivation. This seed can be shared
with friends, with seed funds, or as back up
in case you lose a parent plant.
If your desire is
to produce hybrid begonia seed, all of the
methods are acceptable. Hand pollinating
yourself is preferred however. Any seed
removed from a hybrid plant is hybrid seed,
whether self, cross, or open pollinated.
Most hybrids can only be reproduced using
cuttings except for a few strains of
semperflorens and tuberous hybrids. You
can’t self pollinate a hybrid such as
B.’ Irene Nuss’, collect the seed and grow
more B. ‘Irene Nuss' begonias from it. Any seed
produced by a hybrid will result in new
hybrids and not recreations of the parent.
Unlike many other
types of plants, begonias have separate male
and female flowers. On most varieties, the
males come out first in the flower cluster.
As they fall off, the female flowers come
out. There are a handful of exceptions.
Finding the
Pollen
With begonias,
especially hybrids, which parents you choose
to pollinate with depends also on which ones
you can find pollen on. Some hybrids either
don’t produce pollen because they’re sterile
or the flowers fall off without opening. On
others the pollen just doesn’t mature before
the flower falls off. It won’t take you too
long to learn which ones never have pollen.
There are also hybrids that were crosses
between two very unrelated types of begonias
that don’t have complete flowers. Those
won’t have pollen either, like B. ‘Question
Mark’ that doesn’t have any anthers. Any
true specie however has to have pollen,
that’s the only way it can reproduce itself
in the wild. If a species begonia doesn’t
have pollen it’s a cultural problem. A
change in something you’re doing like
overwatering, humidity, etc., may get it to
produce pollen, if it wasn’t.
On begonias, the
male flowers are the flowers that have no
ovaries behind the petals. They usually
have four or petals and a cluster of anthers
in the middle. The easiest way to test for
pollen is to take a mature male flower
that’s fully open. Hold it up to bright
light and gently flick your fingernail
across the anthers (the anthers are the
yellow parts in the center of the flower).
If there is pollen you should see a little
puff of yellow dust flick out. If you have
trouble seeing, try flicking the stamens
across a piece of black paper and you should
see the pollen on it. The best time to check
is early afternoon when the pollen is more
likely to be ready because it’s warm and
dry.
Choosing the
Female Flower
Female flowers
are usually ready to pollinate when they
have been open for a couple days and the
petals are open to their fullest. Some
varieties open fully with the petals curled
slightly back but not all open fully. I
usually choose a cluster that has several
female flowers that are ready. On begonias,
the female flowers have a winged ovary
behind the petals.
I usually take
three or more male flowers that I know have
pollen off of the father plant for the
pollinating. On the mother plant I take the
cluster that I’m going to pollinate and
remove any male flowers (so it can’t self
pollinate) even from other close clusters.
On species it is wise to keep all male
flowers removed in advance of crossing it
because the wind can cause it to self
pollinate. I also remove any immature
female flowers from the cluster. They take
away energy from the ones you’re pollinating
and you won’t have to remember that there
were some in that cluster you didn’t
pollinate.
To do the
pollinating, take the male flower and gently
bend the petals back, as a handle, to fully
expose the anthers and gently brush it in
the center of the female flower. As I said,
I use three or more males and with these I
brush across all the female flowers in the
cluster just to make sure all get
pollinated. To mark the cross (this is
extremely important) I use a narrow
strip of mailing or computer label with the
cross written on it and bend it across the
flower stem. Use a pencil to write on the
label so it doesn’t wash off.
If your
pollination was successful, in the next day
or so, the petals on the females will close
and eventually drop off. If they don’t
close by the second day, then reapply pollen
to make sure the pollination is successful.
The petals don’t always close on all
varieties, so it may still have taken even
if they don’t close. A sure sign is the
ovaries start to grow fatter. This shows
something is happening in there.
Harvesting the
Seed
It will take a
month or so for the pods to ripen so be
patient. Some varieties may take a lot
longer but a month is normally the time
period for the majority of begonias. When
the flower stems dry up or shrivel, you can
remove the pods whether they are dry or
not. They won’t get any more sustenance
when the stems have shriveled so you can’t
hurt anything by taking them off. Don’t
take them off before this time. They won’t
have matured to their full potential. If
you’re in doubt leave the pods on till
they’re fully dry. Make sure you watch them
and take them as soon as you see the pods
start to split or you may lose all of your
seed though.
After collecting
them place the mature pods into small
plastic film canisters, medicine bottle, or
something similar to finish drying.Don’t put
a cover on because you need to make sure
they get fully dry and don’t rot. Leave
them for at least a week or more to be
sure. If you have pods that fell off just
when you thought they were almost ready you
can try drying them. They usually don’t have
good seed, but you may get lucky. Make sure
you label the container with the cross to
keep track of what that seed is.
Cleaning and
Packaging the Seed
Open the pods on
a sheet of typing paper. To separate the
good seed from the chaff, tilt the paper
slightly to roll the good seed off onto
another piece of paper. The chaff and
immature seed is left behind. If nothing
rolls then it probably is all chaff and not
good seed. There are some begonia seeds
that are oddly shaped or so small they don’t
roll easily so rolling isn’t a hundred
percent method. To be absolutely sure about
seed that doesn’t roll you can examine it
under a cheap microscope. Most good seed
looks like popcorn kernels under
magnification. For comparison, you can look
at seed that you know is good so you can see
what it should look like. Bad seed looks
shriveled, cracked or distorted under the
microscope. If still in doubt, seek out an
expert if there is one in your area.
Fold the cleaned
seed into a small piece of paper and tape it
closed. You can also use small envelopes
such as made for stamps. Most regular
envelopes however aren’t air tight enough to
contain the begonia seed since it’s so
small. Write the seed information on the
outside with the date. Since I don’t plant
seed until late fall, I just keep them in a
coffee can or box until planting time. In
the winter when I’m done with all the
planting I’m going to do that season I store
the remaining seed in the refrigerator. You
need to use a moisture resistant container
to store the seed, such as a Tupperware
container, when storing long term in the
fridge. Begonia seed will last for many
years in the refrigerator. I know I’ve had
seed that was viable ten years later.
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