Telos Rare Bulbs
Tue, 05 Dec 2006 08:50:35 PST
Dear All:

We had a discussion not long ago about germinating Tropaeolum seed.  It has
a reputation for being difficult, and I, myself have had difficulties in the
past.  I have a very nice collection of about ten species, most of which I
grew from seed from Watson & Flores.  Their seed germinated just fine - why
didn't mine?  I figured that the difference could be that my seed was stored
in cool conditions.  I don't refrigerate it, but it had been kept in a room
that never goes above 60F.  This year I left the seed it its containers in
the greenhouse where temperatures routinely went above 100F on sunny days,
and usually reached about 80F on foggy/cloudy days.  It was stored in open
containers out of direct sun.  Then, about six weeks ago I soaked the seed
for 48 hours with a tiny dab of dish detergent to break the surface tension.
After 48 hours I could dent the seed coat with a fingernail, so I decided
that was enough for water to penetrate the seed coat.  I then sowed the seed
in damp vermiculite in plastic zip-lock bags in the refrigerator.  I am very
happy to say that so far I have got about 50% germination on all species.  I
expect more to germinate.  This is so far better than any of my experience
in the past.  I have tried soaking, soaking in giberellic acid and sowing in
the refrigerator before, with modest success, but nothing like this.

From this I would conclude that the seed needs a conditioning period at warm
temperatures after it has ripened.  There are other seeds out there that
need this also, and it doesn't have to be when the seed is sown, but can be
during dry storage.  We often store seed in the refrigerator, and for many,
this is the best thing, but for Tropaeolum obviously it isn't.

Unfortunately, by the time my Tropaeolum azureum tubers bloomed, I was so
busy with other things I didn't hand-pollinate, so I didn't get seed from
that species, but I certainly will next year!!

Telos Rare Bulbs

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