Dry
Seed Preparation vs. "Greencapping"
Our preference is for the capsules to mature on the
plant, keep a close eye on them and when they just start to
split, harvest the caps rather than to remove green capsules
early. "Greencapping" is a common practice, with the primary
reason for doing it being that the unopened caps will have
uncontaminated seed inside, but unfortunately that isn't
always true. Just because the cap is closed does NOT mean
that the contents haven't been exposed to bacteria or fungus
that has penetrated the plant tissue. So, the best practice
in the lab is to disinfect even green seed, but if the seed
is too young it will be harmed by the disinfecting process.
Also, green seed is reported to pass on virus to the
offspring, while mature, dry seed does not. Virus may not be
killed by disinfection. Also, unless prepared properly and
shipped and used immediately a greencap can spoil. Additionally,
a greencap must all be sown at once, leaving no opportunity to
hold back and seed in case a second attempt is needed.
There are some species that need to be greencapped because
mature seed is difficult to germinate. In these cases
greencapping may be essential for success, and, in our
opinion, greencapping is best only used in these cases.
Seed
Harvest and Drying
When a capsule is nearing maturity you need to keep a
close eye out for splitting. Caps usually (but not always)
split near the column end first. If you can't check daily
then you should tie a coffee filter or some such thing over
the near-ripe capsule to help catch seed and to help keep
airborne contaminants out. You might consider moving a plant
with near-ripe capsules out of the greenhouse to a less
humid, less pathogen-rich environment, perhaps your
house.
![Split Capsule](http://troymeyers.com/images/justsplit.jpg)
A Capsule that has just
split - note the gaps on the column
end
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When a capsule splits, sometimes it takes days but
sometimes only hours for it to open completely. If you
remove a split capsule from the plant and lay it on a coffee
filter and then cut the column off with a sterile razor
blade, the cap will likely spring open a bit and seed will
drop out immediately.
![Cut Capsule](http://troymeyers.com/images/justcut.jpg)
Same capsule after
cutting off column end with a sterile blade - note
how it has sprung open and seed has immediately
fallen out
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Size permitting, you can staple the stem to the upper
edge of the coffee filter. Huge capsules will need to be
suspended with appropriate ingenuity on your part.
![Stapled to Filter Paper](http://troymeyers.com/images/caphang.jpg)
Capsule is stapled to
edge of coffee filter to dangle while drying and
opening further
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Protect it from blowing air by slipping it into a jar or
other container, but DON'T put a lid on the jar as the seed
may mold from the humidity from the moisture in the meaty
capsule walls.
![Paper in Jar](http://troymeyers.com/images/injar.jpg)
The filter is tucked into the jar to
allow free drying and protect from breezes that
would carry away the seed.
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Once the capsule is fairly dry (a few days) the good seed
will fall out by tapping it lightly. Scraping usually isn't
needed, and if done unnecessarily it just adds useless
material that complicates the disinfection process.
![Dry Capsule](http://troymeyers.com/images/cap2day.jpg)
After two days, in this
case, the carpels have dried, and seed has fallen
out. Only tapping was needed to get the best of the
seed.
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Remove the capsule remains, fold up the coffee filter so
that seed can't spill, and secure it shut with a little tape
or a couple of staples so that we will be able to open it
without spilling seed and label it. Good things to put on
the label are genus & species of parent(s), whether it
is a selfing, outcross, or other, pollination date, harvest
date, number of capsules contained, and any identifying
number assigned by you or us.
If there is a lot of seed from a huge capsule, further
drying may be appropriate, and if so, once the meaty carpels
have been removed, the packet can be place in a closed jar
with a very active desiccant such as calcium chloride. A passive
desiccant such as silica gel does not have a sufficient uptake rate
and will cause problems, unless the seed is dry already.
This finishing drying should be done at room
temperature still, since drying is retarded if it is placed in
a refrigerator.
It is usually best to only put the contents of one
capsule in each paper packet even though they are from the
same plant and pollen parent. This is because we examine the
seed under a microscope and often we find that one cap may
have seeds with no embryos or with mold mycelia while
another may be good seed... and to mix them together would
be a shame.
After the dry seed is out of the cap, it should be sent
to us immediately, or if you are keeping it, when fully dry
only it should be stored in the refrigerator in a jar with
a humidity-controlling mixture. A good one is equal parts
by volume of calcium chloride pellets and water, such as
a tablespoon of each, in a small open container inside the
jar.
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